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	diff --git a/MatrixElement/Lepton/MEee2gZ2qq.h b/MatrixElement/Lepton/MEee2gZ2qq.h
	--- a/MatrixElement/Lepton/MEee2gZ2qq.h
	+++ b/MatrixElement/Lepton/MEee2gZ2qq.h
	@@ -1,580 +1,580 @@
	// -- C++ --
	//
	// MEee2gZ2qq.h is a part of Herwig++ - A multi-purpose Monte Carlo event generator
	// Copyright (C) 2002-2007 The Herwig Collaboration
	//
	// Herwig++ is licenced under version 2 of the GPL, see COPYING for details.
	// Please respect the MCnet academic guidelines, see GUIDELINES for details.
	//
	#ifndef HERWIG_MEee2gZ2qq_H
	#define HERWIG_MEee2gZ2qq_H
	//
	// This is the declaration of the MEee2gZ2qq class.
	//

	#include "Herwig++/MatrixElement/HwMEBase.h"
	#include "Herwig++/Models/StandardModel/StandardModel.h"
	#include "ThePEG/PDT/EnumParticles.h"
	#include "ThePEG/Repository/EventGenerator.h"
	#include "ThePEG/Utilities/Rebinder.h"
	#include "Herwig++/MatrixElement/ProductionMatrixElement.h"
	#include "ThePEG/Helicity/WaveFunction/SpinorWaveFunction.h"
	#include "ThePEG/Helicity/WaveFunction/SpinorBarWaveFunction.h"

	namespace Herwig {

	using namespace ThePEG;

	/**
	* The MEee2gZ2qq class implements the matrix element
	* for \f$e^+e^-\to Z/\gamma \to q\bar{q}\f$ including spin correlations.
	* The class includes greater control over the type of quark produced than is available
	* in the corresponding matrix element from ThePEG, in addition to spin correlations.
	*
	* @see \ref MEee2gZ2qqInterfaces "The interfaces"
	* defined for MEee2gZ2qq.
	*/
	class MEee2gZ2qq: public HwMEBase {

	public:

	/**
	* The default constructor.
	*/
	MEee2gZ2qq() : minflav_(1), maxflav_(5), massopt_(1), pTmin_(GeV),
	preFactor_(6.)
	{}

	/**
	* Members for hard corrections to the emission of QCD radiation
	*/
	//@{
	/**
	* Has a POWHEG style correction
	*/
	virtual bool hasPOWHEGCorrection() {return true;}

	/**
	* Has an old fashioned ME correction
	*/
	virtual bool hasMECorrection() {return true;}

	/**
	* Initialize the ME correction
	*/
	virtual void initializeMECorrection(ShowerTreePtr, double &,
	double & );

	/**
	* Apply the hard matrix element correction to a given hard process or decay
	*/
	virtual void applyHardMatrixElementCorrection(ShowerTreePtr);

	/**
	* Apply the soft matrix element correction
	* @param initial The particle from the hard process which started the
	* shower
	* @param parent The initial particle in the current branching
	* @param br The branching struct
	* @return If true the emission should be vetoed
	*/
	virtual bool softMatrixElementVeto(ShowerProgenitorPtr initial,
	ShowerParticlePtr parent,
	Branching br);

	/**
	* Apply the POWHEG style correction
	*/
	virtual HardTreePtr generateHardest(ShowerTreePtr);
	//@}

	/** @name Virtual functions required by the MEBase class. */
	//@{
	/**
	* Return the order in \f$\alpha_S\f$ in which this matrix
	* element is given.
	*/
	virtual unsigned int orderInAlphaS() const;

	/**
	* Return the order in \f$\alpha_{EW}\f$ in which this matrix
	* element is given.
	*/
	virtual unsigned int orderInAlphaEW() const;

	/**
	* The matrix element for the kinematical configuration
	* previously provided by the last call to setKinematics(), suitably
	* scaled by sHat() to give a dimension-less number.
	* @return the matrix element scaled with sHat() to give a
	* dimensionless number.
	*/
	virtual double me2() const;

	/**
	* Return the scale associated with the last set phase space point.
	*/
	virtual Energy2 scale() const;

	/**
	* Add all possible diagrams with the add() function.
	*/
	virtual void getDiagrams() const;

	/**
	* Get diagram selector. With the information previously supplied with the
	* setKinematics method, a derived class may optionally
	* override this method to weight the given diagrams with their
	* (although certainly not physical) relative probabilities.
	* @param dv the diagrams to be weighted.
	* @return a Selector relating the given diagrams to their weights.
	*/
	virtual Selector<DiagramIndex> diagrams(const DiagramVector & dv) const;

	/**
	* Return a Selector with possible colour geometries for the selected
	* diagram weighted by their relative probabilities.
	* @param diag the diagram chosen.
	* @return the possible colour geometries weighted by their
	* relative probabilities.
	*/
	virtual Selector<const ColourLines *>
	colourGeometries(tcDiagPtr diag) const;

	/**
	* Construct the vertex of spin correlations.
	*/
	virtual void constructVertex(tSubProPtr);
	//@}


	public:

	/** @name Functions used by the persistent I/O system. */
	//@{
	/**
	* Function used to write out object persistently.
	* @param os the persistent output stream written to.
	*/
	void persistentOutput(PersistentOStream & os) const;

	/**
	* Function used to read in object persistently.
	* @param is the persistent input stream read from.
	* @param version the version number of the object when written.
	*/
	void persistentInput(PersistentIStream & is, int version);
	//@}

	/**
	* The standard Init function used to initialize the interfaces.
	* Called exactly once for each class by the class description system
	* before the main function starts or
	* when this class is dynamically loaded.
	*/
	static void Init();

	protected:

	/** @name Clone Methods. */
	//@{
	/**
	* Make a simple clone of this object.
	* @return a pointer to the new object.
	*/
	virtual IBPtr clone() const {return new_ptr(*this);}

	/** Make a clone of this object, possibly modifying the cloned object
	* to make it sane.
	* @return a pointer to the new object.
	*/
	virtual IBPtr fullclone() const {return new_ptr(*this);}
	//@}

	protected:

	/** @name Standard Interfaced functions. */
	//@{
	/**
	* Initialize this object after the setup phase before saving an
	* EventGenerator to disk.
	* @throws InitException if object could not be initialized properly.
	*/
	virtual void doinit();

	/**
	* Rebind pointer to other Interfaced objects. Called in the setup phase
	* after all objects used in an EventGenerator has been cloned so that
	* the pointers will refer to the cloned objects afterwards.
	* @param trans a TranslationMap relating the original objects to
	* their respective clones.
	* @throws RebindException if no cloned object was found for a given
	* pointer.
	*/
	virtual void rebind(const TranslationMap & trans)
	;

	/**
	* Return a vector of all pointers to Interfaced objects used in this
	* object.
	* @return a vector of pointers.
	*/
	virtual IVector getReferences();
	//@}

	protected:

	/**
	* Calculate the matrix element for \f$e^-e^-\to q \bar q\f$.
	* @param partons The incoming and outgoing particles
	* @param momenta The momenta of the incoming and outgoing particles
	* @param first Whether or not to calculate the spin correlations
	*/
	double loME(const vector<cPDPtr> & partons,
	const vector<Lorentz5Momentum> & momenta,
	bool first) const;

	/**
	* Member to calculate the matrix element
	* @param fin Spinors for incoming fermion
	* @param ain Spinors for incoming antifermion
	* @param fout Spinors for outgoing fermion
	* @param aout Spinors for outgong antifermion
	* @param me Spin summed Matrix element
	* @param cont The continuum piece of the matrix element
	* @param BW The Z piece of the matrix element
	*/
	ProductionMatrixElement HelicityME(vector<SpinorWaveFunction> & fin,
	vector<SpinorBarWaveFunction> & ain,
	vector<SpinorBarWaveFunction> & fout,
	vector<SpinorWaveFunction> & aout,
	double & me,
	double & cont,
	double & BW ) const;

	/**
	* The ratio of the matrix element for one additional jet over the
	* leading order result. In practice
	- * \f[\frac{\hat{s}\|\overline{\mathcal{M}}\|^2_2\|D_{\rm emit}\|}{4\pi C_F\alpha_S\|\overline{\mathcal{M}}\|^2_3\left(\|D_{\rm emit}\|+\|D_{\rm spect}\right)}}\f]
	+ * \f[\frac{\hat{s}\|\overline{\mathcal{M}}\|^2_2\|D_{\rm emit}\|}{4\pi C_F\alpha_S\|\overline{\mathcal{M}}\|^2_3\left(\|D_{\rm emit}\|+\|D_{\rm spect}\|\right)}\f]
	* is returned where \f$\\|\overline{\mathcal{M}}\|^2\f$ is
	* the spin and colour summed/averaged matrix element.
	* @param partons The incoming and outgoing particles
	* @param momenta The momenta of the incoming and outgoing particles
	* @param iemitter Whether the quark or antiquark is regardede as the emitter
	* @param subtract Whether or not to subtract the relevant dipole term
	*/
	double meRatio(vector<cPDPtr> partons,
	vector<Lorentz5Momentum> momenta,
	unsigned int iemitter,
	bool subtract =false) const;

	/**
	* Calculate the matrix element for \f$e^-e^-\to q \bar q g\f$.
	* @param partons The incoming and outgoing particles
	* @param momenta The momenta of the incoming and outgoing particles
	*/
	InvEnergy2 realME(const vector<cPDPtr> & partons,
	const vector<Lorentz5Momentum> & momenta) const;

	private:

	/**
	* Apply the hard matrix element
	*/
	vector<Lorentz5Momentum> applyHard(const ParticleVector &p);

	/**
	* Get the weight for hard emission
	*/
	double getHard(double &, double &);

	/**
	* Set the \f$\rho\f$ parameter
	*/
	void setRho(double);

	/**
	* Set the \f$\tilde{\kappa}\f$ parameters symmetrically
	*/
	void setKtildeSymm();

	/**
	* Set second \f$\tilde{\kappa}\f$, given the first.
	*/
	void setKtilde2();

	/**
	* Translate the variables from \f$x_q,x_{\bar{q}}\f$ to \f$\tilde{\kappa},z\f$
	*/
	//@{
	/**
	* Calculate \f$z\f$.
	*/
	double getZfromX(double, double);

	/**
	* Calculate \f$\tilde{\kappa}\f$.
	*/
	double getKfromX(double, double);
	//@}

	/**
	* Calculate \f$x_{q},x_{\bar{q}}\f$ from \f$\tilde{\kappa},z\f$.
	* @param kt \f$\tilde{\kappa}\f$
	* @param z \f$z\f$
	* @param x \f$x_{q}\f$
	* @param xbar \f$x_{\bar{q}}\f$
	*/
	void getXXbar(double kt, double z, double & x, double & xbar);

	/**
	* Soft weight
	*/
	//@{
	/**
	* Soft quark weight calculated from \f$x_{q},x_{\bar{q}}\f$
	* @param x \f$x_{q}\f$
	* @param xbar \f$x_{\bar{q}}\f$
	*/
	double qWeight(double x, double xbar);

	/**
	* Soft antiquark weight calculated from \f$x_{q},x_{\bar{q}}\f$
	* @param x \f$x_{q}\f$
	* @param xbar \f$x_{\bar{q}}\f$
	*/
	double qbarWeight(double x, double xbar);

	/**
	* Soft quark weight calculated from \f$\tilde{q},z\f$
	* @param qtilde \f$\tilde{q}\f$
	* @param z \f$z\f$
	*/
	double qWeightX(Energy qtilde, double z);

	/**
	* Soft antiquark weight calculated from \f$\tilde{q},z\f$
	* @param qtilde \f$\tilde{q}\f$
	* @param z \f$z\f$
	*/
	double qbarWeightX(Energy qtilde, double z);
	//@}

	/**
	* ????
	*/
	double u(double);

	/**
	* Vector and axial vector parts of the matrix element
	*/
	//@{
	/**
	* Vector part of the matrix element
	*/
	double MEV(double, double);

	/**
	* Axial vector part of the matrix element
	*/
	double MEA(double, double);

	/**
	* The matrix element, given \f$x_1\f$, \f$x_2\f$.
	* @param x1 \f$x_1\f$
	* @param x2 \f$x_2\f$
	*/
	double PS(double x1, double x2);
	//@}

	protected:

	/**
	* Pointer to the fermion-antifermion Z vertex
	*/
	AbstractFFVVertexPtr FFZVertex() const {return FFZVertex_;}

	/**
	* Pointer to the fermion-antifermion photon vertex
	*/
	AbstractFFVVertexPtr FFPVertex() const {return FFPVertex_;}

	/**
	* Pointer to the particle data object for the Z
	*/
	PDPtr Z0() const {return Z0_;}

	/**
	* Pointer to the particle data object for the photon
	*/
	PDPtr gamma() const {return gamma_;}

	/**
	* Pointer to the particle data object for the gluon
	*/
	PDPtr gluon() const {return gluon_;}

	private:

	/**
	* The static object used to initialize the description of this class.
	* Indicates that this is a concrete class with persistent data.
	*/
	static ClassDescription<MEee2gZ2qq> initMEee2gZ2qq;

	/**
	* The assignment operator is private and must never be called.
	* In fact, it should not even be implemented.
	*/
	MEee2gZ2qq & operator=(const MEee2gZ2qq &);

	private:

	/**
	* Pointer to the fermion-antifermion Z vertex
	*/
	AbstractFFVVertexPtr FFZVertex_;

	/**
	* Pointer to the fermion-antifermion photon vertex
	*/
	AbstractFFVVertexPtr FFPVertex_;

	/**
	* Pointer to the fermion-antifermion photon vertex
	*/
	AbstractFFVVertexPtr FFGVertex_;

	/**
	* Pointer to the particle data object for the Z
	*/
	PDPtr Z0_;

	/**
	* Pointer to the particle data object for the photon
	*/
	PDPtr gamma_;

	/**
	* Pointer to the particle data object for the gluon
	*/
	PDPtr gluon_;

	/**
	* The minimum PDG of the quarks to be produced
	*/
	int minflav_;

	/**
	* The maximum PDG of the quarks to be produced
	*/
	int maxflav_;

	/**
	* Option for the treatment of the top quark mass
	*/
	unsigned int massopt_;

	/**
	* CM energy
	*/
	Energy d_Q_;

	/**
	* Quark mass
	*/
	Energy d_m_;

	/**
	* The rho parameter
	*/
	double d_rho_;

	/**
	* The v parameter
	*/
	double d_v_;

	/**
	* The initial kappa-tilde values for radiation from the quark
	*/
	double d_kt1_;

	/**
	* The initial kappa-tilde values for radiation from the antiquark
	*/
	double d_kt2_;

	/**
	* Cut-off parameter
	*/
	static const double EPS_;

	/**
	* Pointer to the coupling
	*/
	ShowerAlphaPtr alpha_;

	private:

	/**
	* Variables for the POWHEG style corrections
	*/
	//@{
	/**
	* The cut off on pt, assuming massless quarks.
	*/
	Energy pTmin_;

	/**
	* Overestimate for the prefactor
	*/
	double preFactor_;

	/**
	* ParticleData objects for the partons
	*/
	vector<cPDPtr> partons_;

	/**
	* Momenta of the leading-order partons
	*/
	vector<Lorentz5Momentum> loMomenta_;
	//@}

	};

	}

	#include "ThePEG/Utilities/ClassTraits.h"

	namespace ThePEG {

	/** @cond TRAITSPECIALIZATIONS */

	/** This template specialization informs ThePEG about the
	* base classes of MEee2gZ2qq. */
	template <>
	struct BaseClassTrait<Herwig::MEee2gZ2qq,1> {
	/** Typedef of the first base class of MEee2gZ2qq. */
	typedef Herwig::HwMEBase NthBase;
	};

	/** This template specialization informs ThePEG about the name of
	* the MEee2gZ2qq class and the shared object where it is defined. */
	template <>
	struct ClassTraits<Herwig::MEee2gZ2qq>
	: public ClassTraitsBase<Herwig::MEee2gZ2qq> {
	/** Return a platform-independent class name */
	static string className() { return "Herwig::MEee2gZ2qq"; }
	/** Return the name(s) of the shared library (or libraries) be loaded to get
	* access to the MEee2gZ2qq class and any other class on which it depends
	* (except the base class). */
	static string library() { return "HwMELepton.so"; }
	};

	/** @endcond */

	}

	#endif /* HERWIG_MEee2gZ2qq_H */
	diff --git a/MatrixElement/Powheg/MEPP2VVPowheg.cc b/MatrixElement/Powheg/MEPP2VVPowheg.cc
	--- a/MatrixElement/Powheg/MEPP2VVPowheg.cc
	+++ b/MatrixElement/Powheg/MEPP2VVPowheg.cc
	@@ -1,5360 +1,5374 @@
	// -- C++ --
	//
	// MEPP2VVPowheg.cc is a part of Herwig++ - A multi-purpose Monte Carlo event generator
	// Copyright (C) 2002-2007 The Herwig Collaboration
	//
	// Herwig++ is licenced under version 2 of the GPL, see COPYING for details.
	// Please respect the MCnet academic guidelines, see GUIDELINES for details.
	//
	//
	// This is the implementation of the non-inlined, non-templated member
	// functions of the MEPP2VVPowheg class.
	//

	#include "MEPP2VVPowheg.h"
	#include "ThePEG/Interface/Switch.h"
	#include "ThePEG/Interface/Reference.h"
	#include "ThePEG/Interface/Parameter.h"
	#include "ThePEG/Interface/ClassDocumentation.h"
	#include "ThePEG/Persistency/PersistentOStream.h"
	#include "ThePEG/Persistency/PersistentIStream.h"
	#include "ThePEG/PDT/EnumParticles.h"
	#include "ThePEG/MatrixElement/Tree2toNDiagram.h"
	#include "ThePEG/Handlers/StandardXComb.h"
	#include "Herwig++/Models/StandardModel/StandardModel.h"
	#include "Herwig++/MatrixElement/HardVertex.h"
	#include "Herwig++/Decay/DecayMatrixElement.h"

	using namespace Herwig;

	MEPP2VVPowheg::MEPP2VVPowheg() :
	tiny(1.e-10), CF_(4./3.), TR_(0.5), NC_(3.),
	contrib_(1), channels_(0), nlo_alphaS_opt_(0) , fixed_alphaS_(0.1180346226),
	removebr_(1), scaleopt_(1), mu_F_(100.GeV), mu_UV_(100.GeV),
	ckm_(3,vector<Complex>(3,0.0)),
	helicityConservation_(true),
	realMESpinCorrelations_(true), power_(2.0),
	preqqbar_(3.7),preqg_(16.0),pregqbar_(11.0),
	b0_((11.-2./3.*5.)/4./Constants::pi),
	LambdaQCD_(91.118GeVexp(-1./2./((11.-2./3.*5.)/4./Constants::pi)/0.118)),
	min_pT_(2.*GeV){
	massOption(vector<unsigned int>(2,1));
	}

	void MEPP2VVPowheg::persistentOutput(PersistentOStream & os) const {
	os << contrib_ << channels_ << nlo_alphaS_opt_ << fixed_alphaS_
	<< removebr_ << scaleopt_ << ounit(mu_F_,GeV) << ounit(mu_UV_,GeV)
	<< ckm_ << helicityConservation_
	<< FFPvertex_ << FFWvertex_ << FFZvertex_ << WWWvertex_ << FFGvertex_
	<< realMESpinCorrelations_
	<< showerAlphaS_ << power_
	<< preqqbar_ << preqg_ << pregqbar_ << prefactor_
	<< b0_ << ounit(LambdaQCD_,GeV)
	<< ounit( min_pT_,GeV );
	}

	void MEPP2VVPowheg::persistentInput(PersistentIStream & is, int) {
	is >> contrib_ >> channels_ >> nlo_alphaS_opt_ >> fixed_alphaS_
	>> removebr_ >> scaleopt_ >> iunit(mu_F_,GeV) >> iunit(mu_UV_,GeV)
	>> ckm_ >> helicityConservation_
	>> FFPvertex_ >> FFWvertex_ >> FFZvertex_ >> WWWvertex_ >> FFGvertex_
	>> realMESpinCorrelations_
	>> showerAlphaS_ >> power_
	>> preqqbar_ >> preqg_ >> pregqbar_ >> prefactor_
	>> b0_ >> iunit(LambdaQCD_,GeV)
	>> iunit( min_pT_, GeV );
	}

	ClassDescription<MEPP2VVPowheg> MEPP2VVPowheg::initMEPP2VVPowheg;
	// Definition of the static class description member.

	void MEPP2VVPowheg::Init() {

	+ static ClassDocumentation<MEPP2VVPowheg> documentation
	+ ("The MEPP2VVPowheg class implements the NLO matrix elements for the production of"
	+ "pairs of electroweak vector bosons.",
	+ "The calcultaion of $W^+W^-$, $W^\\pm Z^0$ and $Z^0Z^0$ production"
	+ " in hadron collisions at next-to-leading order in the POWHEG scheme"
	+ " is described in \\cite{Hamilton:2010mb}.",
	+ "\\bibitem{Hamilton:2010mb}\n"
	+ " K.~Hamilton,\n"
	+ "%``A positive-weight next-to-leading order simulation of weak boson pair\n"
	+ "%production,''\n"
	+ "JHEP {\bf 1101} (2011) 009\n"
	+ "[arXiv:1009.5391 [hep-ph]].\n"
	+ "%%CITATION = JHEPA,1101,009;%%\n");
	+
	static Switch<MEPP2VVPowheg,unsigned int> interfaceContribution
	("Contribution",
	"Which contributions to the cross section to include",
	&MEPP2VVPowheg::contrib_, 1, false, false);
	static SwitchOption interfaceContributionLeadingOrder
	(interfaceContribution,
	"LeadingOrder",
	"Just generate the leading order cross section",
	0);
	static SwitchOption interfaceContributionPositiveNLO
	(interfaceContribution,
	"PositiveNLO",
	"Generate the positive contribution to the full NLO cross section",
	1);
	static SwitchOption interfaceContributionNegativeNLO
	(interfaceContribution,
	"NegativeNLO",
	"Generate the negative contribution to the full NLO cross section",
	2);

	static Switch<MEPP2VVPowheg,unsigned int> interfaceChannels
	("Channels",
	"Which channels to include in the cross section",
	&MEPP2VVPowheg::channels_, 0, false, false);
	static SwitchOption interfaceChannelsAll
	(interfaceChannels,
	"All",
	"All channels required for the full NLO cross section: qqb, qg, gqb",
	0);
	static SwitchOption interfaceChannelsAnnihilation
	(interfaceChannels,
	"Annihilation",
	"Only include the qqb annihilation channel, omitting qg and gqb channels",
	1);
	static SwitchOption interfaceChannelsCompton
	(interfaceChannels,
	"Compton",
	"Only include the qg and gqb compton channels, omitting all qqb processes",
	2);

	static Switch<MEPP2VVPowheg,unsigned int> interfaceNLOalphaSopt
	("NLOalphaSopt",
	"An option allowing you to supply a fixed value of alpha_S "
	"through the FixedNLOAlphaS interface.",
	&MEPP2VVPowheg::nlo_alphaS_opt_, 0, false, false);
	static SwitchOption interfaceNLOalphaSoptRunningAlphaS
	(interfaceNLOalphaSopt,
	"RunningAlphaS",
	"Use the usual running QCD coupling evaluated at scale mu_UV2()",
	0);
	static SwitchOption interfaceNLOalphaSoptFixedAlphaS
	(interfaceNLOalphaSopt,
	"FixedAlphaS",
	"Use a constant QCD coupling for comparison/debugging purposes",
	1);

	static Parameter<MEPP2VVPowheg,double> interfaceFixedNLOalphaS
	("FixedNLOalphaS",
	"The value of alphaS to use for the nlo weight if nlo_alphaS_opt_=1",
	&MEPP2VVPowheg::fixed_alphaS_, 0.1180346226, 0., 1.0,
	false, false, Interface::limited);

	static Switch<MEPP2VVPowheg,unsigned int> interfaceremovebr
	("removebr",
	"Whether to multiply the event weights by the MCFM branching ratios",
	&MEPP2VVPowheg::removebr_, 1, false, false);
	static SwitchOption interfaceProductionCrossSection
	(interfaceremovebr,
	"true",
	"Do not multiply in the branching ratios (default running)",
	1);
	static SwitchOption interfaceIncludeBRs
	(interfaceremovebr,
	"false",
	"Multiply by MCFM branching ratios for comparison/debugging purposes",
	0);

	static Switch<MEPP2VVPowheg,unsigned int> interfaceScaleOption
	("ScaleOption",
	"Option for running / fixing EW and QCD factorization & renormalization scales",
	&MEPP2VVPowheg::scaleopt_, 1, false, false);
	static SwitchOption interfaceDynamic
	(interfaceScaleOption,
	"Dynamic",
	"QCD factorization & renormalization scales are (mT(V1)+mT(V2))/2. "
	"EW scale is (mV1^2+mV2^2)/2 (similar to MCatNLO)",
	1);
	static SwitchOption interfaceFixed
	(interfaceScaleOption,
	"Fixed",
	"QCD factorization fixed to value by FactorizationScaleValue."
	"EW and QCD renormalization scales fixed by RenormalizationScaleValue.",
	2);

	static Parameter<MEPP2VVPowheg,Energy> interfaceFactorizationScaleValue
	("FactorizationScaleValue",
	"Value to use for the QCD factorization scale if fixed scales"
	"have been requested with the ScaleOption interface.",
	&MEPP2VVPowheg::mu_F_, GeV, 100.0GeV, 50.0GeV, 500.0*GeV,
	true, false, Interface::limited);

	static Parameter<MEPP2VVPowheg,Energy> interfaceRenormalizationScaleValue
	("RenormalizationScaleValue",
	"Value to use for the EW and QCD renormalization scales if fixed "
	"scales have been requested with the ScaleOption interface.",
	&MEPP2VVPowheg::mu_UV_, GeV, 100.0GeV, 50.0GeV, 500.0*GeV,
	true, false, Interface::limited);

	static Switch<MEPP2VVPowheg,bool> interfaceSpinCorrelations
	("SpinCorrelations",
	"Flag to select leading order spin correlations or a "
	"calculation taking into account the real NLO effects",
	&MEPP2VVPowheg::realMESpinCorrelations_, 1, false, false);
	static SwitchOption interfaceSpinCorrelationsLeadingOrder
	(interfaceSpinCorrelations,
	"LeadingOrder",
	"Decay bosons using a leading order 2->2 calculation of the "
	"production spin density matrix",
	0);
	static SwitchOption interfaceSpinCorrelationsRealNLO
	(interfaceSpinCorrelations,
	"RealNLO",
	"Decay bosons using a production spin density matrix which "
	"takes into account the effects of real radiation",
	1);

	static Reference<MEPP2VVPowheg,ShowerAlpha> interfaceCoupling
	("Coupling",
	"The object calculating the strong coupling constant",
	&MEPP2VVPowheg::showerAlphaS_, false, false, true, false, false);

	static Parameter<MEPP2VVPowheg,double> interfacePower
	("Power",
	"The power for the sampling of the matrix elements",
	&MEPP2VVPowheg::power_, 2.0, 1.0, 10.0,
	false, false, Interface::limited);

	static Parameter<MEPP2VVPowheg,double> interfacePrefactorqqbar
	("Prefactorqqbar",
	"The prefactor for the sampling of the q qbar channel",
	&MEPP2VVPowheg::preqqbar_, 5.0, 0.0, 1000.0,
	false, false, Interface::limited);

	static Parameter<MEPP2VVPowheg,double> interfacePrefactorqg
	("Prefactorqg",
	"The prefactor for the sampling of the q g channel",
	&MEPP2VVPowheg::preqg_, 3.0, 0.0, 1000.0,
	false, false, Interface::limited);

	static Parameter<MEPP2VVPowheg,double> interfacePrefactorgqbar
	("Prefactorgqbar",
	"The prefactor for the sampling of the g qbar channel",
	&MEPP2VVPowheg::pregqbar_, 3.0, 0.0, 1000.0,
	false, false, Interface::limited);

	static Parameter<MEPP2VVPowheg, Energy> interfacepTMin
	("minPt",
	"The pT cut on hardest emision generation"
	"2(1-Beta)exp(-sqr(intrinsicpT/RMS))/sqr(RMS)",
	&MEPP2VVPowheg::min_pT_, GeV, 2.GeV, ZERO, 100000.0GeV,
	false, false, Interface::limited);
	}

	Energy2 MEPP2VVPowheg::scale() const {
	// N.B. This scale is the electroweak scale!
	// It is used in the evaluation of the LO code
	// in the MEPP2VV base class. This means it
	// should appear in the denominator of the
	// NLOweight here and all other LO parts like
	// the function for the lumi ratio (Lhat). It
	// should also be used for evaluating any EW
	// parameters / vertices in the numerator.
	// The scaleopt_ == 1 "running" option is
	// chosen to be like the MC@NLO one (it ought
	// to be more like sHat instead?).
	return scaleopt_ == 1 ?
	// 0.5*(meMomenta()[2].m2()+meMomenta()[3].m2()) : sqr(mu_UV_);
	sHat() : sqr(mu_UV_);
	}

	Energy2 MEPP2VVPowheg::mu_F2() const {
	return scaleopt_ == 1 ?
	// ((H_.k1r()).m2()+k1r_perp2_lab_+(H_.k2r()).m2()+k2r_perp2_lab_)/2. : sqr(mu_F_);
	sHat() : sqr(mu_F_);
	}

	Energy2 MEPP2VVPowheg::mu_UV2() const {
	return scaleopt_ == 1 ?
	// ((H_.k1r()).m2()+k1r_perp2_lab_+(H_.k2r()).m2()+k2r_perp2_lab_)/2. : sqr(mu_UV_);
	sHat() : sqr(mu_UV_);
	}

	void MEPP2VVPowheg::doinit() {
	MEPP2VV::doinit();
	// get the vertices we need
	// get a pointer to the standard model object in the run
	static const tcHwSMPtr hwsm
	= dynamic_ptr_cast<tcHwSMPtr>(standardModel());
	if (!hwsm) throw InitException()
	<< "missing hwsm pointer in MEPP2VVPowheg::doinit()"
	<< Exception::abortnow;
	// get pointers to all required Vertex objects
	FFPvertex_ = hwsm->vertexFFP();
	FFZvertex_ = hwsm->vertexFFZ();
	WWWvertex_ = hwsm->vertexWWW();
	FFWvertex_ = hwsm->vertexFFW();
	FFGvertex_ = hwsm->vertexFFG();
	// get the ckm object
	Ptr<StandardCKM>::pointer
	theCKM=dynamic_ptr_cast<Ptr<StandardCKM>::pointer>(SM().CKM());
	if(!theCKM) throw InitException() << "MEPP2VVPowheg::doinit() "
	<< "the CKM object must be the Herwig one"
	<< Exception::runerror;
	unsigned int ix,iy;
	// get the CKM matrix (unsquared for interference)
	vector< vector<Complex > > CKM(theCKM->getUnsquaredMatrix(SM().families()));
	for(ix=0;ix<3;++ix){for(iy=0;iy<3;++iy){ckm_[ix][iy]=CKM[ix][iy];}}
	// insert the different prefactors in the vector for easy look up
	prefactor_.push_back(preqqbar_);
	prefactor_.push_back(preqg_);
	prefactor_.push_back(pregqbar_);
	}

	int MEPP2VVPowheg::nDim() const {
	int output = MEPP2VV::nDim();
	// See related comment in MEPP2VVPowheg::generateKinematics!
	if(contrib_>0) output += 2;
	return output;
	}

	bool MEPP2VVPowheg::generateKinematics(const double * r) {
	// N.B. A fix was made to make theta2 a radiative
	// variable in r4532. Originally theta2 was take to
	// be the azimuthal angle coming from the generation
	// of the Born kinematics inherited from MEPP2VV i.e.
	// before the change theta2 was a random number between
	// 0 and 2pi. On changing theta2 was set to be
	// theta2 = ((r+3)) 2.*Constants::pi;
	// and nDim returned if(contrib_>0) output += 3;
	// In the months following it was noticed that agreement
	// with MCFM was per mille at Tevatron energies but got
	// close to 1 percent for LHC energies (for all VV
	// processes). After searching back up the svn branch
	// running 2M events each time, the change was spotted
	// to occur on r4532. Changing:
	// if(contrib_>0) output += 3;
	// in ::nDim() and also,
	// xt = (*(r +nDim() -3));
	// y = ((r +nDim() -2)) 2. - 1.;
	// theta2 = ((r +nDim() -1)) 2.*Constants::pi;
	// did not fix the problem. The following code gives the
	// same good level of agreement at LHC and TVT:
	double xt( -999.);
	double y( -999.);
	double theta2( -999.);
	if(contrib_>0) {
	// Generate the radiative integration variables:
	xt = (*(r +nDim() -2));
	y = ((r +nDim() -1)) 2. - 1.;
	// KH 19th August - next line changed for phi in 0->pi not 0->2pi
	// theta2 = UseRandom::rnd() * 2.*Constants::pi;
	theta2 = UseRandom::rnd() *Constants::pi;
	}

	// Continue with lo matrix element code:
	bool output(MEPP2VV::generateKinematics(r));

	// Work out the kinematics for the leading order / virtual process
	// and also get the leading order luminosity function:
	getKinematics(xt,y,theta2);

	return output;
	}

	double MEPP2VVPowheg::me2() const {
	double output(0.0);
	useMe();
	output = MEPP2VV::me2();
	double mcfm_brs(1.);
	if(!removebr_) {
	switch(MEPP2VV::process()) {
	case 1: // W+(->e+,nu_e) W-(->e-,nu_ebar) (MCFM: 61 [nproc])
	mcfm_brs *= 0.109338816;
	mcfm_brs *= 0.109338816;
	break;
	case 2: // W+/-(mu+,nu_mu / mu-,nu_mubar) Z(nu_e,nu_ebar)
	// (MCFM: 72+77 [nproc])
	mcfm_brs *= 0.109338816;
	mcfm_brs *= 0.06839002;
	break;
	case 3: // Z(mu-,mu+) Z(e-,e+) (MCFM: 86 [nproc])
	mcfm_brs *= 0.034616433;
	mcfm_brs *= 0.034616433;
	mcfm_brs *= 2.; // as identical particle factor 1/2 is now obsolete.
	break;
	case 4: // W+(mu+,nu_mu) Z(nu_e,nu_ebar) (MCFM: 72 [nproc])
	mcfm_brs *= 0.109338816;
	mcfm_brs *= 0.06839002;
	break;
	case 5: // W-(mu-,nu_mubar) Z(nu_e,nu_ebar) (MCFM: 77 [nproc])
	mcfm_brs *= 0.109338816;
	mcfm_brs *= 0.06839002;
	break;
	}
	}

	// Store the value of the leading order squared matrix element:
	lo_me2_ = output;
	output *= NLOweight();
	output *= mcfm_brs;
	return output;
	}

	void MEPP2VVPowheg::getKinematics(double xt, double y, double theta2) {

	// In this member we want to get the lo_lumi_ as this is a
	// common denominator in the NLO weight. We want also the
	// bornVVKinematics object and all of the realVVKinematics
	// objects needed for the NLO weight.

	// Check if the W- is first in W+W- production. Already confirmed
	// mePartonData()[0] is a quark, and mePartonData()[1] is an antiquark.
	// We assume mePartonData[2] and mePartonData[3] are, respectively,
	// W+/- Z, W+/- W-/+, or Z Z.
	bool wminus_first(false);
	if((mePartonData()[2]->id()==-24)&&(mePartonData()[3]->id()==24))
	wminus_first=true;

	// Now get all data on the LO process needed for the NLO computation:

	// The +z hadron in the lab:
	hadron_A_=dynamic_ptr_cast<Ptr<BeamParticleData>::transient_const_pointer>
	(lastParticles().first->dataPtr());
	// The -z hadron in the lab:
	hadron_B_=dynamic_ptr_cast<Ptr<BeamParticleData>::transient_const_pointer>
	(lastParticles().second->dataPtr());

	// Leading order momentum fractions:
	double xa(lastX1()); // The +z momentum fraction in the lab.
	double xb(lastX2()); // The -z momentum fraction in the lab.

	// Particle data for incoming +z & -z QCD particles respectively:
	ab_ = lastPartons().first ->dataPtr(); // The +z momentum parton in the lab.
	bb_ = lastPartons().second->dataPtr(); // The -z momentum parton in the lab.

	// We checked TVT & LHC for all VV channels with 10K events:
	// lastParticles().first ->momentum().z() is always positive
	// lastParticles().second->momentum().z() is always negative
	// lastParticles().first ->momentum().z()*xa=lastPartons().first ->momentum().z() 1 in 10^6
	// lastParticles().second->momentum().z()*xb=lastPartons().second->momentum().z() 1 in 10^6

	// Set the quark and antiquark data pointers.
	quark_ = mePartonData()[0];
	antiquark_ = mePartonData()[1];
	if(quark_->id()<0) swap(quark_,antiquark_);

	// Now in _our_ calculation we basically define the +z axis as being
	// given by the direction of the incoming quark for q+qb & q+g processes
	// and the incoming gluon for g+qbar processes. So now we might need to
	// flip the values of hadron_A_, hadron_B_, ab_, bb_, xa, xb accordingly:
	if(ab_->id()!=quark_->id()) {
	swap(hadron_A_,hadron_B_);
	swap(ab_,bb_);
	swap(xa,xb);
	}
	// So hadron_A_ is the thing containing a quark (ab_) with momentum frac xa,
	// hadron_B_ is the thing containing an antiquark (bb_) with momentum frac xb.

	// Now get the partonic flux for the Born process:
	lo_lumi_ = hadron_A_->pdf()->xfx(hadron_A_,ab_,scale(),xa)/xa
	* hadron_B_->pdf()->xfx(hadron_B_,bb_,scale(),xb)/xb;

	// For W+W- events make sure k1 corresponds to the W+ momentum:
	if(MEPP2VV::process()==1&&wminus_first) swap(meMomenta()[2],meMomenta()[3]);

	// Create the object containing all 2->2 __kinematic__ information:
	B_ = bornVVKinematics(meMomenta(),xa,xb);
	// We checked that meMomenta()[0] (quark) is in the +z direction and meMomenta()[1]
	// is in the -z direction (antiquark).

	// Revert momentum swap in case meMomenta and mePartonData correlation
	// needs preserving for other things.
	if(MEPP2VV::process()==1&&wminus_first) swap(meMomenta()[2],meMomenta()[3]);

	// Check the Born kinematics objects is internally consistent:
	// B_.sanityCheck();

	// If we are going beyond leading order then lets calculate all of
	// the necessary real emission kinematics.
	if(contrib_>0) {
	// Soft limit of the 2->3 real emission kinematics:
	S_ = realVVKinematics(B_, 1., y, theta2);
	// Soft-collinear limit of the 2->3 kinematics (emission in +z direction):
	SCp_ = realVVKinematics(B_, 1., 1., theta2);
	// Soft-collinear limit of the 2->3 kinematics (emission in -z direction):
	SCm_ = realVVKinematics(B_, 1.,-1., theta2);
	// Collinear limit of the 2->3 kinematics (emission in +z direction):
	Cp_ = realVVKinematics(B_, xt, 1., theta2);
	// Collinear limit of the 2->3 kinematics (emission in -z direction):
	Cm_ = realVVKinematics(B_, xt,-1., theta2);
	// The resolved 2->3 real emission kinematics:
	H_ = realVVKinematics(B_, xt, y, theta2);

	// Borrowed from VVhardGenerator (lab momenta of k1,k2):
	Energy pT(sqrt(H_.pT2_in_lab()));
	LorentzRotation yzRotation;
	yzRotation.setRotateX(-atan2(pT/GeV,sqrt(B_.sb())/GeV));
	LorentzRotation boostFrompTisZero;
	boostFrompTisZero.setBoostY(-pT/sqrt(B_.sb()+pT*pT));
	LorentzRotation boostFromYisZero;
	boostFromYisZero.setBoostZ(tanh(B_.Yb()));
	k1r_perp2_lab_ = (boostFromYisZeroboostFrompTisZeroyzRotation*(H_.k1r())).perp2();
	k2r_perp2_lab_ = (boostFromYisZeroboostFrompTisZeroyzRotation*(H_.k2r())).perp2();

	// Check all the real kinematics objects are internally consistent:
	// S_.sanityCheck();
	// SCp_.sanityCheck();
	// SCm_.sanityCheck();
	// Cp_.sanityCheck();
	// Cm_.sanityCheck();
	// H_.sanityCheck();
	}

	return;
	}


	double MEPP2VVPowheg::NLOweight() const {
	// If only leading order is required return 1:
	if(contrib_==0) return lo_me()/lo_me2_;

	// Calculate alpha_S and alpha_S/(2*pi).
	alphaS_ = nlo_alphaS_opt_==1 ? fixed_alphaS_ : SM().alphaS(mu_UV2());
	double alsOn2pi(alphaS_/2./pi);

	// Particle data objects for the new plus and minus colliding partons.
	tcPDPtr gluon;
	gluon = getParticleData(ParticleID::g);

	// Get the all couplings.
	gW_ = sqrt(4.0piSM().alphaEM(scale())/SM().sin2ThetaW());
	sin2ThetaW_ = SM().sin2ThetaW();
	double cosThetaW(sqrt(1.-sin2ThetaW_));
	guL_ = gW_/2./cosThetaW( 1.-4./3.sin2ThetaW_);
	gdL_ = gW_/2./cosThetaW(-1.+2./3.sin2ThetaW_);
	guR_ = gW_/2./cosThetaW( -4./3.sin2ThetaW_);
	gdR_ = gW_/2./cosThetaW( +2./3.sin2ThetaW_);
	eZ_ = gW_*cosThetaW;
	eZ2_ = sqr(eZ_);

	// MCFM has gwsq = 0.4389585130009 -> gw = 0.662539442600115
	// Here we have gW_ = 0.662888
	// MCFM has xw = 0.22224653300000 -> sqrt(xw) = 0.471430306
	// Here we have 0.222247
	// MCFM has esq = 0.097557007645279 -> e = 0.31234117187024679
	// Here we have 4.0piSM().alphaEM(sqr(100.*GeV)) = 0.0976596

	// If the process is W-Z instead of W+Z we must transform these
	// couplings as follows, according to NPB 383(1992)3-44 Eq.3.23
	if(mePartonData()[2]->id()==-24&&mePartonData()[3]->id()==23) {
	swap(guL_,gdL_);
	eZ_ *= -1.;
	}

	// Get the CKM entry. Note that this code was debugged
	// considerably; the call to CKM(particle,particle)
	// did not appear to work, so we extract the elements
	// as follows below. The right numbers now appear to
	// to be associated with the right quarks.
	double Kij(-999.);
	// W+Z / W-Z
	if(abs(mePartonData()[2]->id())==24&&mePartonData()[3]->id()==23) {
	int up_id(-999),dn_id(-999);
	if(abs(quark_->id())%2==0&&abs(antiquark_->id())%2==1) {
	up_id = abs(quark_->id());
	dn_id = abs(antiquark_->id());
	}
	else if(abs(quark_->id())%2==1&&abs(antiquark_->id())%2==0) {
	up_id = abs(antiquark_->id());
	dn_id = abs(quark_->id());
	}
	else {
	cout << "MEPP2VVPowheg:" << endl;
	cout << "WZ needs an up and a down type quark as incoming!" << endl;
	}
	up_id /= 2;
	up_id -= 1;
	dn_id -= 1;
	dn_id /= 2;
	Kij = sqrt(SM().CKM(up_id,dn_id));
	}
	// W+W-
	else if(abs(mePartonData()[2]->id())==24&&abs(mePartonData()[3]->id())==24) {
	if(abs(quark_->id())%2==0&&abs(antiquark_->id())%2==0) {
	int up_ida(abs(quark_->id())/2-1);
	int up_idb(abs(antiquark_->id())/2-1);
	Kij = sqrt(std::norm( CKM(up_ida,0)*CKM(up_idb,0)
	+ CKM(up_ida,1)*CKM(up_idb,1)
	+ CKM(up_ida,2)*CKM(up_idb,2)));
	}
	else if(abs(quark_->id())%2==1&&abs(antiquark_->id())%2==1) {
	int dn_ida((abs(quark_->id())-1)/2);
	int dn_idb((abs(antiquark_->id())-1)/2);
	Kij = sqrt(std::norm( CKM(0,dn_ida)*CKM(0,dn_idb)
	+ CKM(1,dn_ida)*CKM(1,dn_idb)
	+ CKM(2,dn_ida)*CKM(2,dn_idb)));
	}
	else {
	cout << "MEPP2VVPowheg:" << endl;
	cout << "WW needs 2 down-type / 2 up-type!" << endl;
	}
	}
	// ZZ
	else if(mePartonData()[2]->id()==23&&mePartonData()[3]->id()==23) {
	Kij = 2.*sqrt(2.)/gW_;
	}
	else {
	cout << "MEPP2VVPowheg: incompatible final state particles!" << endl;
	}

	Fij2_ = sqr(gW_/2./sqrt(2.)*Kij);

	// Get the leading order matrix element (this is necessary!)
	M_Born_ = M_Born_WZ(B_);
	// // Get the regular part of the virtual correction (only needed for sanityCheck()!)
	// M_V_regular_ = M_V_regular(S_);
	// // Get the q + qbar real emission matrix element (only needed for sanityCheck()!)
	// t_u_M_R_qqb_ = t_u_M_R_qqb(H_);

	// Calculate the integrand
	double wgt(0.);
	double wqqb(0.);
	double wgqb(0.);
	double wqg(0.);
	double wqqbvirt(0.);
	double wqqbcollin(0.);
	double wqqbreal(0.);
	double wqgcollin(0.);
	double wqgreal(0.);
	double wgqbcollin(0.);
	double wgqbreal(0.);

	if(channels_==0\|\|channels_==1) {
	// q+qb
	wqqbvirt = Vtilde_universal(S_) + M_V_regular(S_)/lo_me2_;
	wqqbcollin = alsOn2pi*( Ctilde_Ltilde_qq_on_x(quark_,antiquark_,Cp_)
	+ Ctilde_Ltilde_qq_on_x(quark_,antiquark_,Cm_) );
	wqqbreal = alsOn2pi*Rtilde_Ltilde_qqb_on_x(quark_,antiquark_);
	wqqb = wqqbvirt + wqqbcollin + wqqbreal;
	}
	if(channels_==0\|\|channels_==2) {
	// q+g
	wqgcollin = alsOn2pi*Ctilde_Ltilde_gq_on_x(quark_,gluon,Cm_);
	wqgreal = alsOn2pi*Rtilde_Ltilde_qg_on_x(quark_,gluon);
	wqg = wqgreal + wqgcollin;
	// g+qb
	wgqbcollin = alsOn2pi*Ctilde_Ltilde_gq_on_x(gluon,antiquark_,Cp_);
	wgqbreal = alsOn2pi*Rtilde_Ltilde_gqb_on_x(gluon,antiquark_);
	wgqb = wgqbreal+wgqbcollin;
	}
	// total contribution
	wgt = 1.+(wqqb+wgqb+wqg);
	// If restricting to qg, gqb channels then subtract the LO contribution:
	if(channels_==2) wgt -= 1.;

	if(isnan(wgt)\|\|isinf(wgt)) {
	cout << "MEPP2VVPowheg:: NLO weight "
	<< "is bad: wgt = " << wgt << endl;
	cout << "MEPP2VVPowheg sanityCheck invoked!" << endl;
	cout << ab_->PDGName() << ", "
	<< bb_->PDGName() << ", "
	<< mePartonData()[2]->PDGName() << ", "
	<< mePartonData()[3]->PDGName() << endl;
	cout << "lo_me2_ - M_Born_ (rel) = "
	<< lo_me2_-M_Born_ << " ("
	<< (lo_me2_-M_Born_)/M_Born_ << ")\n";
	cout << "lo_me2_, M_Born_ " << lo_me2_ << ", " << M_Born_ << endl;
	cout << "xr = " << H_.xr() << " 1-xr = " << 1.-H_.xr() << " y = " << H_.y() << endl;
	cout << "tkr = " << H_.tkr()/GeV2 << " ukr = " << H_.ukr()/GeV2 << endl;
	cout << "root(sb) = " << sqrt(B_.sb())/GeV << endl;
	cout << "sb+tb+ub = "
	<< B_.sb()/GeV2 << " + "
	<< B_.tb()/GeV2 << " + " << B_.ub()/GeV2 << endl;
	cout << "sqrt(k12) " << sqrt(H_.k12r())/GeV << endl;
	cout << "sqrt(k22) " << sqrt(H_.k22r())/GeV << endl;
	cout << "sqr(Kij) " << Kij*Kij << endl;
	cout << "wqqbvirt " << wqqbvirt << endl;
	cout << "wqqbcollin " << wqqbcollin << endl;
	cout << "wqqbreal " << wqqbreal << endl;
	cout << "wqqb " << wqqb << endl;
	cout << "wqgcollin " << wqgcollin << endl;
	cout << "wqgreal " << wqgreal << endl;
	cout << "wqg " << wqg << endl;
	cout << "wgqbcollin " << wgqbcollin << endl;
	cout << "wgqbreal " << wgqbreal << endl;
	cout << "wgqb " << wgqb << endl;
	cout << "wgt " << wgt << endl;
	throw Exception() << "MEPP2VVPowheg:: NLO weight "
	<< "is bad: " << wgt
	<< Exception::eventerror;
	}
	return contrib_==1 ? max(0.,wgt) : max(0.,-wgt);
	}

	double MEPP2VVPowheg::Lhat_ab(tcPDPtr a, tcPDPtr b,
	realVVKinematics Kinematics) const {
	if(!(abs(a->id())<=6\|\|a->id()==21)\|\|!(abs(b->id())<=6\|\|b->id()==21))
	cout << "MEPP2VVPowheg::Lhat_ab: Error,"
	<< "particle a = " << a->PDGName() << ", "
	<< "particle b = " << b->PDGName() << endl;
	double nlo_lumi(-999.);
	double x1(Kinematics.x1r()),x2(Kinematics.x2r());
	nlo_lumi = (hadron_A_->pdf()->xfx(hadron_A_,a,mu_F2(),x1)/x1)
	* (hadron_B_->pdf()->xfx(hadron_B_,b,mu_F2(),x2)/x2);
	return nlo_lumi / lo_lumi_;
	}

	double MEPP2VVPowheg::Vtilde_universal(realVVKinematics S) const {
	double xbar_y = S.xbar();
	double y = S.y();
	double eta1b(S.bornVariables().eta1b());
	double eta2b(S.bornVariables().eta2b());
	Energy2 sb(S.s2r());
	return alphaS_/2./pi*CF_
	* ( log(sb/mu_F2())
	* (3. + 4.log(eta1b)+4.log(eta2b))
	+ 8.sqr(log(eta1b)) +8.sqr(log(eta2b))
	- 2.*sqr(pi)/3.
	)
	+ alphaS_/2./pi*CF_
	* ( 8./(1.+y)*log(sqrt(1.-xbar_y)/eta2b)
	+ 8./(1.-y)*log(sqrt(1.-xbar_y)/eta1b)
	);
	}

	double MEPP2VVPowheg::Ctilde_Ltilde_qq_on_x(tcPDPtr a, tcPDPtr b,
	realVVKinematics C) const {
	if(C.y()!= 1.&&C.y()!=-1.)
	cout << "\nCtilde_qq::y value not allowed.";
	if(C.y()== 1.&&!(abs(a->id())>0&&abs(a->id())<7))
	cout << "\nCtilde_qq::for Cqq^plus a must be a quark! id = "
	<< a->id() << "\n";
	if(C.y()==-1.&&!(abs(b->id())>0&&abs(b->id())<7))
	cout << "\nCtilde_qq::for Cqq^minus b must be a quark! id = "
	<< b->id() << "\n";
	double xt = C.xt();
	double x = C.xr();
	double etab = C.y() == 1. ? C.bornVariables().eta1b()
	: C.bornVariables().eta2b() ;
	Energy2 sb(C.s2r());
	if(fabs(1.-xt)<=tiny\|\|fabs(1.-H_.xr())<=tiny) return 0.;
	return ( ( (1./(1.-xt))log(sb/mu_F2()/x)+4.log(etab)/(1.-xt)
	+ 2.*log(1.-xt)/(1.-xt)
	)CF_(1.+sqr(x))
	+ sqr(etab)CF_(1.-x)
	)*Lhat_ab(a,b,C) / x
	- ( ( (1./(1.-xt))log(sb/mu_F2() )+4.log(etab)/(1.-xt)
	+ 2.*log(1.-xt)/(1.-xt)
	)CF_2.
	)*Lhat_ab(a,b,S_);
	}

	double MEPP2VVPowheg::Ctilde_Ltilde_gq_on_x(tcPDPtr a, tcPDPtr b,
	realVVKinematics C) const {
	if(C.y()!= 1.&&C.y()!=-1.)
	cout << "\nCtilde_gq::y value not allowed.";
	if(C.y()== 1.&&a->id()!=21)
	cout << "\nCtilde_gq::for Cgq^plus a must be a gluon! id = "
	<< a->id() << "\n";
	if(C.y()==-1.&&b->id()!=21)
	cout << "\nCtilde_gq::for Cgq^minus b must be a gluon! id = "
	<< b->id() << "\n";
	double xt = C.xt();
	double x = C.xr();
	double etab = C.y() == 1. ? C.bornVariables().eta1b()
	: C.bornVariables().eta2b() ;
	Energy2 sb(C.s2r());
	return ( ( (1./(1.-xt))log(sb/mu_F2()/x)+4.log(etab)/(1.-xt)
	+ 2.*log(1.-xt)/(1.-xt)
	)(1.-x)TR_*(sqr(x)+sqr(1.-x))
	+ sqr(etab)TR_2.x(1.-x)
	)*Lhat_ab(a,b,C) / x;
	}

	double MEPP2VVPowheg::Rtilde_Ltilde_qqb_on_x(tcPDPtr a , tcPDPtr b) const {
	if(!(abs(a->id())<=6\|\|a->id()==21)\|\|!(abs(b->id())<=6\|\|b->id()==21))
	cout << "MEPP2VVPowheg::Rtilde_Ltilde_qqb_on_x: Error,"
	<< "particle a = " << a->PDGName() << ", "
	<< "particle b = " << b->PDGName() << endl;
	double xt(H_.xt());
	double y(H_.y());
	Energy2 s(H_.sr());
	Energy2 sCp(Cp_.sr());
	Energy2 sCm(Cm_.sr());

	Energy2 t_u_M_R_qqb_H (t_u_M_R_qqb(H_ ));
	Energy2 t_u_M_R_qqb_Cp(t_u_M_R_qqb(Cp_));
	Energy2 t_u_M_R_qqb_Cm(t_u_M_R_qqb(Cm_));

	// Energy2 t_u_M_R_qqb_H (t_u_M_R_qqb_hel_amp(H_));
	// Energy2 t_u_M_R_qqb_Cp(8.pialphaS_*Cp_.sr()/Cp_.xr()
	// CF_(1.+sqr(Cp_.xr()))*lo_me2_);
	// Energy2 t_u_M_R_qqb_Cm(8.pialphaS_*Cm_.sr()/Cm_.xr()
	// CF_(1.+sqr(Cm_.xr()))*lo_me2_);

	int config(0);
	if(fabs(1.-xt)<=tiny\|\|fabs(1.-H_.xr())<=tiny) return 0.;
	if(fabs(1.-y )<=tiny) { t_u_M_R_qqb_H = t_u_M_R_qqb_Cp ; config = 1; }
	if(fabs(1.+y )<=tiny) { t_u_M_R_qqb_H = t_u_M_R_qqb_Cm ; config = -1; }
	if(fabs(H_.tkr()/s)<=tiny) { t_u_M_R_qqb_H = t_u_M_R_qqb_Cp ; config = 1; }
	if(fabs(H_.ukr()/s)<=tiny) { t_u_M_R_qqb_H = t_u_M_R_qqb_Cm ; config = -1; }

	if(config== 0)
	return
	( ( (t_u_M_R_qqb_HLhat_ab(a,b,H_)/s - t_u_M_R_qqb_CpLhat_ab(a,b,Cp_)/sCp)
	)*2./(1.-y)/(1.-xt)
	+ ( (t_u_M_R_qqb_HLhat_ab(a,b,H_)/s - t_u_M_R_qqb_CmLhat_ab(a,b,Cm_)/sCm)
	)*2./(1.+y)/(1.-xt)
	) / lo_me2_ / 8. / pi / alphaS_;
	else if(config== 1)
	return
	( (t_u_M_R_qqb_HLhat_ab(a,b,H_)/s - t_u_M_R_qqb_CmLhat_ab(a,b,Cm_)/sCm)
	)*2./(1.+y)/(1.-xt) / lo_me2_ / 8. / pi / alphaS_;
	else if(config==-1)
	return
	( (t_u_M_R_qqb_HLhat_ab(a,b,H_)/s - t_u_M_R_qqb_CpLhat_ab(a,b,Cp_)/sCp)
	)*2./(1.-y)/(1.-xt) / lo_me2_ / 8. / pi / alphaS_;
	else
	throw Exception()
	<< "MEPP2VVPowheg::Rtilde_Ltilde_qqb_on_x\n"
	<< "The configuration is not identified as hard / soft / fwd collinear or bwd collinear."
	<< "config = " << config << "\n"
	<< "xt = " << xt << " 1.-xt = " << 1.-xt << "\n"
	<< "y = " << y << " 1.-y = " << 1.-y << "\n"
	<< Exception::eventerror;
	}

	double MEPP2VVPowheg::Rtilde_Ltilde_gqb_on_x(tcPDPtr a , tcPDPtr b) const {
	if(!(abs(a->id())<=6\|\|a->id()==21)\|\|!(abs(b->id())<=6\|\|b->id()==21))
	cout << "MEPP2VVPowheg::Rtilde_Ltilde_gqb_on_x: Error,"
	<< "particle a = " << a->PDGName() << ", "
	<< "particle b = " << b->PDGName() << endl;
	double xt(H_.xt());
	double y(H_.y());
	Energy2 s(H_.sr());
	Energy2 sCp(Cp_.sr());
	Energy2 sCm(Cm_.sr());

	Energy2 t_u_M_R_gqb_H (t_u_M_R_gqb(H_ ));
	Energy2 t_u_M_R_gqb_Cp(t_u_M_R_gqb(Cp_));
	Energy2 t_u_M_R_gqb_Cm(t_u_M_R_gqb(Cm_));

	// Energy2 t_u_M_R_gqb_H (t_u_M_R_gqb_hel_amp(H_));
	// Energy2 t_u_M_R_gqb_Cp(8.pialphaS_Cp_.sr()/Cp_.xr()(1.-Cp_.xr())
	// TR_(sqr(Cp_.xr())+sqr(1.-Cp_.xr()))*lo_me2_);
	// Energy2 t_u_M_R_gqb_Cm(t_u_M_R_gqb(Cm_));
	// // Energy2 t_u_M_R_gqb_Cm(t_u_M_R_gqb_hel_amp(Cm_));

	int config(0);
	if(fabs(1.-xt)<=tiny\|\|fabs(1.-H_.xr())<=tiny) return 0.;
	if(fabs(1.-y )<=tiny) { t_u_M_R_gqb_H = t_u_M_R_gqb_Cp ; config = 1; }
	if(fabs(1.+y )<=tiny) { t_u_M_R_gqb_H = t_u_M_R_gqb_Cm ; config = -1; }
	if(fabs(H_.tkr()/s)<=tiny) { t_u_M_R_gqb_H = t_u_M_R_gqb_Cp ; config = 1; }
	if(fabs(H_.ukr()/s)<=tiny) { t_u_M_R_gqb_H = t_u_M_R_gqb_Cm ; config = -1; }

	if(config== 0)
	return
	( ( (t_u_M_R_gqb_HLhat_ab(a,b,H_)/s - t_u_M_R_gqb_CpLhat_ab(a,b,Cp_)/sCp)
	)*2./(1.-y)/(1.-xt)
	+ ( (t_u_M_R_gqb_HLhat_ab(a,b,H_)/s - t_u_M_R_gqb_CmLhat_ab(a,b,Cm_)/sCm)
	)*2./(1.+y)/(1.-xt)
	) / lo_me2_ / 8. / pi / alphaS_;
	else if(config== 1)
	return
	( (t_u_M_R_gqb_HLhat_ab(a,b,H_)/s - t_u_M_R_gqb_CmLhat_ab(a,b,Cm_)/sCm)
	)*2./(1.+y)/(1.-xt) / lo_me2_ / 8. / pi / alphaS_;
	else if(config==-1)
	return
	( (t_u_M_R_gqb_HLhat_ab(a,b,H_)/s - t_u_M_R_gqb_CpLhat_ab(a,b,Cp_)/sCp)
	)*2./(1.-y)/(1.-xt) / lo_me2_ / 8. / pi / alphaS_;
	else
	throw Exception()
	<< "MEPP2VVPowheg::Rtilde_Ltilde_gqb_on_x\n"
	<< "The configuration is not identified as hard / soft / fwd collinear or bwd collinear."
	<< "config = " << config << "\n"
	<< "xt = " << xt << " 1.-xt = " << 1.-xt << "\n"
	<< "y = " << y << " 1.-y = " << 1.-y << "\n"
	<< Exception::eventerror;
	}

	double MEPP2VVPowheg::Rtilde_Ltilde_qg_on_x(tcPDPtr a , tcPDPtr b) const {
	if(!(abs(a->id())<=6\|\|a->id()==21)\|\|!(abs(b->id())<=6\|\|b->id()==21))
	cout << "MEPP2VVPowheg::Rtilde_Ltilde_qg_on_x: Error,"
	<< "particle a = " << a->PDGName() << ", "
	<< "particle b = " << b->PDGName() << endl;
	double xt(H_.xt());
	double y(H_.y());
	Energy2 s(H_.sr());
	Energy2 sCp(Cp_.sr());
	Energy2 sCm(Cm_.sr());

	Energy2 t_u_M_R_qg_H (t_u_M_R_qg(H_ ));
	Energy2 t_u_M_R_qg_Cp(t_u_M_R_qg(Cp_));
	Energy2 t_u_M_R_qg_Cm(t_u_M_R_qg(Cm_));

	// Energy2 t_u_M_R_qg_H (t_u_M_R_qg_hel_amp(H_));
	// Energy2 t_u_M_R_qg_Cp(t_u_M_R_qg(Cp_));
	// // Energy2 t_u_M_R_qg_Cp(t_u_M_R_qg_hel_amp(Cp_));
	// Energy2 t_u_M_R_qg_Cm(8.pialphaS_Cm_.sr()/Cm_.xr()(1.-Cm_.xr())
	// TR_(sqr(Cm_.xr())+sqr(1.-Cm_.xr()))*lo_me2_);

	int config(0);
	if(fabs(1.-xt)<=tiny\|\|fabs(1.-H_.xr())<=tiny) return 0.;
	if(fabs(1.-y )<=tiny) { t_u_M_R_qg_H = t_u_M_R_qg_Cp ; config = 1; }
	if(fabs(1.+y )<=tiny) { t_u_M_R_qg_H = t_u_M_R_qg_Cm ; config = -1; }
	if(fabs(H_.tkr()/s)<=tiny) { t_u_M_R_qg_H = t_u_M_R_qg_Cp ; config = 1; }
	if(fabs(H_.ukr()/s)<=tiny) { t_u_M_R_qg_H = t_u_M_R_qg_Cm ; config = -1; }

	if(config== 0)
	return
	( ( (t_u_M_R_qg_HLhat_ab(a,b,H_)/s - t_u_M_R_qg_CpLhat_ab(a,b,Cp_)/sCp)
	)*2./(1.-y)/(1.-xt)
	+ ( (t_u_M_R_qg_HLhat_ab(a,b,H_)/s - t_u_M_R_qg_CmLhat_ab(a,b,Cm_)/sCm)
	)*2./(1.+y)/(1.-xt)
	) / lo_me2_ / 8. / pi / alphaS_;
	else if(config== 1)
	return
	( (t_u_M_R_qg_HLhat_ab(a,b,H_)/s - t_u_M_R_qg_CmLhat_ab(a,b,Cm_)/sCm)
	)*2./(1.+y)/(1.-xt) / lo_me2_ / 8. / pi / alphaS_;
	else if(config==-1)
	return
	( (t_u_M_R_qg_HLhat_ab(a,b,H_)/s - t_u_M_R_qg_CpLhat_ab(a,b,Cp_)/sCp)
	)*2./(1.-y)/(1.-xt) / lo_me2_ / 8. / pi / alphaS_;
	else
	throw Exception()
	<< "MEPP2VVPowheg::Rtilde_Ltilde_qg_on_x\n"
	<< "The configuration is not identified as hard / soft / fwd collinear or bwd collinear."
	<< "config = " << config << "\n"
	<< "xt = " << xt << " 1.-xt = " << 1.-xt << "\n"
	<< "y = " << y << " 1.-y = " << 1.-y << "\n"
	<< Exception::eventerror;
	}

	/***************************************************************************/
	// The following three functions are identically \tilde{I}_{4,t},
	// \tilde{I}_{3,WZ} and \tilde{I}_{3,W} given in Eqs. B.8,B.9,B.10
	// of NPB 383(1992)3-44, respectively. They are related to / derived
	// from the loop integrals in Eqs. A.3, A.5 and A.8 of the same paper.
	InvEnergy4 TildeI4t(Energy2 s, Energy2 t, Energy2 mW2, Energy2 mZ2);
	InvEnergy2 TildeI3WZ(Energy2 s, Energy2 mW2, Energy2 mZ2, double beta);
	InvEnergy2 TildeI3W(Energy2 s, Energy2 t, Energy2 mW2);

	/***************************************************************************/
	// The following six functions are identically I_{dd}^{(1)}, I_{ud}^{(1)},
	// I_{uu}^{(1)}, F_{u}^{(1)}, F_{d}^{(1)}, H^{(1)} from Eqs. B.4, B.5, B.3,
	// B.3, B.6, B.7 of NPB 383(1992)3-44, respectively. They make up the
	// one-loop matrix element. Ixx functions correspond to the graphs
	// with no TGC, Fx functions are due to non-TGC graphs interfering
	// with TGC graphs, while the H function is due purely to TGC graphs.
	double Idd1(Energy2 s,Energy2 t,Energy2 u,Energy2 mW2,Energy2 mZ2,double beta);
	double Iud1(Energy2 s,Energy2 t,Energy2 u,Energy2 mW2,Energy2 mZ2,double beta);
	double Iuu1(Energy2 s,Energy2 t,Energy2 u,Energy2 mW2,Energy2 mZ2,double beta);
	Energy2 Fu1(Energy2 s,Energy2 t,Energy2 u,Energy2 mW2,Energy2 mZ2,double beta);
	Energy2 Fd1(Energy2 s,Energy2 t,Energy2 u,Energy2 mW2,Energy2 mZ2,double beta);
	Energy4 H1 (Energy2 s,Energy2 t,Energy2 u,Energy2 mW2,Energy2 mZ2);

	/***************************************************************************/
	// M_V_Regular is the regular part of the one-loop matrix element
	// exactly as defined in Eqs. B.1 and B.2 of of NPB 383(1992)3-44.
	double MEPP2VVPowheg::M_V_regular(realVVKinematics S) const {
	Energy2 s(S.bornVariables().sb());
	Energy2 t(S.bornVariables().tb());
	Energy2 u(S.bornVariables().ub());
	Energy2 mW2(S.k12r()); // N.B. the diboson masses are preserved in getting
	Energy2 mZ2(S.k22r()); // the 2->2 from the 2->3 kinematics.
	double beta(S.betaxr()); // N.B. for x=1 \beta_x=\beta in NPB 383(1992)3-44.

	double cosThetaW(sqrt(1.-sin2ThetaW_));
	double eZ2(eZ2_);
	double eZ(eZ_);
	double gdL(gdL_);
	double guL(guL_);
	double gdR(gdR_);
	double guR(guR_);

	// W+W-
	if(abs(mePartonData()[2]->id())==24&&abs(mePartonData()[3]->id())==24) {
	double e2(sqr(gW_)*sin2ThetaW_);
	if(abs(quark_->id())%2==0&&abs(antiquark_->id())%2==0) {
	// N.B. OLD eZ used to calculate new eZ2 then new eZ is set!
	if(quark_->id()==-antiquark_->id()) {
	eZ2 = 1./2.*sqr(s-mW2)/Fij2_
	* (e2e2/s/s(sqr( 2./3.+eZ(guL+guR)/2./e2s/(s-mW2/sqr(cosThetaW)))
	+sqr( eZ(guL-guR)/2./e2s/(s-mW2/sqr(cosThetaW))))
	);
	eZ = -1./2./Fij2_/(gW_gW_/4./sqrt(Fij2_))(s-mW2)
	* (gW_gW_e2/4./s ( 2./3.+2.eZguL/2./e2s/(s-mW2/sqr(cosThetaW))));
	} else {
	eZ2 =0.;
	eZ =0.;
	}
	gdL = gW_/sqrt(2.);
	guL = 0.;
	}
	else if(abs(quark_->id())%2==1&&abs(antiquark_->id())%2==1) {
	// N.B. OLD eZ used to calculate new eZ2 then new eZ is set!
	if(quark_->id()==-antiquark_->id()) {
	eZ2 = 1./2.*sqr(s-mW2)/Fij2_
	* (e2e2/s/s(sqr(-1./3.+eZ(gdL+gdR)/2./e2s/(s-mW2/sqr(cosThetaW)))
	+sqr( eZ(gdL-gdR)/2./e2s/(s-mW2/sqr(cosThetaW))))
	);
	eZ = -1./2./Fij2_/(gW_gW_/4./sqrt(Fij2_))(s-mW2)
	* (gW_gW_e2/4./s (-1./3.+2.eZgdL/2./e2s/(s-mW2/sqr(cosThetaW))));
	} else {
	eZ2 =0.;
	eZ =0.;
	}
	guL = gW_/sqrt(2.);
	gdL = 0.;
	}
	}
	// ZZ
	else if(mePartonData()[2]->id()==23&&mePartonData()[3]->id()==23) {
	eZ = 0.;
	eZ2 = 0.;
	double gV2,gA2;
	gV2 = sqr(guL/2.-gW_/2./cosThetaW2./3.sin2ThetaW_);
	gA2 = sqr(guL/2.+gW_/2./cosThetaW2./3.sin2ThetaW_);
	guL = sqrt(gV2gV2+gA2gA2+6.gA2gV2)/2.;
	gV2 = sqr(gdL/2.+gW_/2./cosThetaW1./3.sin2ThetaW_);
	gA2 = sqr(gdL/2.-gW_/2./cosThetaW1./3.sin2ThetaW_);
	gdL = sqrt(gV2gV2+gA2gA2+6.gA2gV2)/2.;
	if(abs(quark_->id())%2==0&&abs(antiquark_->id())%2==0) gdL = guL;
	else if(abs(quark_->id())%2==1&&abs(antiquark_->id())%2==1) guL = gdL;
	else {
	cout << "MEPP2VVPowheg:" << endl;
	cout << "ZZ needs 2 down-type / 2 up-type!" << endl;
	}
	}

	return 4.pialphaS_Fij2_CF_(1./sqr(4.pi))/NC_
	* ( gdLgdLIdd1(s,t,u,mW2,mZ2,beta)
	+ gdLguLIud1(s,t,u,mW2,mZ2,beta)
	+ guLguLIuu1(s,t,u,mW2,mZ2,beta)
	- eZ/(s-mW2) * ( gdL*Fd1(s,t,u,mW2,mZ2,beta)
	- guL*Fu1(s,t,u,mW2,mZ2,beta)
	)
	+ eZ2/sqr(s-mW2) * H1(s,t,u,mW2,mZ2)
	);
	}

	/***************************************************************************/
	InvEnergy4 TildeI4t(Energy2 s, Energy2 t, Energy2 mW2, Energy2 mZ2) {
	double sqrBrackets;
	sqrBrackets = ( sqr(log(-t/mW2))/2.+log(-t/mW2)*log(-t/mZ2)/2.
	- 2.log(-t/mW2)log((mW2-t)/mW2)-2.*ReLi2(t/mW2)
	);

	swap(mW2,mZ2);
	sqrBrackets+= ( sqr(log(-t/mW2))/2.+log(-t/mW2)*log(-t/mZ2)/2.
	- 2.log(-t/mW2)log((mW2-t)/mW2)-2.*ReLi2(t/mW2)
	);
	swap(mW2,mZ2);

	return sqrBrackets/s/t;
	}

	InvEnergy2 TildeI3WZ(Energy2 s, Energy2 mW2, Energy2 mZ2, double beta) {
	Energy2 sig(mZ2+mW2);
	Energy2 del(mZ2-mW2);
	double sqrBrackets ;
	sqrBrackets = ( ReLi2(2.mW2/(sig-del(del/s+beta)))
	+ ReLi2((1.-del/s+beta)/2.)
	+ sqr(log((1.-del/s+beta)/2.))/2.
	+ log((1.-del/s-beta)/2.)*log((1.+del/s-beta)/2.)
	);

	beta *= -1;
	sqrBrackets -= ( ReLi2(2.mW2/(sig-del(del/s+beta)))
	+ ReLi2((1.-del/s+beta)/2.)
	+ sqr(log((1.-del/s+beta)/2.))/2.
	+ log((1.-del/s-beta)/2.)*log((1.+del/s-beta)/2.)
	);
	beta *= -1;

	swap(mW2,mZ2);
	del *= -1.;
	sqrBrackets += ( ReLi2(2.mW2/(sig-del(del/s+beta)))
	+ ReLi2((1.-del/s+beta)/2.)
	+ sqr(log((1.-del/s+beta)/2.))/2.
	+ log((1.-del/s-beta)/2.)*log((1.+del/s-beta)/2.)
	);
	swap(mW2,mZ2);
	del *= -1.;

	beta *= -1;
	swap(mW2,mZ2);
	del *= -1.;
	sqrBrackets -= ( ReLi2(2.mW2/(sig-del(del/s+beta)))
	+ ReLi2((1.-del/s+beta)/2.)
	+ sqr(log((1.-del/s+beta)/2.))/2.
	+ log((1.-del/s-beta)/2.)*log((1.+del/s-beta)/2.)
	);
	beta *= -1;
	swap(mW2,mZ2);
	del *= -1.;

	return sqrBrackets/s/beta;
	}

	InvEnergy2 TildeI3W(Energy2 s, Energy2 t, Energy2 mW2) {
	return
	1./(mW2-t)*(sqr(log(mW2/s))/2.-sqr(log(-t/s))/2.-sqr(pi)/2.);
	}

	/***************************************************************************/
	double Idd1(Energy2 s, Energy2 t, Energy2 u, Energy2 mW2, Energy2 mZ2, double beta) {
	Energy2 sig(mZ2+mW2);
	Energy2 del(mZ2-mW2);
	double Val(0.);

	Val += 2.(22.tt+t(19.s-18.sig)+18.mW2mZ2)/t/t
	- 8.(ut+2ssig)/mW2/mZ2
	- 2.*sqr(t-u)/t/s/sqr(beta);

	Val += +( 2.(8.tt+4.t(s-3.sig)+4sqr(sig)-5.ssig+ss)/t/s/sqr(beta)
	+ 4.(t(3.u+s)-3.mW2*mZ2)/t/t
	+ 6.(t+u)sqr(t-u)/t/s/s/sqr(sqr(beta))
	)*log(-t/s);

	Val += +( ( 8.tt(-2.s+del)+8.t(-ss+3.ssig-2.del*sig)
	- 2.(s-sig)(ss-4.ssig+3.del*sig)
	)/t/s/s/beta/beta
	+ 16.s(t-mZ2)/(t(u+s)-mW2mZ2)
	+ 2.(4.tt+t(10.s-3.mZ2-9.mW2)+12.mW2*mZ2)/t/t
	-6.(s-del)(t+u)*sqr(t-u)/t/s/s/s/sqr(sqr(beta))
	)*log(-t/mW2);

	Val += ( - ( 4.tt(2.sig-3.*s)
	- 4.t(s-sig)(2.s-3.*sig)
	- 2.(s-2.sig)*sqr(s-sig)
	)/t/s/beta/beta
	+ ( 4.sigt-3.ss+4.ssig
	- 4.(mW2mW2+mZ2*mZ2)
	)/t
	- 3.sqr(tt-u*u)/t/s/s/sqr(sqr(beta))
	)*TildeI3WZ(s,mW2,mZ2,beta);

	Val += +( 4.(tu+2.ssig)/3./mW2/mZ2 - 4.(t-2.u)/3./t
	)pipi;

	Val += -( 4.s(tu-2.mW2*mZ2)/t
	)*TildeI4t(s,t,mW2,mZ2);

	Val += ( 8.(t-mW2)(ut-2.mW2*mZ2)/t/t
	)*TildeI3W(s,t,mW2);

	swap(mW2,mZ2);
	del *= -1;
	Val += 2.(22.tt+t(19.s-18.sig)+18.mW2mZ2)/t/t
	- 8.(ut+2ssig)/mW2/mZ2
	- 2.*sqr(t-u)/t/s/sqr(beta);

	Val += +( 2.(8.tt+4.t(s-3.sig)+4sqr(sig)-5.ssig+ss)/t/s/sqr(beta)
	+ 4.(t(3.u+s)-3.mW2*mZ2)/t/t
	+ 6.(t+u)sqr(t-u)/t/s/s/sqr(sqr(beta))
	)*log(-t/s);

	Val += +( ( 8.tt(-2.s+del)+8.t(-ss+3.ssig-2.del*sig)
	- 2.(s-sig)(ss-4.ssig+3.del*sig)
	)/t/s/s/beta/beta
	+ 16.s(t-mZ2)/(t(u+s)-mW2mZ2)
	+ 2.(4.tt+t(10.s-3.mZ2-9.mW2)+12.mW2*mZ2)/t/t
	-6.(s-del)(t+u)*sqr(t-u)/t/s/s/s/sqr(sqr(beta))
	)*log(-t/mW2);

	Val += ( - ( 4.tt(2.sig-3.*s)
	- 4.t(s-sig)(2.s-3.*sig)
	- 2.(s-2.sig)*sqr(s-sig)
	)/t/s/beta/beta
	+ ( 4.sigt-3.ss+4.ssig
	- 4.(mW2mW2+mZ2*mZ2)
	)/t
	- 3.sqr(tt-u*u)/t/s/s/sqr(sqr(beta))
	)*TildeI3WZ(s,mW2,mZ2,beta);

	Val += +( 4.(tu+2.ssig)/3./mW2/mZ2 - 4.(t-2.u)/3./t
	)pipi;

	Val += -( 4.s(tu-2.mW2*mZ2)/t
	)*TildeI4t(s,t,mW2,mZ2);

	Val += ( 8.(t-mW2)(ut-2.mW2*mZ2)/t/t
	)*TildeI3W(s,t,mW2);
	swap(mW2,mZ2);
	del *= -1;

	return Val;
	}

	/***************************************************************************/
	double Iud1(Energy2 s, Energy2 t, Energy2 u, Energy2 mW2, Energy2 mZ2, double beta) {
	Energy2 sig(mZ2+mW2);
	Energy2 del(mZ2-mW2);
	double Val(0.);

	Val += 2.(4.tt+t(9.s-4.sig)-18.ssig)/t/u
	+ 8.(tu+2.ssig)/mW2/mZ2
	+ 4.ss(2.t-sig)/u/(mW2mZ2-t(u+s))
	- 2.*sqr(t-u)/u/s/sqr(beta);

	Val += ( 2.(8.tt-4.t(s+3.sig)-(s-sig)(3.s+4.*sig))/u/s/sqr(beta)
	+ 6.(t+u)sqr(t-u)/u/s/s/sqr(sqr(beta))
	- 12.s(t-sig)/t/u
	)*log(-t/s);

	Val += ( (2./u/s/s/sqr(beta))( 4.tt(-2.*s+del)
	+ 4.t(ss+s(mZ2+5.mW2)-2.sig*del)
	+ (s-sig)(3.ss+8.mW2s-3.sig*del)
	)
	+ (2.t(18.s+3.mW2+mZ2)-24.ssig)/t/u
	- 8.s(2.tt-t(3.s+4.mZ2+2.mW2)+2.mZ2(s+sig))
	/u/(mW2mZ2-t(u+s))
	- 8.sst(2.t-sig)(t-mZ2)/u/sqr(mW2mZ2-t(u+s))
	+ 6.(s-del)(s-sig)*sqr(t-u)/u/s/s/s/sqr(sqr(beta))
	)*log(-t/mW2);

	Val += ( -2.(2.tt(2.sig-3.s)+6.sigt(s-sig)+sqr(s-sig)(s+2.*sig))
	/u/s/sqr(beta)
	+3.s(4.t-4.sig-s)/u
	-3.sqr(s-sig)sqr(t-u)/u/s/s/sqr(sqr(beta))
	)*TildeI3WZ(s,mW2,mZ2,beta);

	Val += ( 4.(u+4.s)/3./u - 4.(ut+2.ssig)/3./mW2/mZ2
	)pipi;

	Val += -( 16.s(t-sig)*(t-mW2)/t/u
	)*TildeI3W(s,t,mW2);

	Val += ( 8.ss*(t-sig)/u
	)*TildeI4t(s,t,mW2,mZ2);

	swap(t,u);
	Val += 2.(4.tt+t(9.s-4.sig)-18.ssig)/t/u
	+ 8.(tu+2.ssig)/mW2/mZ2
	+ 4.ss(2.t-sig)/u/(mW2mZ2-t(u+s))
	- 2.*sqr(t-u)/u/s/sqr(beta);

	Val += ( 2.(8.tt-4.t(s+3.sig)-(s-sig)(3.s+4.*sig))/u/s/sqr(beta)
	+ 6.(t+u)sqr(t-u)/u/s/s/sqr(sqr(beta))
	- 12.s(t-sig)/t/u
	)*log(-t/s);

	Val += ( (2./u/s/s/sqr(beta))( 4.tt(-2.*s+del)
	+ 4.t(ss+s(mZ2+5.mW2)-2.sig*del)
	+ (s-sig)(3.ss+8.mW2s-3.sig*del)
	)
	+ (2.t(18.s+3.mW2+mZ2)-24.ssig)/t/u
	- 8.s(2.tt-t(3.s+4.mZ2+2.mW2)+2.mZ2(s+sig))
	/u/(mW2mZ2-t(u+s))
	- 8.sst(2.t-sig)(t-mZ2)/u/sqr(mW2mZ2-t(u+s))
	+ 6.(s-del)(s-sig)*sqr(t-u)/u/s/s/s/sqr(sqr(beta))
	)*log(-t/mW2);

	Val += ( -2.(2.tt(2.sig-3.s)+6.sigt(s-sig)+sqr(s-sig)(s+2.*sig))
	/u/s/sqr(beta)
	+3.s(4.t-4.sig-s)/u
	-3.sqr(s-sig)sqr(t-u)/u/s/s/sqr(sqr(beta))
	)*TildeI3WZ(s,mW2,mZ2,beta);

	Val += ( 4.(u+4.s)/3./u - 4.(ut+2.ssig)/3./mW2/mZ2
	)pipi;

	Val += -( 16.s(t-sig)*(t-mW2)/t/u
	)*TildeI3W(s,t,mW2);

	Val += ( 8.ss*(t-sig)/u
	)*TildeI4t(s,t,mW2,mZ2);
	swap(t,u);

	swap(mW2,mZ2);
	del *= -1;
	Val += 2.(4.tt+t(9.s-4.sig)-18.ssig)/t/u
	+ 8.(tu+2.ssig)/mW2/mZ2
	+ 4.ss(2.t-sig)/u/(mW2mZ2-t(u+s))
	- 2.*sqr(t-u)/u/s/sqr(beta);

	Val += ( 2.(8.tt-4.t(s+3.sig)-(s-sig)(3.s+4.*sig))/u/s/sqr(beta)
	+ 6.(t+u)sqr(t-u)/u/s/s/sqr(sqr(beta))
	- 12.s(t-sig)/t/u
	)*log(-t/s);

	Val += ( (2./u/s/s/sqr(beta))( 4.tt(-2.*s+del)
	+ 4.t(ss+s(mZ2+5.mW2)-2.sig*del)
	+ (s-sig)(3.ss+8.mW2s-3.sig*del)
	)
	+ (2.t(18.s+3.mW2+mZ2)-24.ssig)/t/u
	- 8.s(2.tt-t(3.s+4.mZ2+2.mW2)+2.mZ2(s+sig))
	/u/(mW2mZ2-t(u+s))
	- 8.sst(2.t-sig)(t-mZ2)/u/sqr(mW2mZ2-t(u+s))
	+ 6.(s-del)(s-sig)*sqr(t-u)/u/s/s/s/sqr(sqr(beta))
	)*log(-t/mW2);

	Val += ( -2.(2.tt(2.sig-3.s)+6.sigt(s-sig)+sqr(s-sig)(s+2.*sig))
	/u/s/sqr(beta)
	+3.s(4.t-4.sig-s)/u
	-3.sqr(s-sig)sqr(t-u)/u/s/s/sqr(sqr(beta))
	)*TildeI3WZ(s,mW2,mZ2,beta);

	Val += ( 4.(u+4.s)/3./u - 4.(ut+2.ssig)/3./mW2/mZ2
	)pipi;

	Val += -( 16.s(t-sig)*(t-mW2)/t/u
	)*TildeI3W(s,t,mW2);

	Val += ( 8.ss*(t-sig)/u
	)*TildeI4t(s,t,mW2,mZ2);
	swap(mW2,mZ2);
	del *= -1;

	swap(t,u);
	swap(mW2,mZ2);
	del *= -1;
	Val += 2.(4.tt+t(9.s-4.sig)-18.ssig)/t/u
	+ 8.(tu+2.ssig)/mW2/mZ2
	+ 4.ss(2.t-sig)/u/(mW2mZ2-t(u+s))
	- 2.*sqr(t-u)/u/s/sqr(beta);

	Val += ( 2.(8.tt-4.t(s+3.sig)-(s-sig)(3.s+4.*sig))/u/s/sqr(beta)
	+ 6.(t+u)sqr(t-u)/u/s/s/sqr(sqr(beta))
	- 12.s(t-sig)/t/u
	)*log(-t/s);

	Val += ( (2./u/s/s/sqr(beta))( 4.tt(-2.*s+del)
	+ 4.t(ss+s(mZ2+5.mW2)-2.sig*del)
	+ (s-sig)(3.ss+8.mW2s-3.sig*del)
	)
	+ (2.t(18.s+3.mW2+mZ2)-24.ssig)/t/u
	- 8.s(2.tt-t(3.s+4.mZ2+2.mW2)+2.mZ2(s+sig))
	/u/(mW2mZ2-t(u+s))
	- 8.sst(2.t-sig)(t-mZ2)/u/sqr(mW2mZ2-t(u+s))
	+ 6.(s-del)(s-sig)*sqr(t-u)/u/s/s/s/sqr(sqr(beta))
	)*log(-t/mW2);

	Val += ( -2.(2.tt(2.sig-3.s)+6.sigt(s-sig)+sqr(s-sig)(s+2.*sig))
	/u/s/sqr(beta)
	+3.s(4.t-4.sig-s)/u
	-3.sqr(s-sig)sqr(t-u)/u/s/s/sqr(sqr(beta))
	)*TildeI3WZ(s,mW2,mZ2,beta);

	Val += ( 4.(u+4.s)/3./u - 4.(ut+2.ssig)/3./mW2/mZ2
	)pipi;

	Val += -( 16.s(t-sig)*(t-mW2)/t/u
	)*TildeI3W(s,t,mW2);

	Val += ( 8.ss*(t-sig)/u
	)*TildeI4t(s,t,mW2,mZ2);
	swap(t,u);
	swap(mW2,mZ2);
	del *= -1;

	return Val;
	}

	/***************************************************************************/
	double Iuu1(Energy2 s, Energy2 t, Energy2 u, Energy2 mW2, Energy2 mZ2, double beta) {
	double Val(Idd1(s,u,t,mW2,mZ2,beta));
	return Val;
	}

	/***************************************************************************/
	Energy2 Fd1 (Energy2 s, Energy2 t, Energy2 u, Energy2 mW2, Energy2 mZ2, double beta) {
	Energy2 sig(mZ2+mW2);
	Energy2 del(mZ2-mW2);
	Energy2 Val(0.*GeV2);

	Val += 4.(17.tt+t(11.s-13.sig)+17.(ssig+mW2*mZ2))/t
	+ 16.(s-sig)(tu+2.s*sig)/mW2/mZ2
	+ 4ss(2.t-sig)/(t(u+s)-mW2mZ2);

	Val += ( 8.*(t-u)/sqr(beta)
	- 4.(3.tt-t(s+3.sig)+3.(ssig+mW2mZ2))/t
	)*log(-t/s);

	Val += ( 8.(tt-t(2.s+3.mW2+mZ2)+3.(ssig+mW2mZ2))/t
	+ 8.s(t(3.s+2.sig)-2.mZ2(s+sig))/(t(u+s)-mW2*mZ2)
	+ 8.sst(2.t-sig)(t-mZ2)/sqr(t(u+s)-mW2mZ2)
	- 8.(s-del)(t-u)/s/sqr(beta)
	)*log(-t/mW2);

	Val += ( 4.(s-sig)(t-u)/sqr(beta)
	+ 4.(sig-3.s)*t
	+ 4.(4.ssig-mZ2mZ2-mW2*mW2)
	)*TildeI3WZ(s,mW2,mZ2,beta);

	Val += -( 8.(3.tt+2.t(2.s-sig)+2.(ssig+mW2*mZ2))/3./t
	+ 8.(s-sig)(tu+2.s*sig)/3./mW2/mZ2
	)pipi;

	Val += ( 4.(stt-s(s+sig)t+2.s(ssig+mW2*mZ2))
	)*TildeI4t(s,t,mW2,mZ2);

	Val += -( 8.(t-mW2)(tt-t(s+sig)+2.(ssig+mW2*mZ2))/t
	)*TildeI3W(s,t,mW2);


	swap(mW2,mZ2);
	del *= -1;
	Val += 4.(17.tt+t(11.s-13.sig)+17.(ssig+mW2*mZ2))/t
	+ 16.(s-sig)(tu+2.s*sig)/mW2/mZ2
	+ 4ss(2.t-sig)/(t(u+s)-mW2mZ2);

	Val += ( 8.*(t-u)/sqr(beta)
	- 4.(3.tt-t(s+3.sig)+3.(ssig+mW2mZ2))/t
	)*log(-t/s);

	Val += ( 8.(tt-t(2.s+3.mW2+mZ2)+3.(ssig+mW2mZ2))/t
	+ 8.s(t(3.s+2.sig)-2.mZ2(s+sig))/(t(u+s)-mW2*mZ2)
	+ 8.sst(2.t-sig)(t-mZ2)/sqr(t(u+s)-mW2mZ2)
	- 8.(s-del)(t-u)/s/sqr(beta)
	)*log(-t/mW2);

	Val += ( 4.(s-sig)(t-u)/sqr(beta)
	+ 4.(sig-3.s)*t
	+ 4.(4.ssig-mZ2mZ2-mW2*mW2)
	)*TildeI3WZ(s,mW2,mZ2,beta);

	Val += -( 8.(3.tt+2.t(2.s-sig)+2.(ssig+mW2*mZ2))/3./t
	+ 8.(s-sig)(tu+2.s*sig)/3./mW2/mZ2
	)pipi;

	Val += ( 4.(stt-s(s+sig)t+2.s(ssig+mW2*mZ2))
	)*TildeI4t(s,t,mW2,mZ2);

	Val += -( 8.(t-mW2)(tt-t(s+sig)+2.(ssig+mW2*mZ2))/t
	)*TildeI3W(s,t,mW2);
	swap(mW2,mZ2);
	del *= -1;

	return Val;
	}

	/***************************************************************************/
	Energy2 Fu1 (Energy2 s, Energy2 t, Energy2 u, Energy2 mW2, Energy2 mZ2, double beta) {
	Energy2 Val(Fd1(s,u,t,mW2,mZ2,beta));
	return Val;
	}

	/***************************************************************************/
	Energy4 H1 (Energy2 s, Energy2 t, Energy2 u, Energy2 mW2, Energy2 mZ2) {
	Energy2 sig(mZ2+mW2);
	Energy4 Val(0.GeV2GeV2);
	Val = 8.tt+8.t(s-sig)+ss+6.ssig+mZ2mZ2+10.mW2mZ2+mW2*mW2
	- sqr(s-sig)(tu+2.ssig)/mW2/mZ2;
	Val = ( 16.-8.pi*pi/3.);
	return Val;
	}

	Energy2 t_u_Rdd(Energy2 s , Energy2 tk , Energy2 uk , Energy2 q1 , Energy2 q2,
	Energy2 mW2, Energy2 mZ2);
	Energy2 t_u_Rud(Energy2 s , Energy2 tk , Energy2 uk , Energy2 q1 , Energy2 q2,
	Energy2 q1h, Energy2 q2h, Energy2 mW2, Energy2 mZ2);
	Energy2 t_u_Ruu(Energy2 s , Energy2 tk , Energy2 uk, Energy2 q1h, Energy2 q2h,
	Energy2 mW2, Energy2 mZ2);
	Energy4 t_u_RZds(Energy2 s ,Energy2 tk , Energy2 uk , Energy2 q1, Energy2 q2,
	Energy2 s2,Energy2 mW2, Energy2 mZ2);
	Energy4 t_u_RZda(Energy2 s , Energy2 tk , Energy2 uk , Energy2 q1, Energy2 q2,
	Energy2 s2, Energy2 mW2, Energy2 mZ2);
	Energy4 t_u_RZd(Energy2 s , Energy2 tk , Energy2 uk , Energy2 q1 , Energy2 q2 ,
	Energy2 s2 , Energy2 mW2, Energy2 mZ2);
	Energy4 t_u_RZu(Energy2 s , Energy2 tk , Energy2 uk , Energy2 q1h, Energy2 q2h,
	Energy2 s2 , Energy2 mW2, Energy2 mZ2);
	Energy6 t_u_RZs(Energy2 s , Energy2 tk , Energy2 uk , Energy2 q1, Energy2 q2,
	Energy2 s2, Energy2 mW2, Energy2 mZ2);
	Energy6 t_u_RZa(Energy2 s , Energy2 tk , Energy2 uk , Energy2 q1, Energy2 q2,
	Energy2 s2, Energy2 mW2, Energy2 mZ2);
	Energy6 t_u_RZ(Energy2 s , Energy2 tk , Energy2 uk , Energy2 q1, Energy2 q2,
	Energy2 s2 , Energy2 mW2, Energy2 mZ2);

	/***************************************************************************/
	// t_u_M_R_qqb is the real emission q + qb -> n + g matrix element
	// exactly as defined in Eqs. C.1 of NPB 383(1992)3-44, multiplied by
	// tk * uk!
	Energy2 MEPP2VVPowheg::t_u_M_R_qqb(realVVKinematics R) const {
	// First the Born variables:
	Energy2 s2(R.s2r());
	Energy2 mW2(R.k12r());
	Energy2 mZ2(R.k22r());
	// Then the rest:
	Energy2 s(R.sr());
	Energy2 tk(R.tkr());
	Energy2 uk(R.ukr());
	Energy2 q1(R.q1r());
	Energy2 q2(R.q2r());
	Energy2 q1h(R.q1hatr());
	Energy2 q2h(R.q2hatr());

	double cosThetaW(sqrt(1.-sin2ThetaW_));
	double eZ2(eZ2_);
	double eZ(eZ_);
	double gdL(gdL_);
	double guL(guL_);
	double gdR(gdR_);
	double guR(guR_);

	// W+W-
	if(abs(mePartonData()[2]->id())==24&&abs(mePartonData()[3]->id())==24) {
	double e2(sqr(gW_)*sin2ThetaW_);
	if(abs(quark_->id())%2==0&&abs(antiquark_->id())%2==0) {
	// N.B. OLD eZ used to calculate new eZ2 then new eZ is set!
	if(quark_->id()==-antiquark_->id()) {
	eZ2 = 1./2.*sqr(s2-mW2)/Fij2_
	* (e2e2/s2/s2(sqr( 2./3.+eZ(guL+guR)/2./e2s2/(s2-mW2/sqr(cosThetaW)))
	+sqr( eZ(guL-guR)/2./e2s2/(s2-mW2/sqr(cosThetaW))))
	);
	eZ = -1./2./Fij2_/(gW_gW_/4./sqrt(Fij2_))(s2-mW2)
	* (gW_gW_e2/4./s2 ( 2./3.+2.eZguL/2./e2s2/(s2-mW2/sqr(cosThetaW))));
	} else {
	eZ2 =0.;
	eZ =0.;
	}
	gdL = gW_/sqrt(2.);
	guL = 0.;
	}
	else if(abs(quark_->id())%2==1&&abs(antiquark_->id())%2==1) {
	// N.B. OLD eZ used to calculate new eZ2 then new eZ is set!
	if(quark_->id()==-antiquark_->id()) {
	eZ2 = 1./2.*sqr(s2-mW2)/Fij2_
	* (e2e2/s2/s2(sqr(-1./3.+eZ(gdL+gdR)/2./e2s2/(s2-mW2/sqr(cosThetaW)))
	+sqr( eZ(gdL-gdR)/2./e2s2/(s2-mW2/sqr(cosThetaW))))
	);
	eZ = -1./2./Fij2_/(gW_gW_/4./sqrt(Fij2_))(s2-mW2)
	* (gW_gW_e2/4./s2 (-1./3.+2.eZgdL/2./e2s2/(s2-mW2/sqr(cosThetaW))));
	} else {
	eZ2 =0.;
	eZ =0.;
	}
	guL = gW_/sqrt(2.);
	gdL = 0.;
	}
	}
	// ZZ
	else if(mePartonData()[2]->id()==23&&mePartonData()[3]->id()==23) {
	eZ = 0.;
	eZ2 = 0.;
	double gV2,gA2;
	gV2 = sqr(guL/2.-gW_/2./cosThetaW2./3.sin2ThetaW_);
	gA2 = sqr(guL/2.+gW_/2./cosThetaW2./3.sin2ThetaW_);
	guL = sqrt(gV2gV2+gA2gA2+6.gA2gV2)/2.;
	gV2 = sqr(gdL/2.+gW_/2./cosThetaW1./3.sin2ThetaW_);
	gA2 = sqr(gdL/2.-gW_/2./cosThetaW1./3.sin2ThetaW_);
	gdL = sqrt(gV2gV2+gA2gA2+6.gA2gV2)/2.;
	if(abs(quark_->id())%2==0&&abs(antiquark_->id())%2==0) gdL = guL;
	else if(abs(quark_->id())%2==1&&abs(antiquark_->id())%2==1) guL = gdL;
	else {
	cout << "MEPP2VVPowheg:" << endl;
	cout << "ZZ needs 2 down-type / 2 up-type!" << endl;
	}
	}

	return -2.pialphaS_Fij2_CF_/NC_
	* ( gdLgdLt_u_Rdd(s,tk,uk,q1,q2,mW2,mZ2)
	+ 2.gdLguL*t_u_Rud(s,tk,uk,q1,q2,q1h,q2h,mW2,mZ2)
	+ guLguLt_u_Ruu(s,tk,uk,q1h,q2h,mW2,mZ2)
	- 2.eZ/(s2-mW2) ( gdL
	* t_u_RZd(s,tk,uk,q1 ,q2 ,s2,mW2,mZ2)
	- guL
	* t_u_RZu(s,tk,uk,q1h,q2h,s2,mW2,mZ2)
	)
	+ eZ2/sqr(s2-mW2) *t_u_RZ(s,tk,uk,q1,q2,s2,mW2,mZ2)
	);
	}

	Energy2 t_u_Rdd(Energy2 s ,Energy2 tk ,Energy2 uk ,Energy2 q1,Energy2 q2,
	Energy2 mW2, Energy2 mZ2) {
	Energy2 Val(0.*GeV2);

	Val += 4.(q2(uk+2.s+q2)+q1(s+q1))/mW2/mZ2*uk
	+ 16.(uk+s)/q2uk
	- 4.(2.uk+4.s+q2)/mW2uk
	- 4.(2.uk+5.s+q2+2.q1-mW2)/mZ2*uk
	+ 4.q1s*(s+q1)/mW2/mZ2
	+ 16.s(s+q2-mZ2-mW2)/q1
	- 4.s(4.*s+q2+q1)/mW2
	+ 16.mW2mZ2*s/q1/q2
	+ 4.*s
	+ 16.mZ2(tk-2.mW2)/q1/q2/q2tk*uk
	+ 16.(2.mZ2+mW2-tk)/q1/q2tkuk
	+ 16.mW2(s-mZ2-mW2)/q1/q2*uk
	+ 16.mZ2(q1-2.mW2)/q2/q2uk
	+ 32.mW2mW2mZ2/q1/q2/q2uk
	+ 16.mW2/q1uk
	+ 4.*uk
	+ 8./q2tkuk
	+ 4.q1/mW2/mZ2tk*uk
	- 24./q1tkuk
	- 4./mW2tkuk;

	swap(mW2,mZ2);
	swap(q1,q2);
	swap(tk,uk);
	Val += 4.(q2(uk+2.s+q2)+q1(s+q1))/mW2/mZ2*uk
	+ 16.(uk+s)/q2uk
	- 4.(2.uk+4.s+q2)/mW2uk
	- 4.(2.uk+5.s+q2+2.q1-mW2)/mZ2*uk
	+ 4.q1s*(s+q1)/mW2/mZ2
	+ 16.s(s+q2-mZ2-mW2)/q1
	- 4.s(4.*s+q2+q1)/mW2
	+ 16.mW2mZ2*s/q1/q2
	+ 4.*s
	+ 16.mZ2(tk-2.mW2)/q1/q2/q2tk*uk
	+ 16.(2.mZ2+mW2-tk)/q1/q2tkuk
	+ 16.mW2(s-mZ2-mW2)/q1/q2*uk
	+ 16.mZ2(q1-2.mW2)/q2/q2uk
	+ 32.mW2mW2mZ2/q1/q2/q2uk
	+ 16.mW2/q1uk
	+ 4.*uk
	+ 8./q2tkuk
	+ 4.q1/mW2/mZ2tk*uk
	- 24./q1tkuk
	- 4./mW2tkuk;
	swap(mW2,mZ2);
	swap(q1,q2);
	swap(tk,uk);

	return Val;
	}
	Energy2 t_u_Rud(Energy2 s ,Energy2 tk ,Energy2 uk ,Energy2 q1,Energy2 q2,
	Energy2 q1h,Energy2 q2h,Energy2 mW2, Energy2 mZ2) {
	Energy2 Val(0.*GeV2);

	Val += (uks(uk+3.s+q1h)+ss(s+mZ2)-(s+uk)(2.mZ2s+3.mW2s+mW2*q1h)
	) * 8./q1/q2h/q2*uk
	- (uk(uk+3.s+q1h-mW2)-(q2+s)(q2-s)+s(q2-mW2)+q1h(q2-mW2)+mW2q2
	) * 4.s/mZ2/q1/q2huk
	- 4.((s+uk+q2h-2.mZ2)(s+q1h-mZ2)-mZ2q1)/mW2/q2*uk
	+ 4.(2.suk+2.mW2uk+5.ss+2.q1hs-2.mZ2s)/q1/q2huk
	+ 4.(2.suk-ss-2.q1hs+2.mW2s+2.mW2q1h)/q1/q2h/q2tkuk
	+ ((2.uk+s)(s+q1h)+s(q2+q2h)+2.q2(s+q2h)-q1s+q1q2+q1hq2h
	) /mW2/mZ2*uk
	+ 8.s(uk-q1h+mZ2)/q1/q2*uk
	+ 4.s(-uk+s-q2+q1+q1h)/mZ2/q2h*uk
	+ 4.s(-uk-q2+q1h)/mZ2/q1*uk
	+ 8.(mZ2uk-ss+mW2s-2.mZ2q1-2.mZ2q1h)/q2h/q2*uk
	+ 2.(-uk-9.s-4.q2-5.q2h-3.q1-4.q1h+8.mZ2)/mW2uk
	+ 2.(-4.uk+3.s+5.q1+4.q1h)/q2huk
	+ 2.(stk+q2tk+ss-q2q2+q1hq2)/mW2/mZ2*tk
	- 8.s(tk+s+q1h)/mW2/q2*tk
	+ 2.(-tk+3.s+q2-q1h)/mW2*tk
	- 8.ss*s/q1h/q2
	- 2.sq2*(s+q2)/mW2/mZ2
	+ 2.s(2.*s+q2)/mZ2
	+ 2.s(2.*s+q2)/mW2
	- 16.ss/q1h
	- 2.*s
	- 16.ss/q1h/q2*tk
	- 8.s/q2tk
	- 16.s/q1htk
	+ 6.s/mZ2tk
	+ 4.s/q1uk
	+ 4.s/mZ2uk
	+ 12.*uk
	+ 4.s(tk+q1h-mW2)/mZ2/q1/q2htkuk
	+ 2.(s+4.q1+5.q1h-4.mZ2)/q2*uk
	- 4.sss/q1h/q1/q2h/q2tk*uk
	- 4.ss/q1h/q2h/q2tkuk
	- 4.ss/q1h/q1/q2tkuk
	+ 8.ss/mW2/q1h/q2tkuk
	- 4.ss/q1h/q1/q2htkuk
	+ 4.(s+mZ2)/mW2/q2tk*uk
	- 4.s/q1h/q2htk*uk
	- 4.s/q1h/q1tk*uk
	+ 12.s/mW2/q1htk*uk
	- (s+4.q2)/mW2/mZ2tk*uk
	- 4.(s+2.mZ2)/q2h/q2tkuk
	- 4.(3.s+2.q1h)/q1/q2tk*uk
	- 8.mW2/q1/q2htk*uk
	+ 8./q2htkuk
	+ 8./q1tkuk;

	swap(mW2,mZ2);
	swap(q1,q2);
	swap(tk,uk);
	swap(q1h,q2h); // Note this swap is done in accordance with MC@NLO.
	// It is not in NPB 383(1992)3-44 Eq.C.4!
	Val += (uks(uk+3.s+q1h)+ss(s+mZ2)-(s+uk)(2.mZ2s+3.mW2s+mW2*q1h)
	) * 8./q1/q2h/q2*uk
	- (uk(uk+3.s+q1h-mW2)-(q2+s)(q2-s)+s(q2-mW2)+q1h(q2-mW2)+mW2q2
	) * 4.s/mZ2/q1/q2huk
	- 4.((s+uk+q2h-2.mZ2)(s+q1h-mZ2)-mZ2q1)/mW2/q2*uk
	+ 4.(2.suk+2.mW2uk+5.ss+2.q1hs-2.mZ2s)/q1/q2huk
	+ 4.(2.suk-ss-2.q1hs+2.mW2s+2.mW2q1h)/q1/q2h/q2tkuk
	+ ((2.uk+s)(s+q1h)+s(q2+q2h)+2.q2(s+q2h)-q1s+q1q2+q1hq2h
	) /mW2/mZ2*uk
	+ 8.s(uk-q1h+mZ2)/q1/q2*uk
	+ 4.s(-uk+s-q2+q1+q1h)/mZ2/q2h*uk
	+ 4.s(-uk-q2+q1h)/mZ2/q1*uk
	+ 8.(mZ2uk-ss+mW2s-2.mZ2q1-2.mZ2q1h)/q2h/q2*uk
	+ 2.(-uk-9.s-4.q2-5.q2h-3.q1-4.q1h+8.mZ2)/mW2uk
	+ 2.(-4.uk+3.s+5.q1+4.q1h)/q2huk
	+ 2.(stk+q2tk+ss-q2q2+q1hq2)/mW2/mZ2*tk
	- 8.s(tk+s+q1h)/mW2/q2*tk
	+ 2.(-tk+3.s+q2-q1h)/mW2*tk
	- 8.ss*s/q1h/q2
	- 2.sq2*(s+q2)/mW2/mZ2
	+ 2.s(2.*s+q2)/mZ2
	+ 2.s(2.*s+q2)/mW2
	- 16.ss/q1h
	- 2.*s
	- 16.ss/q1h/q2*tk
	- 8.s/q2tk
	- 16.s/q1htk
	+ 6.s/mZ2tk
	+ 4.s/q1uk
	+ 4.s/mZ2uk
	+ 12.*uk
	+ 4.s(tk+q1h-mW2)/mZ2/q1/q2htkuk
	+ 2.(s+4.q1+5.q1h-4.mZ2)/q2*uk
	- 4.sss/q1h/q1/q2h/q2tk*uk
	- 4.ss/q1h/q2h/q2tkuk
	- 4.ss/q1h/q1/q2tkuk
	+ 8.ss/mW2/q1h/q2tkuk
	- 4.ss/q1h/q1/q2htkuk
	+ 4.(s+mZ2)/mW2/q2tk*uk
	- 4.s/q1h/q2htk*uk
	- 4.s/q1h/q1tk*uk
	+ 12.s/mW2/q1htk*uk
	- (s+4.q2)/mW2/mZ2tk*uk
	- 4.(s+2.mZ2)/q2h/q2tkuk
	- 4.(3.s+2.q1h)/q1/q2tk*uk
	- 8.mW2/q1/q2htk*uk
	+ 8./q2htkuk
	+ 8./q1tkuk;
	swap(mW2,mZ2);
	swap(q1,q2);
	swap(tk,uk);
	swap(q1h,q2h); // Note this swap is done in accordance with MC@NLO.
	// It is not in NPB 383(1992)3-44 Eq.C.4!

	swap(tk,uk);
	swap(q1,q2h);
	swap(q2,q1h);
	Val += (uks(uk+3.s+q1h)+ss(s+mZ2)-(s+uk)(2.mZ2s+3.mW2s+mW2*q1h)
	) * 8./q1/q2h/q2*uk
	- (uk(uk+3.s+q1h-mW2)-(q2+s)(q2-s)+s(q2-mW2)+q1h(q2-mW2)+mW2q2
	) * 4.s/mZ2/q1/q2huk
	- 4.((s+uk+q2h-2.mZ2)(s+q1h-mZ2)-mZ2q1)/mW2/q2*uk
	+ 4.(2.suk+2.mW2uk+5.ss+2.q1hs-2.mZ2s)/q1/q2huk
	+ 4.(2.suk-ss-2.q1hs+2.mW2s+2.mW2q1h)/q1/q2h/q2tkuk
	+ ((2.uk+s)(s+q1h)+s(q2+q2h)+2.q2(s+q2h)-q1s+q1q2+q1hq2h
	) /mW2/mZ2*uk
	+ 8.s(uk-q1h+mZ2)/q1/q2*uk
	+ 4.s(-uk+s-q2+q1+q1h)/mZ2/q2h*uk
	+ 4.s(-uk-q2+q1h)/mZ2/q1*uk
	+ 8.(mZ2uk-ss+mW2s-2.mZ2q1-2.mZ2q1h)/q2h/q2*uk
	+ 2.(-uk-9.s-4.q2-5.q2h-3.q1-4.q1h+8.mZ2)/mW2uk
	+ 2.(-4.uk+3.s+5.q1+4.q1h)/q2huk
	+ 2.(stk+q2tk+ss-q2q2+q1hq2)/mW2/mZ2*tk
	- 8.s(tk+s+q1h)/mW2/q2*tk
	+ 2.(-tk+3.s+q2-q1h)/mW2*tk
	- 8.ss*s/q1h/q2
	- 2.sq2*(s+q2)/mW2/mZ2
	+ 2.s(2.*s+q2)/mZ2
	+ 2.s(2.*s+q2)/mW2
	- 16.ss/q1h
	- 2.*s
	- 16.ss/q1h/q2*tk
	- 8.s/q2tk
	- 16.s/q1htk
	+ 6.s/mZ2tk
	+ 4.s/q1uk
	+ 4.s/mZ2uk
	+ 12.*uk
	+ 4.s(tk+q1h-mW2)/mZ2/q1/q2htkuk
	+ 2.(s+4.q1+5.q1h-4.mZ2)/q2*uk
	- 4.sss/q1h/q1/q2h/q2tk*uk
	- 4.ss/q1h/q2h/q2tkuk
	- 4.ss/q1h/q1/q2tkuk
	+ 8.ss/mW2/q1h/q2tkuk
	- 4.ss/q1h/q1/q2htkuk
	+ 4.(s+mZ2)/mW2/q2tk*uk
	- 4.s/q1h/q2htk*uk
	- 4.s/q1h/q1tk*uk
	+ 12.s/mW2/q1htk*uk
	- (s+4.q2)/mW2/mZ2tk*uk
	- 4.(s+2.mZ2)/q2h/q2tkuk
	- 4.(3.s+2.q1h)/q1/q2tk*uk
	- 8.mW2/q1/q2htk*uk
	+ 8./q2htkuk
	+ 8./q1tkuk;
	swap(tk,uk);
	swap(q1,q2h);
	swap(q2,q1h);

	swap(mW2,mZ2);
	swap(q1,q1h);
	swap(q2,q2h);
	Val += (uks(uk+3.s+q1h)+ss(s+mZ2)-(s+uk)(2.mZ2s+3.mW2s+mW2*q1h)
	) * 8./q1/q2h/q2*uk
	- (uk(uk+3.s+q1h-mW2)-(q2+s)(q2-s)+s(q2-mW2)+q1h(q2-mW2)+mW2q2
	) * 4.s/mZ2/q1/q2huk
	- 4.((s+uk+q2h-2.mZ2)(s+q1h-mZ2)-mZ2q1)/mW2/q2*uk
	+ 4.(2.suk+2.mW2uk+5.ss+2.q1hs-2.mZ2s)/q1/q2huk
	+ 4.(2.suk-ss-2.q1hs+2.mW2s+2.mW2q1h)/q1/q2h/q2tkuk
	+ ((2.uk+s)(s+q1h)+s(q2+q2h)+2.q2(s+q2h)-q1s+q1q2+q1hq2h
	) /mW2/mZ2*uk
	+ 8.s(uk-q1h+mZ2)/q1/q2*uk
	+ 4.s(-uk+s-q2+q1+q1h)/mZ2/q2h*uk
	+ 4.s(-uk-q2+q1h)/mZ2/q1*uk
	+ 8.(mZ2uk-ss+mW2s-2.mZ2q1-2.mZ2q1h)/q2h/q2*uk
	+ 2.(-uk-9.s-4.q2-5.q2h-3.q1-4.q1h+8.mZ2)/mW2uk
	+ 2.(-4.uk+3.s+5.q1+4.q1h)/q2huk
	+ 2.(stk+q2tk+ss-q2q2+q1hq2)/mW2/mZ2*tk
	- 8.s(tk+s+q1h)/mW2/q2*tk
	+ 2.(-tk+3.s+q2-q1h)/mW2*tk
	- 8.ss*s/q1h/q2
	- 2.sq2*(s+q2)/mW2/mZ2
	+ 2.s(2.*s+q2)/mZ2
	+ 2.s(2.*s+q2)/mW2
	- 16.ss/q1h
	- 2.*s
	- 16.ss/q1h/q2*tk
	- 8.s/q2tk
	- 16.s/q1htk
	+ 6.s/mZ2tk
	+ 4.s/q1uk
	+ 4.s/mZ2uk
	+ 12.*uk
	+ 4.s(tk+q1h-mW2)/mZ2/q1/q2htkuk
	+ 2.(s+4.q1+5.q1h-4.mZ2)/q2*uk
	- 4.sss/q1h/q1/q2h/q2tk*uk
	- 4.ss/q1h/q2h/q2tkuk
	- 4.ss/q1h/q1/q2tkuk
	+ 8.ss/mW2/q1h/q2tkuk
	- 4.ss/q1h/q1/q2htkuk
	+ 4.(s+mZ2)/mW2/q2tk*uk
	- 4.s/q1h/q2htk*uk
	- 4.s/q1h/q1tk*uk
	+ 12.s/mW2/q1htk*uk
	- (s+4.q2)/mW2/mZ2tk*uk
	- 4.(s+2.mZ2)/q2h/q2tkuk
	- 4.(3.s+2.q1h)/q1/q2tk*uk
	- 8.mW2/q1/q2htk*uk
	+ 8./q2htkuk
	+ 8./q1tkuk;
	swap(mW2,mZ2);
	swap(q1,q1h);
	swap(q2,q2h);

	return Val;
	}

	Energy2 t_u_Ruu(Energy2 s ,Energy2 tk ,Energy2 uk ,Energy2 q1h,Energy2 q2h,
	Energy2 mW2, Energy2 mZ2) {
	return t_u_Rdd(s,tk,uk,q1h,q2h,mZ2,mW2);
	}

	Energy4 t_u_RZds(Energy2 s ,Energy2 tk ,Energy2 uk ,Energy2 q1,Energy2 q2,
	Energy2 s2, Energy2 mW2, Energy2 mZ2) {
	Energy4 Val(0.GeV2GeV2);
	Energy2 sig(mZ2+mW2);

	Val += ( q1q2(5./2.ss+5.stk+3.tktk)+(tkukuk+q1q1q2)*(tk+s)
	+ q1(tktkuk+sukuk-sstk+ssuk)+q1q1q1(uk+s)-q1q1s*s2
	) * 8./q1/q2
	- ( tktk(4.uk+s+q1-2.q2)+tk(sqr(q1+q2)-q1s-3.q2s-2.q1q1)
	- q1s(4.s-2.q1-q2)+tkuk(q1+3.*s)
	) * 4.*sig/q1/q2
	- 4.sigsig(s(2.s+q1)+tk(uk+5./2.tk+5.s+q1+q2)
	)/mW2/mZ2
	+ 2.sigs2(4.sqr(s+tk)+tk(uk+s+4.q1+2.q2)+2.q1(2.s+q1)
	)/mW2/mZ2
	+ 4.sigsig(s2+s-q1+q2)/q1/q2tk
	- 16.mW2mZ2(tkuk/2.+q2tk-q1s)/q1/q2
	- 4.s2s2q1(tk+s+q1)/mW2/mZ2
	+ sigsigsig*(uk+tk)/mW2/mZ2
	+ 4.mW2mZ2sig(uk+tk)/q1/q2;

	swap(mW2,mZ2);
	swap(q1,q2);
	swap(tk,uk);
	Val += ( q1q2(5./2.ss+5.stk+3.tktk)+(tkukuk+q1q1q2)*(tk+s)
	+ q1(tktkuk+sukuk-sstk+ssuk)+q1q1q1(uk+s)-q1q1s*s2
	) * 8./q1/q2
	- ( tktk(4.uk+s+q1-2.q2)+tk(sqr(q1+q2)-q1s-3.q2s-2.q1q1)
	- q1s(4.s-2.q1-q2)+tkuk(q1+3.*s)
	) * 4.*sig/q1/q2
	- 4.sigsig(s(2.s+q1)+tk(uk+5./2.tk+5.s+q1+q2)
	)/mW2/mZ2
	+ 2.sigs2(4.sqr(s+tk)+tk(uk+s+4.q1+2.q2)+2.q1(2.s+q1)
	)/mW2/mZ2
	+ 4.sigsig(s2+s-q1+q2)/q1/q2tk
	- 16.mW2mZ2(tkuk/2.+q2tk-q1s)/q1/q2
	- 4.s2s2q1(tk+s+q1)/mW2/mZ2
	+ sigsigsig*(uk+tk)/mW2/mZ2
	+ 4.mW2mZ2sig(uk+tk)/q1/q2;
	swap(mW2,mZ2);
	swap(q1,q2);
	swap(tk,uk);

	return Val;
	}
	Energy4 t_u_RZda(Energy2 s ,Energy2 tk ,Energy2 uk ,Energy2 q1,Energy2 q2,
	Energy2 s2, Energy2 mW2, Energy2 mZ2) {
	Energy4 Val(0.GeV2GeV2);

	Val += 4.mZ2(2.ukuk-stk+q1(uk-tk-s+q1+0.5q2)+q2(s-3.*q2)
	) /q1/q2*tk
	- 4.mZ2mZ2(q1-tk-2.s-q2)/q1/q2*tk
	- 2.mZ2(tk+2.s+2.q2)/mW2*tk
	- 2.s2(s+2.q2)/mZ2tk
	+ 8.mW2mZ2mZ2/q1/q2tk
	+ 2.mZ2mZ2/mW2*tk;

	swap(mW2,mZ2); // N.B. Here we subtract!
	Val -= 4.mZ2(2.ukuk-stk+q1(uk-tk-s+q1+0.5q2)+q2(s-3.*q2)
	) /q1/q2*tk
	- 4.mZ2mZ2(q1-tk-2.s-q2)/q1/q2*tk
	- 2.mZ2(tk+2.s+2.q2)/mW2*tk
	- 2.s2(s+2.q2)/mZ2tk
	+ 8.mW2mZ2mZ2/q1/q2tk
	+ 2.mZ2mZ2/mW2*tk;
	swap(mW2,mZ2);

	swap(q1,q2); // N.B. Here we subtract!
	swap(tk,uk);
	Val -= 4.mZ2(2.ukuk-stk+q1(uk-tk-s+q1+0.5q2)+q2(s-3.*q2)
	) /q1/q2*tk
	- 4.mZ2mZ2(q1-tk-2.s-q2)/q1/q2*tk
	- 2.mZ2(tk+2.s+2.q2)/mW2*tk
	- 2.s2(s+2.q2)/mZ2tk
	+ 8.mW2mZ2mZ2/q1/q2tk
	+ 2.mZ2mZ2/mW2*tk;
	swap(q1,q2);
	swap(tk,uk);

	swap(mW2,mZ2); // N.B. Here we add!
	swap(q1,q2);
	swap(tk,uk);
	Val += 4.mZ2(2.ukuk-stk+q1(uk-tk-s+q1+0.5q2)+q2(s-3.*q2)
	) /q1/q2*tk
	- 4.mZ2mZ2(q1-tk-2.s-q2)/q1/q2*tk
	- 2.mZ2(tk+2.s+2.q2)/mW2*tk
	- 2.s2(s+2.q2)/mZ2tk
	+ 8.mW2mZ2mZ2/q1/q2tk
	+ 2.mZ2mZ2/mW2*tk;
	swap(mW2,mZ2);
	swap(q1,q2);
	swap(tk,uk);

	return Val;
	}
	Energy4 t_u_RZd(Energy2 s , Energy2 tk , Energy2 uk , Energy2 q1 , Energy2 q2 ,
	Energy2 s2, Energy2 mW2, Energy2 mZ2) {
	Energy4 Val(0.GeV2GeV2);

	Val = t_u_RZds(s,tk,uk,q1,q2,s2,mW2,mZ2)
	+ t_u_RZda(s,tk,uk,q1,q2,s2,mW2,mZ2);

	return Val;
	}
	Energy4 t_u_RZu(Energy2 s , Energy2 tk , Energy2 uk , Energy2 q1h, Energy2 q2h,
	Energy2 s2, Energy2 mW2, Energy2 mZ2) {
	Energy4 Val(0.GeV2GeV2);

	Val = t_u_RZd(s,tk,uk,q1h,q2h,s2,mZ2,mW2);

	return Val;
	}
	Energy6 t_u_RZs(Energy2 s,Energy2 tk,Energy2 uk,Energy2 q1,Energy2 q2,
	Energy2 s2,Energy2 mW2,Energy2 mZ2) {
	Energy6 Val(0.GeV2GeV2*GeV2);
	Energy2 sig(mZ2+mW2);

	Val += 2.sigsigs2( tk(3.uk+9.tk+19.s+6.q1+4.q2)+8.ss+6.q1s
	+ 2.q1q1
	)/mW2/mZ2
	- 2.sigsigsig(tk(3.uk+6.tk+11.s+2.q1+2.q2)+2.s(2.*s+q1))
	/ mW2/mZ2
	- 2.sigs2s2(tk(uk+4.tk+9.s+6.q1+2.q2)+4.sqr(s+q1)-2.q1s)
	/mW2/mZ2
	- 16.sig(2.tk(uk/2.-tk-s+q1+q2)-s(3.s/2.-2.*q1))
	+ 8.s2(s(s/2.+tk)+4.q1*(tk+s+q1))
	+ 4.s2s2s2q1*(tk+s+q1)/mW2/mZ2
	+ 8.sigsig(2.tk+s/2.)
	+ 2.sigsigsigsig*tk/mW2/mZ2
	+ 32.mW2mZ2*s;

	swap(mW2,mZ2);
	swap(q1,q2);
	swap(tk,uk);
	Val += 2.sigsigs2( tk(3.uk+9.tk+19.s+6.q1+4.q2)+8.ss+6.q1s
	+ 2.q1q1
	)/mW2/mZ2
	- 2.sigsigsig(tk(3.uk+6.tk+11.s+2.q1+2.q2)+2.s(2.*s+q1))
	/ mW2/mZ2
	- 2.sigs2s2(tk(uk+4.tk+9.s+6.q1+2.q2)+4.sqr(s+q1)-2.q1s)
	/mW2/mZ2
	- 16.sig(2.tk(uk/2.-tk-s+q1+q2)-s(3.s/2.-2.*q1))
	+ 8.s2(s(s/2.+tk)+4.q1*(tk+s+q1))
	+ 4.s2s2s2q1*(tk+s+q1)/mW2/mZ2
	+ 8.sigsig(2.tk+s/2.)
	+ 2.sigsigsigsig*tk/mW2/mZ2
	+ 32.mW2mZ2*s;
	swap(mW2,mZ2);
	swap(q1,q2);
	swap(tk,uk);

	return Val;
	}
	Energy6 t_u_RZa(Energy2 s,Energy2 tk,Energy2 uk,Energy2 q1,Energy2 q2,
	Energy2 s2,Energy2 mW2,Energy2 mZ2) {
	Energy6 Val(0.GeV2GeV2*GeV2);

	Val += - 2.mZ2(2.tk+11.s+18.q2)tk
	- 2.mZ2mZ2(2.tk+3.s+2.q2)/mW2*tk
	+ 2.mZ2s2(tk+3.s+4.q2)/mW2tk
	- 2.s2s2(s+2.q2)/mW2*tk
	+ 2.mZ2mZ2mZ2/mW2tk
	+ 20.mZ2mZ2*tk;

	swap(mW2,mZ2);
	Val -= - 2.mZ2(2.tk+11.s+18.q2)tk
	- 2.mZ2mZ2(2.tk+3.s+2.q2)/mW2*tk
	+ 2.mZ2s2(tk+3.s+4.q2)/mW2tk
	- 2.s2s2(s+2.q2)/mW2*tk
	+ 2.mZ2mZ2mZ2/mW2tk
	+ 20.mZ2mZ2*tk;
	swap(mW2,mZ2);

	swap(q1,q2);
	swap(tk,uk);
	Val -= - 2.mZ2(2.tk+11.s+18.q2)tk
	- 2.mZ2mZ2(2.tk+3.s+2.q2)/mW2*tk
	+ 2.mZ2s2(tk+3.s+4.q2)/mW2tk
	- 2.s2s2(s+2.q2)/mW2*tk
	+ 2.mZ2mZ2mZ2/mW2tk
	+ 20.mZ2mZ2*tk;
	swap(q1,q2);
	swap(tk,uk);

	swap(mW2,mZ2);
	swap(q1,q2);
	swap(tk,uk);
	Val += - 2.mZ2(2.tk+11.s+18.q2)tk
	- 2.mZ2mZ2(2.tk+3.s+2.q2)/mW2*tk
	+ 2.mZ2s2(tk+3.s+4.q2)/mW2tk
	- 2.s2s2(s+2.q2)/mW2*tk
	+ 2.mZ2mZ2mZ2/mW2tk
	+ 20.mZ2mZ2*tk;
	swap(mW2,mZ2);
	swap(q1,q2);
	swap(tk,uk);

	return Val;
	}
	Energy6 t_u_RZ(Energy2 s , Energy2 tk , Energy2 uk , Energy2 q1, Energy2 q2,
	Energy2 s2, Energy2 mW2, Energy2 mZ2) {
	Energy6 Val(0.GeV2GeV2*GeV2);

	Val = t_u_RZs(s,tk,uk,q1,q2,s2,mW2,mZ2)
	+ t_u_RZa(s,tk,uk,q1,q2,s2,mW2,mZ2);

	return Val;
	}

	/***************************************************************************/
	// t_u_M_R_qg is the real emission q + qb -> n + g matrix element
	// exactly as defined in Eqs. C.9 of NPB 383(1992)3-44, multiplied by
	// tk * uk!
	Energy2 MEPP2VVPowheg::t_u_M_R_qg(realVVKinematics R) const {
	// First the Born variables:
	Energy2 s2(R.s2r());
	Energy2 mW2(R.k12r());
	Energy2 mZ2(R.k22r());
	// Then the rest:
	Energy2 s(R.sr());
	Energy2 tk(R.tkr());
	Energy2 uk(R.ukr());
	Energy2 q1(R.q1r());
	Energy2 q2(R.q2r());
	Energy2 q1h(R.q1hatr());
	Energy2 q2h(R.q2hatr());
	Energy2 w1(R.w1r());
	Energy2 w2(R.w2r());

	double cosThetaW(sqrt(1.-sin2ThetaW_));
	double eZ2(eZ2_);
	double eZ(eZ_);
	double gdL(gdL_);
	double guL(guL_);
	double gdR(gdR_);
	double guR(guR_);

	// W+W-
	if(abs(mePartonData()[2]->id())==24&&abs(mePartonData()[3]->id())==24) {
	double e2(sqr(gW_)*sin2ThetaW_);
	if(abs(quark_->id())%2==0&&abs(antiquark_->id())%2==0) {
	// N.B. OLD eZ used to calculate new eZ2 then new eZ is set!
	if(quark_->id()==-antiquark_->id()) {
	eZ2 = 1./2.*sqr(s2-mW2)/Fij2_
	* (e2e2/s2/s2(sqr( 2./3.+eZ(guL+guR)/2./e2s2/(s2-mW2/sqr(cosThetaW)))
	+sqr( eZ(guL-guR)/2./e2s2/(s2-mW2/sqr(cosThetaW))))
	);
	eZ = -1./2./Fij2_/(gW_gW_/4./sqrt(Fij2_))(s2-mW2)
	* (gW_gW_e2/4./s2 ( 2./3.+2.eZguL/2./e2s2/(s2-mW2/sqr(cosThetaW))));
	} else {
	eZ2 =0.;
	eZ =0.;
	}
	gdL = gW_/sqrt(2.);
	guL = 0.;
	}
	else if(abs(quark_->id())%2==1&&abs(antiquark_->id())%2==1) {
	// N.B. OLD eZ used to calculate new eZ2 then new eZ is set!
	if(quark_->id()==-antiquark_->id()) {
	eZ2 = 1./2.*sqr(s2-mW2)/Fij2_
	* (e2e2/s2/s2(sqr(-1./3.+eZ(gdL+gdR)/2./e2s2/(s2-mW2/sqr(cosThetaW)))
	+sqr( eZ(gdL-gdR)/2./e2s2/(s2-mW2/sqr(cosThetaW))))
	);
	eZ = -1./2./Fij2_/(gW_gW_/4./sqrt(Fij2_))(s2-mW2)
	* (gW_gW_e2/4./s2 (-1./3.+2.eZgdL/2./e2s2/(s2-mW2/sqr(cosThetaW))));
	} else {
	eZ2 =0.;
	eZ =0.;
	}
	guL = gW_/sqrt(2.);
	gdL = 0.;
	}
	}
	// ZZ
	else if(mePartonData()[2]->id()==23&&mePartonData()[3]->id()==23) {
	eZ = 0.;
	eZ2 = 0.;
	double gV2,gA2;
	gV2 = sqr(guL/2.-gW_/2./cosThetaW2./3.sin2ThetaW_);
	gA2 = sqr(guL/2.+gW_/2./cosThetaW2./3.sin2ThetaW_);
	guL = sqrt(gV2gV2+gA2gA2+6.gA2gV2)/2.;
	gV2 = sqr(gdL/2.+gW_/2./cosThetaW1./3.sin2ThetaW_);
	gA2 = sqr(gdL/2.-gW_/2./cosThetaW1./3.sin2ThetaW_);
	gdL = sqrt(gV2gV2+gA2gA2+6.gA2gV2)/2.;
	if(abs(quark_->id())%2==0&&abs(antiquark_->id())%2==0) gdL = guL;
	else if(abs(quark_->id())%2==1&&abs(antiquark_->id())%2==1) guL = gdL;
	else {
	cout << "MEPP2VVPowheg:" << endl;
	cout << "ZZ needs 2 down-type / 2 up-type!" << endl;
	}
	}

	Energy2 Val(0.*GeV2);

	swap(s,tk);
	swap(q2,w2);
	swap(q2h,w1);
	Val = -2.pialphaS_Fij2_CF_/NC_
	* ( gdLgdLt_u_Rdd(s,tk,uk,q1,q2,mW2,mZ2)
	+ 2.gdLguL*t_u_Rud(s,tk,uk,q1,q2,q1h,q2h,mW2,mZ2)
	+ guLguLt_u_Ruu(s,tk,uk,q1h,q2h,mW2,mZ2)
	- 2.eZ/(s2-mW2) ( gdL
	* t_u_RZd(s,tk,uk,q1 ,q2 ,s2,mW2,mZ2)
	- guL
	* t_u_RZu(s,tk,uk,q1h,q2h,s2,mW2,mZ2)
	)
	+ eZ2/sqr(s2-mW2) *t_u_RZ(s,tk,uk,q1,q2,s2,mW2,mZ2)
	);
	swap(s,tk);
	swap(q2,w2);
	swap(q2h,w1);

	Val = -tk/s TR_/CF_;

	return Val;
	}
	/***************************************************************************/
	// t_u_M_R_gqb is the real emission g + qb -> n + q matrix element
	// exactly as defined in Eqs. C.9 of NPB 383(1992)3-44, multiplied by
	// tk * uk!
	Energy2 MEPP2VVPowheg::t_u_M_R_gqb(realVVKinematics R) const {
	// First the Born variables:
	Energy2 s2(R.s2r());
	Energy2 mW2(R.k12r());
	Energy2 mZ2(R.k22r());
	// Then the rest:
	Energy2 s(R.sr());
	Energy2 tk(R.tkr());
	Energy2 uk(R.ukr());
	Energy2 q1(R.q1r());
	Energy2 q2(R.q2r());
	Energy2 q1h(R.q1hatr());
	Energy2 q2h(R.q2hatr());
	Energy2 w1(R.w1r());
	Energy2 w2(R.w2r());

	double cosThetaW(sqrt(1.-sin2ThetaW_));
	double eZ2(eZ2_);
	double eZ(eZ_);
	double gdL(gdL_);
	double guL(guL_);
	double gdR(gdR_);
	double guR(guR_);

	// W+W-
	if(abs(mePartonData()[2]->id())==24&&abs(mePartonData()[3]->id())==24) {
	double e2(sqr(gW_)*sin2ThetaW_);
	if(abs(quark_->id())%2==0&&abs(antiquark_->id())%2==0) {
	// N.B. OLD eZ used to calculate new eZ2 then new eZ is set!
	if(quark_->id()==-antiquark_->id()) {
	eZ2 = 1./2.*sqr(s2-mW2)/Fij2_
	* (e2e2/s2/s2(sqr( 2./3.+eZ(guL+guR)/2./e2s2/(s2-mW2/sqr(cosThetaW)))
	+sqr( eZ(guL-guR)/2./e2s2/(s2-mW2/sqr(cosThetaW))))
	);
	eZ = -1./2./Fij2_/(gW_gW_/4./sqrt(Fij2_))(s2-mW2)
	* (gW_gW_e2/4./s2 ( 2./3.+2.eZguL/2./e2s2/(s2-mW2/sqr(cosThetaW))));
	} else {
	eZ2 =0.;
	eZ =0.;
	}
	gdL = gW_/sqrt(2.);
	guL = 0.;
	}
	else if(abs(quark_->id())%2==1&&abs(antiquark_->id())%2==1) {
	// N.B. OLD eZ used to calculate new eZ2 then new eZ is set!
	if(quark_->id()==-antiquark_->id()) {
	eZ2 = 1./2.*sqr(s2-mW2)/Fij2_
	* (e2e2/s2/s2(sqr(-1./3.+eZ(gdL+gdR)/2./e2s2/(s2-mW2/sqr(cosThetaW)))
	+sqr( eZ(gdL-gdR)/2./e2s2/(s2-mW2/sqr(cosThetaW))))
	);
	eZ = -1./2./Fij2_/(gW_gW_/4./sqrt(Fij2_))(s2-mW2)
	* (gW_gW_e2/4./s2 (-1./3.+2.eZgdL/2./e2s2/(s2-mW2/sqr(cosThetaW))));
	} else {
	eZ2 =0.;
	eZ =0.;
	}
	guL = gW_/sqrt(2.);
	gdL = 0.;
	}
	}
	// ZZ
	else if(mePartonData()[2]->id()==23&&mePartonData()[3]->id()==23) {
	eZ = 0.;
	eZ2 = 0.;
	double gV2,gA2;
	gV2 = sqr(guL/2.-gW_/2./cosThetaW2./3.sin2ThetaW_);
	gA2 = sqr(guL/2.+gW_/2./cosThetaW2./3.sin2ThetaW_);
	guL = sqrt(gV2gV2+gA2gA2+6.gA2gV2)/2.;
	gV2 = sqr(gdL/2.+gW_/2./cosThetaW1./3.sin2ThetaW_);
	gA2 = sqr(gdL/2.-gW_/2./cosThetaW1./3.sin2ThetaW_);
	gdL = sqrt(gV2gV2+gA2gA2+6.gA2gV2)/2.;
	if(abs(quark_->id())%2==0&&abs(antiquark_->id())%2==0) gdL = guL;
	else if(abs(quark_->id())%2==1&&abs(antiquark_->id())%2==1) guL = gdL;
	else {
	cout << "MEPP2VVPowheg:" << endl;
	cout << "ZZ needs 2 down-type / 2 up-type!" << endl;
	}
	}

	Energy2 Val(0.*GeV2);

	swap(s,uk);
	swap(q1,w1);
	swap(q1h,w2);
	Val = -2.pialphaS_Fij2_CF_/NC_
	* ( gdLgdLt_u_Rdd(s,tk,uk,q1,q2,mW2,mZ2)
	+ 2.gdLguL*t_u_Rud(s,tk,uk,q1,q2,q1h,q2h,mW2,mZ2)
	+ guLguLt_u_Ruu(s,tk,uk,q1h,q2h,mW2,mZ2)
	- 2.eZ/(s2-mW2) ( gdL
	* t_u_RZd(s,tk,uk,q1 ,q2 ,s2,mW2,mZ2)
	- guL
	* t_u_RZu(s,tk,uk,q1h,q2h,s2,mW2,mZ2)
	)
	+ eZ2/sqr(s2-mW2) *t_u_RZ(s,tk,uk,q1,q2,s2,mW2,mZ2)
	);
	swap(s,uk);
	swap(q1,w1);
	swap(q1h,w2);

	Val = -uk/s TR_/CF_;

	return Val;
	}

	/***************************************************************************/
	// The following six functions are I_{dd}^{(0)}, I_{ud}^{(0)},
	// I_{uu}^{(0)}, F_{u}^{(0)}, F_{d}^{(0)}, H^{(0)} from Eqs. 3.9 - 3.14
	// They make up the Born matrix element. Ixx functions correspond to the
	// graphs with no TGC, Fx functions are due to non-TGC graphs interfering
	// with TGC graphs, while the H function is due purely to TGC graphs.
	double Idd0(Energy2 s,Energy2 t,Energy2 u,Energy2 mW2,Energy2 mZ2);
	double Iud0(Energy2 s,Energy2 t,Energy2 u,Energy2 mW2,Energy2 mZ2);
	double Iuu0(Energy2 s,Energy2 t,Energy2 u,Energy2 mW2,Energy2 mZ2);
	Energy2 Fu0(Energy2 s,Energy2 t,Energy2 u,Energy2 mW2,Energy2 mZ2);
	Energy2 Fd0(Energy2 s,Energy2 t,Energy2 u,Energy2 mW2,Energy2 mZ2);
	Energy4 H0 (Energy2 s,Energy2 t,Energy2 u,Energy2 mW2,Energy2 mZ2);

	/***************************************************************************/
	// M_Born_WZ is the Born matrix element exactly as defined in Eqs. 3.3-3.14
	// of of NPB 383(1992)3-44 (with a spin*colour averaging factor 1./4./NC_/NC_).
	double MEPP2VVPowheg::M_Born_WZ(bornVVKinematics B) const {
	Energy2 s(B.sb());
	Energy2 t(B.tb());
	Energy2 u(B.ub());
	Energy2 mW2(B.k12b()); // N.B. the diboson masses are preserved in getting
	Energy2 mZ2(B.k22b()); // the 2->2 from the 2->3 kinematics.

	double cosThetaW(sqrt(1.-sin2ThetaW_));
	double eZ2(eZ2_);
	double eZ(eZ_);
	double gdL(gdL_);
	double guL(guL_);
	double gdR(gdR_);
	double guR(guR_);

	// W+W-
	if(abs(mePartonData()[2]->id())==24&&abs(mePartonData()[3]->id())==24) {
	double e2(sqr(gW_)*sin2ThetaW_);
	if(abs(quark_->id())%2==0&&abs(antiquark_->id())%2==0) {
	// N.B. OLD eZ used to calculate new eZ2 then new eZ is set!
	if(quark_->id()==-antiquark_->id()) {
	eZ2 = 1./2.*sqr(s-mW2)/Fij2_
	* (e2e2/s/s(sqr( 2./3.+eZ(guL+guR)/2./e2s/(s-mW2/sqr(cosThetaW)))
	+sqr( eZ(guL-guR)/2./e2s/(s-mW2/sqr(cosThetaW))))
	);
	eZ = -1./2./Fij2_/(gW_gW_/4./sqrt(Fij2_))(s-mW2)
	* (gW_gW_e2/4./s ( 2./3.+2.eZguL/2./e2s/(s-mW2/sqr(cosThetaW))));
	} else {
	eZ2 =0.;
	eZ =0.;
	}
	gdL = gW_/sqrt(2.);
	guL = 0.;
	}
	else if(abs(quark_->id())%2==1&&abs(antiquark_->id())%2==1) {
	// N.B. OLD eZ used to calculate new eZ2 then new eZ is set!
	if(quark_->id()==-antiquark_->id()) {
	eZ2 = 1./2.*sqr(s-mW2)/Fij2_
	* (e2e2/s/s(sqr(-1./3.+eZ(gdL+gdR)/2./e2s/(s-mW2/sqr(cosThetaW)))
	+sqr( eZ(gdL-gdR)/2./e2s/(s-mW2/sqr(cosThetaW))))
	);
	eZ = -1./2./Fij2_/(gW_gW_/4./sqrt(Fij2_))(s-mW2)
	* (gW_gW_e2/4./s (-1./3.+2.eZgdL/2./e2s/(s-mW2/sqr(cosThetaW))));
	} else {
	eZ2 =0.;
	eZ =0.;
	}
	guL = gW_/sqrt(2.);
	gdL = 0.;
	}
	}
	// ZZ
	else if(mePartonData()[2]->id()==23&&mePartonData()[3]->id()==23) {
	eZ = 0.;
	eZ2 = 0.;
	double gV2,gA2;
	gV2 = sqr(guL/2.-gW_/2./cosThetaW2./3.sin2ThetaW_);
	gA2 = sqr(guL/2.+gW_/2./cosThetaW2./3.sin2ThetaW_);
	guL = sqrt(gV2gV2+gA2gA2+6.gA2gV2)/2.;
	gV2 = sqr(gdL/2.+gW_/2./cosThetaW1./3.sin2ThetaW_);
	gA2 = sqr(gdL/2.-gW_/2./cosThetaW1./3.sin2ThetaW_);
	gdL = sqrt(gV2gV2+gA2gA2+6.gA2gV2)/2.;
	if(abs(quark_->id())%2==0&&abs(antiquark_->id())%2==0) gdL = guL;
	else if(abs(quark_->id())%2==1&&abs(antiquark_->id())%2==1) guL = gdL;
	else {
	cout << "MEPP2VVPowheg:" << endl;
	cout << "ZZ needs 2 down-type / 2 up-type!" << endl;
	}
	}

	return Fij2_/2./NC_
	* (
	gdLgdLIdd0(s,t,u,mW2,mZ2)
	+ 2.gdLguL*Iud0(s,t,u,mW2,mZ2)
	+ guLguLIuu0(s,t,u,mW2,mZ2)
	- 2.eZ/(s-mW2) ( gdL*Fd0(s,t,u,mW2,mZ2)
	- guL*Fu0(s,t,u,mW2,mZ2)
	)
	+ eZ2/sqr(s-mW2) * H0(s,t,u,mW2,mZ2)
	);
	}

	/***************************************************************************/
	double Idd0(Energy2 s, Energy2 t, Energy2 u, Energy2 mW2, Energy2 mZ2) {
	return 8.((ut/mW2/mZ2-1.)/4.+s/2.*(mW2+mZ2)/mW2/mZ2)
	+ 8.(u/t-mW2mZ2/t/t);
	}

	/***************************************************************************/
	double Iud0(Energy2 s, Energy2 t, Energy2 u, Energy2 mW2, Energy2 mZ2) {
	return - 8.((ut/mW2/mZ2-1.)/4.+s/2.*(mW2+mZ2)/mW2/mZ2)
	+ 8.s/t/u(mW2+mZ2);
	}

	/***************************************************************************/
	double Iuu0(Energy2 s, Energy2 t, Energy2 u, Energy2 mW2, Energy2 mZ2) {
	return Idd0(s,u,t,mW2,mZ2);
	}

	/***************************************************************************/
	Energy2 Fd0 (Energy2 s, Energy2 t, Energy2 u, Energy2 mW2, Energy2 mZ2) {
	return - 8.s( (ut/mW2/mZ2-1.)(1.-(mW2+mZ2)/s-4.mW2mZ2/s/t)/4.
	+ (mW2+mZ2)/2./mW2/mZ2(s-mW2-mZ2+2.mW2*mZ2/t)
	);
	}

	/***************************************************************************/
	Energy2 Fu0 (Energy2 s, Energy2 t, Energy2 u, Energy2 mW2, Energy2 mZ2) {
	return Fd0(s,u,t,mW2,mZ2);
	}

	/***************************************************************************/
	Energy4 H0 (Energy2 s, Energy2 t, Energy2 u, Energy2 mW2, Energy2 mZ2) {
	return 8.ss(ut/mW2/mZ2-1.)*( 1./4.-(mW2+mZ2)/2./s
	+ (sqr(mW2+mZ2)+8.mW2mZ2)/4./s/s
	)
	+ 8.ss(mW2+mZ2)/mW2/mZ2(s/2.-mW2-mZ2+sqr(mW2-mZ2)/2./s);
	}

	/***************************************************************************/
	bool MEPP2VVPowheg::sanityCheck() const {

	bool alarm(false);

	Energy2 prefacs(8.pialphaS_*S_.sr() /S_.xr() );
	Energy2 prefacsp(8.pialphaS_*SCp_.sr() /SCp_.xr() );
	Energy2 prefacsm(8.pialphaS_*SCm_.sr() /SCm_.xr() );
	Energy2 prefacp(8.pialphaS_*Cp_.sr()/Cp_.xr());
	Energy2 prefacm(8.pialphaS_*Cm_.sr()/Cm_.xr());

	double xp(Cp_.xr());
	double xm(Cm_.xr());

	double M_B_WW(M_Born_WW(B_));
	double M_B_ZZ(M_Born_ZZ(B_));
	double M_V_reg_WW(M_V_regular_WW(S_));
	double M_V_reg_ZZ(M_V_regular_ZZ(S_));
	Energy2 t_u_qqb_WW(t_u_M_R_qqb_WW(H_));
	Energy2 t_u_qqb_ZZ(t_u_M_R_qqb_ZZ(H_));

	// Check that the native leading order Herwig++ matrix
	// element is equivalent to the WZ leading order matrix
	// element in NPB 383 (1992) 3-44, with the relevant WZ->WW
	// WZ->ZZ transformation applied (M_Born_).
	// if(fabs((lo_me2_ - M_Born_)/M_Born_)>1.e-2) {
	// alarm=true;
	// cout << "lo_me2_ - M_Born_ (%) = "
	// << lo_me2_ - M_Born_ << " ("
	// << (lo_me2_ - M_Born_)/M_Born_*100. << ")\n";
	// }

	// Check that the transformation from NPB 383 (1992) 3-44 WZ
	// matrix elements to WW matrix elements actually works, by
	// comparing them to the explicit WW matrix elements in
	// NPB 410 (1993) 280-324.
	if(abs(mePartonData()[2]->id())==24&&abs(mePartonData()[3]->id())==24) {
	if(fabs((M_Born_ -M_B_WW )/M_B_WW )>1.e-6) {
	alarm=true;
	cout << "WZ->WW transformation error!\n";
	cout << "M_Born_ - M_B_WW (rel) = "
	<< M_Born_ - M_B_WW << " ("
	<< (M_Born_ - M_B_WW)/M_B_WW << ")\n";
	cout << "M_Born_ = " << M_Born_ << endl;
	cout << "M_B_WW = " << M_B_WW << endl;
	}
	if(fabs((M_V_regular_-M_V_reg_WW)/M_V_reg_WW)>1.e-6) {
	alarm=true;
	cout << "WZ->WW transformation error!\n";
	cout << "M_V_regular_ - M_V_reg_WW (rel) = "
	<< M_V_regular_ - M_V_reg_WW << " ("
	<< (M_V_regular_ - M_V_reg_WW)/M_V_reg_WW << ")\n";
	cout << "M_V_regular_ = " << M_V_regular_ << endl;
	cout << "M_V_reg_WW = " << M_V_reg_WW << endl;
	}
	if(fabs((t_u_M_R_qqb_-t_u_qqb_WW)/t_u_qqb_WW)>1.e-6) {
	alarm=true;
	cout << "WZ->WW transformation error!\n";
	cout << "t_u_M_R_qqb_ - t_u_qqb_WW (rel) = "
	<< (t_u_M_R_qqb_ - t_u_qqb_WW)/GeV2 << " ("
	<< (t_u_M_R_qqb_ - t_u_qqb_WW)/t_u_qqb_WW << ")\n";
	cout << "t_u_M_R_qqb_ = " << t_u_M_R_qqb_/GeV2 << endl;
	cout << "t_u_qqb_WW = " << t_u_qqb_WW /GeV2 << endl;
	}
	}

	// Check that the transformation from NPB 383 (1992) 3-44 WZ
	// matrix elements to ZZ matrix elements actually works, by
	// comparing them to the explicit ZZ matrix elements in
	// NPB 357 (1991) 409-438.
	if(abs(mePartonData()[2]->id())==23&&abs(mePartonData()[3]->id())==23) {
	if(fabs((M_Born_ -M_B_ZZ )/M_B_ZZ )>1.e-6) {
	alarm=true;
	cout << "WZ->ZZ transformation error!\n";
	cout << "M_Born_ - M_B_ZZ (rel) = "
	<< M_Born_ - M_B_ZZ << " ("
	<< (M_Born_ - M_B_ZZ)/M_B_ZZ << ")\n";
	cout << "M_Born_ = " << M_Born_ << endl;
	cout << "M_B_ZZ = " << M_B_ZZ << endl;
	}
	if(fabs((M_V_regular_-M_V_reg_ZZ)/M_V_reg_ZZ)>1.e-6) {
	alarm=true;
	cout << "WZ->ZZ transformation error!\n";
	cout << "M_V_regular_ - M_V_reg_ZZ (rel) = "
	<< M_V_regular_ - M_V_reg_ZZ << " ("
	<< (M_V_regular_ - M_V_reg_ZZ)/M_V_reg_ZZ << ")\n";
	cout << "M_V_regular_ = " << M_V_regular_ << endl;
	cout << "M_V_reg_ZZ = " << M_V_reg_ZZ << endl;
	}
	if(fabs((t_u_M_R_qqb_-t_u_qqb_ZZ)/t_u_qqb_ZZ)>1.e-6) {
	alarm=true;
	cout << "WZ->ZZ transformation error!\n";
	cout << "t_u_M_R_qqb_ - t_u_qqb_ZZ (rel) = "
	<< (t_u_M_R_qqb_ - t_u_qqb_ZZ)/GeV2 << " ("
	<< (t_u_M_R_qqb_ - t_u_qqb_ZZ)/t_u_qqb_ZZ << ")\n";
	cout << "t_u_M_R_qqb_ = " << t_u_M_R_qqb_/GeV2 << endl;
	cout << "t_u_qqb_ZZ = " << t_u_qqb_ZZ /GeV2 << endl;
	}
	}

	// Check the soft limit of the q + qbar matrix element.
	Energy2 absDiff_qqbs
	= t_u_M_R_qqb(S_) - prefacs2.CF_*M_Born_;
	double relDiff_qqbs = absDiff_qqbs / t_u_M_R_qqb(S_);
	if(fabs(relDiff_qqbs)>1.e-6) {
	alarm=true;
	cout << "\n";
	cout << "t_u_M_R_qqb(S_) " << t_u_M_R_qqb(S_) /GeV2 << endl;
	cout << "t_u_M_R_qqb(S_)-8pialphaSsHat/x2CabM_Born_ (rel):\n"
	<< absDiff_qqbs / GeV2 << " (" << relDiff_qqbs << ")\n";
	}

	// Check the positive soft-collinearlimit of the q + qbar matrix element.
	Energy2 absDiff_qqbsp
	= t_u_M_R_qqb(SCp_) - prefacsp2.CF_*M_Born_;
	double relDiff_qqbsp = absDiff_qqbsp / t_u_M_R_qqb(SCp_);
	if(fabs(relDiff_qqbsp)>1.e-6) {
	alarm=true;
	cout << "\n";
	cout << "t_u_M_R_qqb(SCp_) " << t_u_M_R_qqb(SCp_)/GeV2 << endl;
	cout << "t_u_M_R_qqb(SCp_)-8pialphaSsHat/x2CabM_Born_ (rel):\n"
	<< absDiff_qqbsp / GeV2 << " (" << relDiff_qqbsp << ")\n";
	}

	// Check the negative soft-collinearlimit of the q + qbar matrix element.
	Energy2 absDiff_qqbsm
	= t_u_M_R_qqb(SCm_) - prefacsm2.CF_*M_Born_;
	double relDiff_qqbsm = absDiff_qqbsm / t_u_M_R_qqb(SCm_);
	if(fabs(relDiff_qqbsm)>1.e-6) {
	alarm=true;
	cout << "\n";
	cout << "t_u_M_R_qqb(SCm_) " << t_u_M_R_qqb(SCm_)/GeV2 << endl;
	cout << "t_u_M_R_qqb(SCm_)-8pialphaSsHat/x2CabM_Born_ (rel):\n"
	<< absDiff_qqbsm / GeV2 << " (" << relDiff_qqbsm << ")\n";
	}

	// Check the positive collinearlimit of the q + qbar matrix element.
	Energy2 absDiff_qqbp
	= t_u_M_R_qqb(Cp_) - prefacpCF_(1.+xpxp)M_Born_;
	double relDiff_qqbp = absDiff_qqbp / t_u_M_R_qqb(Cp_);
	if(fabs(relDiff_qqbp)>1.e-6) {
	alarm=true;
	cout << "\n";
	cout << "t_u_M_R_qqb(Cp_) " << t_u_M_R_qqb(Cp_) /GeV2 << endl;
	cout << "t_u_M_R_qqb(Cp_)-8pialphaSsHat/x(1-x)PqqM_Born_ (rel):\n"
	<< absDiff_qqbp / GeV2 << " (" << relDiff_qqbp << ")\n";
	}

	// Check the negative collinearlimit of the q + qbar matrix element.
	Energy2 absDiff_qqbm
	= t_u_M_R_qqb(Cm_) - prefacmCF_(1.+xmxm)M_Born_;
	double relDiff_qqbm = absDiff_qqbm / t_u_M_R_qqb(Cm_);
	if(fabs(relDiff_qqbm)>1.e-6) {
	alarm=true;
	cout << "\n";
	cout << "t_u_M_R_qqb(Cm_) " << t_u_M_R_qqb(Cm_) /GeV2 << endl;
	cout << "t_u_M_R_qqb(Cm_)-8pialphaSsHat/x(1-x)PqqM_Born_ (rel):\n"
	<< absDiff_qqbm / GeV2 << " (" << relDiff_qqbm << ")\n";
	}

	// Check the positive collinear limit of the g + qbar matrix element.
	Energy2 absDiff_gqbp
	= t_u_M_R_gqb(Cp_) - prefacp(1.-xp)TR_(xpxp+sqr(1.-xp))*M_Born_;
	double relDiff_gqbp = absDiff_gqbp/ t_u_M_R_gqb(Cp_);
	if(fabs(relDiff_gqbp)>1.e-6) {
	alarm=true;
	cout << "\n";
	cout << "t_u_M_R_gqb(Cp_) " << t_u_M_R_gqb(Cp_) /GeV2 << endl;
	cout << "t_u_M_R_gqb(Cp_)-8pialphaSsHat/x(1-x)PgqM_Born_ (rel):\n"
	<< absDiff_gqbp / GeV2 << " (" << relDiff_gqbp << ")\n";
	}

	// Check the negative collinear limit of the q + g matrix element.
	Energy2 absDiff_qgm
	= t_u_M_R_qg(Cm_) - prefacm(1.-xm)TR_(xmxm+sqr(1.-xm))*M_Born_;
	double relDiff_qgm = absDiff_qgm / t_u_M_R_qg(Cm_);
	if(fabs(relDiff_qgm)>1.e-6) {
	alarm=true;
	cout << "\n";
	cout << "t_u_M_R_qg(Cm_) " << t_u_M_R_qg(Cm_) /GeV2 << endl;
	cout << "t_u_M_R_qg(Cm_)-8pialphaSsHat/x(1-x)PgqM_Born_ (rel):\n"
	<< absDiff_qgm / GeV2 << " (" << relDiff_qgm << ")\n";
	}

	return alarm;
	}

	/***************************************************************************/
	// M_Born_ZZ is the Born matrix element exactly as defined in Eqs. 2.18-2.19
	// of of NPB 357(1991)409-438.
	double MEPP2VVPowheg::M_Born_ZZ(bornVVKinematics B) const {
	Energy2 s(B.sb());
	Energy2 t(B.tb());
	Energy2 u(B.ub());
	Energy2 mZ2(B.k22b()); // the 2->2 from the 2->3 kinematics.
	double cosThetaW(sqrt(1.-sin2ThetaW_));

	double gV2,gA2,gX,gY,gZ;
	gV2 = sqr(guL_/2.-gW_/2./cosThetaW2./3.sin2ThetaW_);
	gA2 = sqr(guL_/2.+gW_/2./cosThetaW2./3.sin2ThetaW_);
	gX = sqrt(gV2gV2+gA2gA2+6.gA2gV2)/2.;
	gV2 = sqr(gdL_/2.+gW_/2./cosThetaW1./3.sin2ThetaW_);
	gA2 = sqr(gdL_/2.-gW_/2./cosThetaW1./3.sin2ThetaW_);
	gY = sqrt(gV2gV2+gA2gA2+6.gA2gV2)/2.;
	gZ = gX;
	if(abs(quark_->id())%2==1&&abs(antiquark_->id())%2==1) gZ = gY;

	return 1./NC_sqr(gZ2.)(t/u+u/t+4.mZ2s/t/u-mZ2mZ2*(1./t/t+1./u/u));

	}

	/***************************************************************************/
	// M_V_regular_ZZ is the one-loop ZZ matrix element exactly as defined in
	// Eqs. B.1 & B.2 of NPB 357(1991)409-438.
	double MEPP2VVPowheg::M_V_regular_ZZ(realVVKinematics S) const {
	Energy2 s(S.bornVariables().sb());
	Energy2 t(S.bornVariables().tb());
	Energy2 u(S.bornVariables().ub());
	Energy2 mZ2(S.k22r()); // the 2->2 from the 2->3 kinematics.
	double beta(S.betaxr()); // N.B. for x=1 \beta_x=\beta in NPB 383(1992)3-44.
	double cosThetaW(sqrt(1.-sin2ThetaW_));

	double gV2,gA2,gX,gY,gZ;
	gV2 = sqr(guL_/2.-gW_/2./cosThetaW2./3.sin2ThetaW_);
	gA2 = sqr(guL_/2.+gW_/2./cosThetaW2./3.sin2ThetaW_);
	gX = sqrt(gV2gV2+gA2gA2+6.gA2gV2)/2.;
	gV2 = sqr(gdL_/2.+gW_/2./cosThetaW1./3.sin2ThetaW_);
	gA2 = sqr(gdL_/2.-gW_/2./cosThetaW1./3.sin2ThetaW_);
	gY = sqrt(gV2gV2+gA2gA2+6.gA2gV2)/2.;
	gZ = gX;
	if(abs(quark_->id())%2==1&&abs(antiquark_->id())%2==1) gZ = gY;

	double M_V_reg(0.);
	M_V_reg = 2.ssqr(gZ2.)4.pialphaS_CF_/NC_/sqr(4.pi)/2.
	( 2.sqr(t+mZ2)/sqr(beta)/s/t/u + 4.*s/(t-mZ2)/u
	- ( 16.ttt+(28.s-68.mZ2)tt+(18.ss-36.mZ2s+88.mZ2mZ2)t
	+ 18.mZ2mZ2s-36.mZ2mZ2mZ2
	)/t/t/s/u
	+ ( 12.s/(t-mZ2)/u-4.mZ2s/sqr(t-mZ2)/u+2.(t+4.*s)/s/u
	- 6.(ss+mZ2mZ2)/s/t/u+6.mZ2mZ2(2.*mZ2-s)/t/t/s/u
	)*log(-t/mZ2)
	+ ( - ( 5.ttt+(8.s-18.mZ2)tt+(6.ss+25.mZ2mZ2)t
	+ 6.mZ2mZ2s-12.mZ2mZ2mZ2
	)/t/t/s/u
	- 12.mZ2sqr(t+mZ2)/sqr(sqr(beta))/s/s/t/u
	+ ( 3.tt-26.mZ2t-25.mZ2mZ2)/sqr(beta)/s/t/u
	)*log(s/mZ2)
	+ ( (-2.tt+8.mZ2t-2.ss-12.mZ2mZ2)/u + 4.mZ2mZ2(2.mZ2-s)/t/u)
	/ (s*t)
	* ( 2.sqr(log(-t/mZ2))-4.log(-t/mZ2)log((mZ2-t)/mZ2)-4.ReLi2(t/mZ2))
	+ ( 4.(tt-5.mZ2t+ss+10.mZ2*mZ2)/s/u
	+ 4.mZ2(-ss+2.mZ2s-10.mZ2*mZ2)/s/t/u
	+ 8.mZ2mZ2mZ2(2.*mZ2-s)/t/t/s/u
	)
	/ (t-mZ2)
	* (pipi/2.+log(-t/mZ2)log(-t/s)-1./2.*sqr(log(-t/mZ2)))
	+ ( ( (2.s-3.mZ2)tt+(6.mZ2mZ2-8.mZ2s)t+2.sss-4.mZ2s*s
	+ 12.mZ2mZ2s-3.mZ2mZ2mZ2
	) /s/t/u
	+ 12.mZ2mZ2*sqr(t+mZ2)/sqr(sqr(beta))/s/s/t/u
	- (mZ2tt-30.mZ2mZ2t-27.mZ2mZ2mZ2)/beta/beta/s/t/u
	)
	/ (beta*s)
	* (pipi/3.+sqr(log((1.-beta)/(1.+beta)))+4.ReLi2(-(1.-beta)/(1.+beta)))
	+ (4.(t+4.s-4.mZ2)/3./s/u+4.sqr(s-2.mZ2)/3./s/t/u)pi*pi
	);

	swap(t,u);
	M_V_reg += 2.ssqr(gZ2.)4.pialphaS_CF_/NC_/sqr(4.pi)/2.
	( 2.sqr(t+mZ2)/sqr(beta)/s/t/u + 4.*s/(t-mZ2)/u
	- ( 16.ttt+(28.s-68.mZ2)tt+(18.ss-36.mZ2s+88.mZ2mZ2)t
	+ 18.mZ2mZ2s-36.mZ2mZ2mZ2
	)/t/t/s/u
	+ ( 12.s/(t-mZ2)/u-4.mZ2s/sqr(t-mZ2)/u+2.(t+4.*s)/s/u
	- 6.(ss+mZ2mZ2)/s/t/u+6.mZ2mZ2(2.*mZ2-s)/t/t/s/u
	)*log(-t/mZ2)
	+ ( - ( 5.ttt+(8.s-18.mZ2)tt+(6.ss+25.mZ2mZ2)t
	+ 6.mZ2mZ2s-12.mZ2mZ2mZ2
	)/t/t/s/u
	- 12.mZ2sqr(t+mZ2)/sqr(sqr(beta))/s/s/t/u
	+ ( 3.tt-26.mZ2t-25.mZ2mZ2)/sqr(beta)/s/t/u
	)*log(s/mZ2)
	+ ( (-2.tt+8.mZ2t-2.ss-12.mZ2mZ2)/u + 4.mZ2mZ2(2.mZ2-s)/t/u)
	/ (s*t)
	* ( 2.sqr(log(-t/mZ2))-4.log(-t/mZ2)log((mZ2-t)/mZ2)-4.ReLi2(t/mZ2))
	+ ( 4.(tt-5.mZ2t+ss+10.mZ2*mZ2)/s/u
	+ 4.mZ2(-ss+2.mZ2s-10.mZ2*mZ2)/s/t/u
	+ 8.mZ2mZ2mZ2(2.*mZ2-s)/t/t/s/u
	)
	/ (t-mZ2)
	* (pipi/2.+log(-t/mZ2)log(-t/s)-1./2.*sqr(log(-t/mZ2)))
	+ ( ( (2.s-3.mZ2)tt+(6.mZ2mZ2-8.mZ2s)t+2.sss-4.mZ2s*s
	+ 12.mZ2mZ2s-3.mZ2mZ2mZ2
	) /s/t/u
	+ 12.mZ2mZ2*sqr(t+mZ2)/sqr(sqr(beta))/s/s/t/u
	- (mZ2tt-30.mZ2mZ2t-27.mZ2mZ2mZ2)/beta/beta/s/t/u
	)
	/ (beta*s)
	* (pipi/3.+sqr(log((1.-beta)/(1.+beta)))+4.ReLi2(-(1.-beta)/(1.+beta)))
	+ (4.(t+4.s-4.mZ2)/3./s/u+4.sqr(s-2.mZ2)/3./s/t/u)pi*pi
	);

	return M_V_reg;
	}

	/***************************************************************************/
	// t_u_M_R_qqb_ZZ is the real emission q + qb -> n + g matrix element
	// exactly as defined in Eqs. C.1 of NPB 357(1991)409-438, multiplied by
	// tk * uk!
	Energy2 MEPP2VVPowheg::t_u_M_R_qqb_ZZ(realVVKinematics R) const {
	// First the Born variables:
	Energy2 mZ2(R.k22r());
	// Then the rest:
	Energy2 s(R.sr());
	Energy2 tk(R.tkr());
	Energy2 uk(R.ukr());
	Energy2 q1(R.q1r());
	Energy2 q2(R.q2r());
	Energy2 q1h(R.q1hatr());
	Energy2 q2h(R.q2hatr());

	double cosThetaW(sqrt(1.-sin2ThetaW_));

	double gV2,gA2,gX,gY,gZ;
	gV2 = sqr(guL_/2.-gW_/2./cosThetaW2./3.sin2ThetaW_);
	gA2 = sqr(guL_/2.+gW_/2./cosThetaW2./3.sin2ThetaW_);
	gX = sqrt(gV2gV2+gA2gA2+6.gA2gV2)/2.;
	gV2 = sqr(gdL_/2.+gW_/2./cosThetaW1./3.sin2ThetaW_);
	gA2 = sqr(gdL_/2.-gW_/2./cosThetaW1./3.sin2ThetaW_);
	gY = sqrt(gV2gV2+gA2gA2+6.gA2gV2)/2.;
	gZ = gX;
	if(abs(quark_->id())%2==1&&abs(antiquark_->id())%2==1) gZ = gY;

	Energy2 t_u_qqb(0.*GeV2);
	t_u_qqb = (2.s)sqr(gZ2.)4.pialphaS_*CF_/NC_/2.
	* ( - ( tkukuk+2.sukuk-tktk*uk
	- 2.stkuk+mZ2(tktk-ukuk+2.suk-2.stk-2.ss)
	)/q1h/q1/q2h/s*tk
	+ 2.(tkukuk-mZ2uk(s+3.tk)+mZ2mZ2(2.*uk-s))/q1/q2/s
	+ ( tkuk(uk+s)-mZ2(ukuk+3.tkuk+3.suk+s*tk)
	+ 2.mZ2mZ2(uk+tk+2.s)
	)/q1h/q1/q2/s*tk
	+ ( tk(ukuk+tkuk-ss)+mZ2(4.suk-3.tkuk-tktk+4.ss)
	)/q1h/q2/s
	- ( tkuk+suk-stk-ss+2.mZ2(s-tk) ) /q1h/q1/s*tk
	+ q2(tkuk-suk-2.stk-2.s*s)/q1/q2h/s
	+ 2.(tkuk-tktk-stk-ss+mZ2(2.*s-uk))/q1/s
	- 2.mZ2(ukuk-2.mZ2uk+2.mZ2mZ2)/q1/q1/q2/stk
	+ (2.suk+tktk+3.stk+2s*s)/q1h/s
	+ q1(uk+s)(uk+tk)/q1h/q2h/s
	+ (tkuk+suk+3.stk+2.ss-mZ2(uk+tk+2.s))/q1h/q2h/s*uk
	+ (uk-tk)/2./q1h/q2h/s(q1(uk+s)/q2/tk-q2(tk+s)/q1/uk)tk*uk
	+ (tk-2.mZ2)(uk-2.mZ2)/q1h/q1/q2h/q2tk*uk
	- (q1q1+q2q2)/q1/q2
	- 2.mZ2(q2-2.mZ2)/q1/q1/stk
	);

	swap(tk ,uk );
	swap(q1 ,q2 );
	swap(q1h,q2h);
	t_u_qqb += (2.s)sqr(gZ2.)4.pialphaS_*CF_/NC_/2.
	* ( - ( tkukuk+2.sukuk-tktk*uk
	- 2.stkuk+mZ2(tktk-ukuk+2.suk-2.stk-2.ss)
	)/q1h/q1/q2h/s*tk
	+ 2.(tkukuk-mZ2uk(s+3.tk)+mZ2mZ2(2.*uk-s))/q1/q2/s
	+ ( tkuk(uk+s)-mZ2(ukuk+3.tkuk+3.suk+s*tk)
	+ 2.mZ2mZ2(uk+tk+2.s)
	)/q1h/q1/q2/s*tk
	+ ( tk(ukuk+tkuk-ss)+mZ2(4.suk-3.tkuk-tktk+4.ss)
	)/q1h/q2/s
	- ( tkuk+suk-stk-ss+2.mZ2(s-tk) ) /q1h/q1/s*tk
	+ q2(tkuk-suk-2.stk-2.s*s)/q1/q2h/s
	+ 2.(tkuk-tktk-stk-ss+mZ2(2.*s-uk))/q1/s
	- 2.mZ2(ukuk-2.mZ2uk+2.mZ2mZ2)/q1/q1/q2/stk
	+ (2.suk+tktk+3.stk+2s*s)/q1h/s
	+ q1(uk+s)(uk+tk)/q1h/q2h/s
	+ (tkuk+suk+3.stk+2.ss-mZ2(uk+tk+2.s))/q1h/q2h/s*uk
	+ (uk-tk)/2./q1h/q2h/s(q1(uk+s)/q2/tk-q2(tk+s)/q1/uk)tk*uk
	+ (tk-2.mZ2)(uk-2.mZ2)/q1h/q1/q2h/q2tk*uk
	- (q1q1+q2q2)/q1/q2
	- 2.mZ2(q2-2.mZ2)/q1/q1/stk
	);
	swap(tk ,uk );
	swap(q1 ,q2 );
	swap(q1h,q2h);

	swap(q1 ,q1h);
	swap(q2 ,q2h);
	t_u_qqb += (2.s)sqr(gZ2.)4.pialphaS_*CF_/NC_/2.
	* ( - ( tkukuk+2.sukuk-tktk*uk
	- 2.stkuk+mZ2(tktk-ukuk+2.suk-2.stk-2.ss)
	)/q1h/q1/q2h/s*tk
	+ 2.(tkukuk-mZ2uk(s+3.tk)+mZ2mZ2(2.*uk-s))/q1/q2/s
	+ ( tkuk(uk+s)-mZ2(ukuk+3.tkuk+3.suk+s*tk)
	+ 2.mZ2mZ2(uk+tk+2.s)
	)/q1h/q1/q2/s*tk
	+ ( tk(ukuk+tkuk-ss)+mZ2(4.suk-3.tkuk-tktk+4.ss)
	)/q1h/q2/s
	- ( tkuk+suk-stk-ss+2.mZ2(s-tk) ) /q1h/q1/s*tk
	+ q2(tkuk-suk-2.stk-2.s*s)/q1/q2h/s
	+ 2.(tkuk-tktk-stk-ss+mZ2(2.*s-uk))/q1/s
	- 2.mZ2(ukuk-2.mZ2uk+2.mZ2mZ2)/q1/q1/q2/stk
	+ (2.suk+tktk+3.stk+2s*s)/q1h/s
	+ q1(uk+s)(uk+tk)/q1h/q2h/s
	+ (tkuk+suk+3.stk+2.ss-mZ2(uk+tk+2.s))/q1h/q2h/s*uk
	+ (uk-tk)/2./q1h/q2h/s(q1(uk+s)/q2/tk-q2(tk+s)/q1/uk)tk*uk
	+ (tk-2.mZ2)(uk-2.mZ2)/q1h/q1/q2h/q2tk*uk
	- (q1q1+q2q2)/q1/q2
	- 2.mZ2(q2-2.mZ2)/q1/q1/stk
	);
	swap(q1 ,q1h);
	swap(q2 ,q2h);

	swap(tk ,uk );
	swap(q1 ,q2h);
	swap(q2 ,q1h);
	t_u_qqb += (2.s)sqr(gZ2.)4.pialphaS_*CF_/NC_/2.
	* ( - ( tkukuk+2.sukuk-tktk*uk
	- 2.stkuk+mZ2(tktk-ukuk+2.suk-2.stk-2.ss)
	)/q1h/q1/q2h/s*tk
	+ 2.(tkukuk-mZ2uk(s+3.tk)+mZ2mZ2(2.*uk-s))/q1/q2/s
	+ ( tkuk(uk+s)-mZ2(ukuk+3.tkuk+3.suk+s*tk)
	+ 2.mZ2mZ2(uk+tk+2.s)
	)/q1h/q1/q2/s*tk
	+ ( tk(ukuk+tkuk-ss)+mZ2(4.suk-3.tkuk-tktk+4.ss)
	)/q1h/q2/s
	- ( tkuk+suk-stk-ss+2.mZ2(s-tk) ) /q1h/q1/s*tk
	+ q2(tkuk-suk-2.stk-2.s*s)/q1/q2h/s
	+ 2.(tkuk-tktk-stk-ss+mZ2(2.*s-uk))/q1/s
	- 2.mZ2(ukuk-2.mZ2uk+2.mZ2mZ2)/q1/q1/q2/stk
	+ (2.suk+tktk+3.stk+2s*s)/q1h/s
	+ q1(uk+s)(uk+tk)/q1h/q2h/s
	+ (tkuk+suk+3.stk+2.ss-mZ2(uk+tk+2.s))/q1h/q2h/s*uk
	+ (uk-tk)/2./q1h/q2h/s(q1(uk+s)/q2/tk-q2(tk+s)/q1/uk)tk*uk
	+ (tk-2.mZ2)(uk-2.mZ2)/q1h/q1/q2h/q2tk*uk
	- (q1q1+q2q2)/q1/q2
	- 2.mZ2(q2-2.mZ2)/q1/q1/stk
	);
	swap(tk ,uk );
	swap(q1 ,q2h);
	swap(q2 ,q1h);

	return t_u_qqb;
	}

	/***************************************************************************/
	// M_B_WW is the Born matrix element exactly as defined in Eqs. 3.2-3.8
	// of of NPB 410(1993)280-384.
	double MEPP2VVPowheg::M_Born_WW(bornVVKinematics B) const {
	Energy2 s(B.sb());
	Energy2 t(B.tb());
	Energy2 u(B.ub());
	Energy2 mW2(B.k12b()); // N.B. the diboson masses are preserved in getting

	bool up_type = abs(quark_->id())%2==0 ? true : false;
	double Qi = up_type ? 2./3. : -1./3. ;
	double giL = up_type ? guL_/2. : gdL_/2.;
	double giR = up_type ? guR_/2. : gdR_/2.;
	double e2 = sqr(gW_)*sin2ThetaW_;

	double cos2ThetaW(1.-sin2ThetaW_);

	double ctt_i(gW_gW_gW_*gW_/16.);
	InvEnergy2 cts_i(gW_gW_e2/4./s (Qi+2.eZ_giL/e2s/(s-mW2/cos2ThetaW)));
	InvEnergy4 css_i(e2e2/s/s(sqr(Qi+eZ_(giL+giR)/e2s/(s-mW2/cos2ThetaW))
	+sqr( eZ_(giL-giR)/e2s/(s-mW2/cos2ThetaW)))
	);

	ctt_i = 8.Fij2_/gW_/gW_;
	cts_i = sqrt(8.Fij2_/gW_/gW_);
	if(quark_->id()!=-antiquark_->id()) {
	cts_i = 0./GeV2;
	css_i = 0./GeV2/GeV2;
	}

	if(!up_type) swap(t,u);
	double signf = up_type ? 1. : -1.;

	return 1./4./NC_
	* (
	ctt_i( 16.(ut/mW2/mW2-1.)(1./4.+mW2mW2/t/t)+16.s/mW2)
	- cts_i( 16.(ut/mW2/mW2-1.)(s/4.-mW2/2.-mW2*mW2/t)
	+ 16.s(s/mW2-2.+2.*mW2/t)
	)
	*signf
	+
	css_i( 8.(ut/mW2/mW2-1.)(ss/4.-smW2+3.mW2mW2)
	+ 8.ss*(s/mW2-4.)
	)
	);
	}

	/***************************************************************************/
	// M_V_regular_WW is the regular part of the one-loop WW matrix element
	// exactly as defined in Eqs. C.1 - C.7 of of NPB 410(1993)280-324 ***
	// modulo a factor 1/(2s) ***, which is a flux factor that those authors
	// absorb in the matrix element.
	double MEPP2VVPowheg::M_V_regular_WW(realVVKinematics S) const {
	Energy2 s(S.bornVariables().sb());
	Energy2 t(S.bornVariables().tb());
	Energy2 u(S.bornVariables().ub());
	Energy2 mW2(S.k12r()); // N.B. the diboson masses are preserved in getting
	double beta(S.betaxr()); // N.B. for x=1 \beta_x=\beta in NPB 383(1992)3-44.

	bool up_type = abs(quark_->id())%2==0 ? true : false;
	double Qi = up_type ? 2./3. : -1./3.;
	double giL = up_type ? guL_/2. : gdL_/2.;
	double giR = up_type ? guR_/2. : gdR_/2.;
	double e2 = sqr(gW_)*sin2ThetaW_;

	double cos2ThetaW(1.-sin2ThetaW_);

	double ctt_i(gW_gW_gW_*gW_/16.);
	InvEnergy2 cts_i(gW_gW_e2/4./s (Qi+2.eZ_giL/e2s/(s-mW2/cos2ThetaW)));
	InvEnergy4 css_i(e2e2/s/s(sqr(Qi+eZ_(giL+giR)/e2s/(s-mW2/cos2ThetaW))
	+sqr( eZ_(giL-giR)/e2s/(s-mW2/cos2ThetaW)))
	);

	ctt_i = 8.Fij2_/gW_/gW_;
	cts_i = sqrt(8.Fij2_/gW_/gW_);
	if(quark_->id()!=-antiquark_->id()) {
	cts_i = 0./GeV2;
	css_i = 0./GeV2/GeV2;
	}

	if(!up_type) swap(t,u);
	double signf = up_type ? 1. : -1.;

	InvEnergy4 TildeI4 = ( 2.sqr(log(-t/mW2))-4.log((mW2-t)/mW2)*log(-t/mW2)
	- 4.*ReLi2(t/mW2) )/s/t;
	InvEnergy2 TildeI3t = 1./(mW2-t)
	(sqr(log(mW2/s))/2.-sqr(log(-t/s))/2.-pipi/2.);
	InvEnergy2 TildeI3l = 1./s/beta( 4.ReLi2((beta-1.)/(beta+1.))
	+ sqr(log((1.-beta)/(1.+beta)))
	+ pi*pi/3.);
	double Fup1_st(0.);
	Fup1_st = 4.(80.tt+73.st-140.mW2t+72.mW2*mW2)/t/t
	- 4.sqr(4.t+s)/s/beta/beta/t
	- 128.(t+2.s)/mW2
	+ 64.t(t+s)/mW2/mW2
	- (32.(tt-3.st-3.mW2mW2)/t/t+128.s/(t-mW2))log(-t/mW2)
	+ ( 8.(6.tt+8.st-19.mW2t+12.mW2*mW2)/t/t
	- (32.tt-128.st-26.ss)/s/beta/beta/t
	+ 6.sqr(4.t+s)/s/sqr(sqr(beta))/t
	)*log(s/mW2)
	+ 32.s(2.mW2mW2/t-u)*TildeI4
	- 64.(t-mW2)(2.mW2mW2/t/t-u/t)*TildeI3t
	+ ( (16.t(4.mW2-u)-49.ss+72.mW2s-48.mW2*mW2)/2./t
	+ 2.(8.tt-14.st-3.s*s)/beta/beta/t
	- 3.sqr(4.t+s)/2./sqr(sqr(beta))/t
	)*TildeI3l
	+ 32./3.( 2.(t+2.*s)/mW2
	- (3.t+2.s-4.*mW2)/t
	- t*(t+s)/mW2/mW2
	)pipi;
	Energy2 Jup1_st(0.*GeV2);
	Jup1_st = -128.(tt+2.st+2.ss)/mW2
	- 16.(tt-21.st-26.mW2t+34.mW2s+17.mW2mW2)/t
	+ 64.st(t+s)/mW2/mW2 +32.s*s/(t-mW2)
	+ ( 16.(t-5.s+2.mW2)-48.mW2(2.s+mW2)/t
	+ 64.s(2.t+s)/(t-mW2) - 32.sst/sqr(t-mW2)
	)*log(-t/mW2)
	+ ( 16.(4.t+s)/beta/beta
	- 16.(3.t-2.*s)
	+ 48.mW2(2.t-2.s-mW2)/t
	)*log(s/mW2)
	+ 16.s(t(2.s+u)-2.mW2(2.s+mW2))TildeI4
	+ 32.(t-mW2)(2.mW2(2.s+mW2)/t-2.s-u)*TildeI3t
	+ ( 32.st-12.ss+32.mW2mW2
	- 16.mW2(2.t+7.s)-4.s(4.*t+s)/beta/beta
	)*TildeI3l
	+ 32./3.( 2.(tt+2.st+2.s*s)/mW2
	- st(t+s)/mW2/mW2-2.mW2(2.t-2.s-mW2)/t-t-4.*s
	)pipi;
	Energy4 Kup1_st(0.GeV2GeV2);
	Kup1_st = 16.( 12.tt+20.st-24.mW2t+17.ss-4.mW2s+12.mW2*mW2
	+ sst(t+s)/mW2/mW2-2.s(2.tt+3.st+2.s*s)/mW2)
	(2.-pipi/3.);

	return pialphaS_CF_/NC_/(sqr(4.*pi))
	* ( ctt_iFup1_st - cts_iJup1_stsignf + css_iKup1_st );
	}

	/***************************************************************************/
	// t_u_M_R_qqb is the real emission q + qb -> n + g matrix element
	// exactly as defined in Eqs. C.1 of NPB 383(1992)3-44, multiplied by
	// tk * uk!
	Energy2 MEPP2VVPowheg::t_u_M_R_qqb_WW(realVVKinematics R) const {
	// First the Born variables:
	Energy2 s2(R.s2r());
	Energy2 mW2(R.k12r());
	// Then the rest:
	Energy2 s(R.sr());
	Energy2 tk(R.tkr());
	Energy2 uk(R.ukr());
	Energy2 q1(R.q1r());
	Energy2 q2(R.q2r());
	Energy2 q1h(R.q1hatr());
	Energy2 q2h(R.q2hatr());

	bool up_type = abs(quark_->id())%2==0 ? true : false;
	double Qi = up_type ? 2./3. : -1./3.;
	double giL = up_type ? guL_/2. : gdL_/2.;
	double giR = up_type ? guR_/2. : gdR_/2.;
	double e2 = sqr(gW_)*sin2ThetaW_;

	double cos2ThetaW(1.-sin2ThetaW_);

	double ctt_i(gW_gW_gW_*gW_/16.);
	InvEnergy2 cts_i(gW_gW_e2/4./s2(Qi+2.eZ_giL/e2s2/(s2-mW2/cos2ThetaW)));
	InvEnergy4 css_i(e2e2/s2/s2(sqr(Qi+eZ_(giL+giR)/e2s2/(s2-mW2/cos2ThetaW))
	+sqr( eZ_(giL-giR)/e2s2/(s2-mW2/cos2ThetaW)))
	);

	ctt_i = 8.Fij2_/gW_/gW_;
	cts_i = sqrt(8.Fij2_/gW_/gW_);
	if(quark_->id()!=-antiquark_->id()) {
	cts_i = 0./GeV2;
	css_i = 0./GeV2/GeV2;
	}

	if(!up_type) {
	swap(q1,q1h);
	swap(q2,q2h);
	}
	double signf = up_type ? 1. : -1.;

	Energy2 t_u_Xup(0.*GeV2);
	Energy4 t_u_Yup(0.GeV2GeV2);
	Energy6 t_u_Zup(0.GeV2GeV2*GeV2);

	t_u_Xup = 32.mW2(tkuk+3.q2uk+q2s+q1q2)/q1/q2/q2tk
	+ 32.mW2q1/q2/q2*uk
	- 64.mW2s/q2
	- 32.tk(uk-q2)/q1/q2*tk
	+ 64.mW2mW2mW2/q1/q1/q2tk
	- 16.(2.tk-2.s-q2)/q2uk
	+ 16.s(2.s+2.q1+q2/2.)/q2
	- 8.(4.tk+uk+9.s+2.q2+2.q1)/mW2tk
	- 16.s(2.*s+q1)/mW2
	- 64.mW2mW2(tkuk+q2tk+q1uk-q2*s/2.)/q1/q2/q2
	+ 8.s2q1*(tk+s+q1)/mW2/mW2;
	swap(tk,uk);
	swap(q1,q2);
	t_u_Xup += 32.mW2(tkuk+3.q2uk+q2s+q1q2)/q1/q2/q2tk
	+ 32.mW2q1/q2/q2*uk
	- 64.mW2s/q2
	- 32.tk(uk-q2)/q1/q2*tk
	+ 64.mW2mW2mW2/q1/q1/q2tk
	- 16.(2.tk-2.s-q2)/q2uk
	+ 16.s(2.s+2.q1+q2/2.)/q2
	- 8.(4.tk+uk+9.s+2.q2+2.q1)/mW2tk
	- 16.s(2.*s+q1)/mW2
	- 64.mW2mW2(tkuk+q2tk+q1uk-q2*s/2.)/q1/q2/q2
	+ 8.s2q1*(tk+s+q1)/mW2/mW2;
	swap(tk,uk);
	swap(q1,q2);

	t_u_Yup = - 16.tk(uk(uk+s+q1)+q2(s-2.q1))/q1/q2tk
	- 32.mW2mW2*s/q2
	- 32.mW2mW2mW2/q1/q2tk
	+ 16.(2.q2uk+ss+q1s+5.q2s+q1q2+2.q2q2)/q2*tk
	- 16.(q2q2+ss-q2s)/q1*tk
	+ 16.s(q1s+3./2.q2s+q1q2-q1*q1)/q2
	+ 16.mW2tk(4.uk+s+q1-2.q2)/q1/q2tk
	+ 16.mW2(3.suk+q1uk-q1s-3.q2s-q1q1+q2q2)/q1/q2*tk
	+ 16.mW2s(q2-4.s+2.*q1)/q2
	- 8.s2(4.tk+uk+9.s+4.q1+2.q2)/mW2*tk
	- 16.s2(2.ss+2.q1s+q1*q1)/mW2
	- 32.mW2mW2(tk+uk/2.+2.s-q1)/q1/q2*tk
	+ 8.s2s2q1(tk+s+q1)/mW2/mW2;
	swap(tk,uk);
	swap(q1,q2);
	t_u_Yup += - 16.tk(uk(uk+s+q1)+q2(s-2.q1))/q1/q2tk
	- 32.mW2mW2*s/q2
	- 32.mW2mW2mW2/q1/q2tk
	+ 16.(2.q2uk+ss+q1s+5.q2s+q1q2+2.q2q2)/q2*tk
	- 16.(q2q2+ss-q2s)/q1*tk
	+ 16.s(q1s+3./2.q2s+q1q2-q1*q1)/q2
	+ 16.mW2tk(4.uk+s+q1-2.q2)/q1/q2tk
	+ 16.mW2(3.suk+q1uk-q1s-3.q2s-q1q1+q2q2)/q1/q2*tk
	+ 16.mW2s(q2-4.s+2.*q1)/q2
	- 8.s2(4.tk+uk+9.s+4.q1+2.q2)/mW2*tk
	- 16.s2(2.ss+2.q1s+q1*q1)/mW2
	- 32.mW2mW2(tk+uk/2.+2.s-q1)/q1/q2*tk
	+ 8.s2s2q1(tk+s+q1)/mW2/mW2;
	swap(tk,uk);
	swap(q1,q2);

	t_u_Zup = 8.s2(9.tk+3.uk+20.s+10.q1+4.q2)tk
	+ 8.s2(17./2.ss+10.q1s+6.q1q1)
	- 4.s2s2(4.tk+uk+9.s+6.q1+2.q2)/mW2tk
	- 8.s2s2(2.ss+3.q1s+2.q1*q1)/mW2
	- 16.mW2(2.tk+5.uk+7.s+6.q1+6.q2)tk
	- 16.mW2s(s+6.q1)
	+ 4.s2s2s2q1*(tk+s+q1)/mW2/mW2
	+ 48.mW2mW2*s2;
	swap(tk,uk);
	swap(q1,q2);
	t_u_Zup += 8.s2(9.tk+3.uk+20.s+10.q1+4.q2)tk
	+ 8.s2(17./2.ss+10.q1s+6.q1q1)
	- 4.s2s2(4.tk+uk+9.s+6.q1+2.q2)/mW2tk
	- 8.s2s2(2.ss+3.q1s+2.q1*q1)/mW2
	- 16.mW2(2.tk+5.uk+7.s+6.q1+6.q2)tk
	- 16.mW2s(s+6.q1)
	+ 4.s2s2s2q1*(tk+s+q1)/mW2/mW2
	+ 48.mW2mW2*s2;
	swap(tk,uk);
	swap(q1,q2);

	return -pialphaS_CF_/NC_
	* ( ctt_it_u_Xup - cts_it_u_Yupsignf + css_it_u_Zup );

	}

	/***************************************************************************/
	// The game here is to get this helicity amplitude squared to return all the
	// same values as t_u_M_R_qqb above, TIMES a further factor tk*uk!
	Energy2 MEPP2VVPowheg::t_u_M_R_qqb_hel_amp(realVVKinematics R) const {
	using namespace ThePEG::Helicity;

	// qqb_hel_amps_.reset(ProductionMatrixElement(PDT::Spin1Half,PDT::Spin1Half,
	// PDT::Spin1,PDT::Spin1,
	// PDT::Spin1));

	double sum_hel_amps_sqr(0.);

	tcPDPtr p1data(quark_);
	tcPDPtr p2data(antiquark_);
	tcPDPtr k1data(mePartonData()[2]);
	tcPDPtr k2data(mePartonData()[3]);
	tcPDPtr kdata(getParticleData(ParticleID::g));
	if(k1data->id()==-24&&k2data->id()==24) swap(k1data,k2data);

	SpinorWaveFunction qSpinor(R.p1r(),p1data,incoming);
	SpinorBarWaveFunction qbSpinor(R.p2r(),p2data,incoming);
	vector<SpinorWaveFunction> q;
	vector<SpinorBarWaveFunction> qb;
	for(unsigned int ix=0;ix<2;ix++) {
	qSpinor.reset(ix);
	qbSpinor.reset(ix);
	q.push_back(qSpinor);
	qb.push_back(qbSpinor);
	}

	VectorWaveFunction v1Polarization(R.k1r(),k1data,outgoing);
	VectorWaveFunction v2Polarization(R.k2r(),k2data,outgoing);
	vector<VectorWaveFunction> v1;
	vector<VectorWaveFunction> v2;
	for(unsigned int ix=0;ix<3;ix++) {
	v1Polarization.reset(ix);
	v2Polarization.reset(ix);
	v1.push_back(v1Polarization);
	v2.push_back(v2Polarization);
	}

	VectorWaveFunction gPolarization(R.kr(),kdata,outgoing);
	vector<VectorWaveFunction> g;
	for(unsigned int ix=0;ix<3;ix+=2) {
	gPolarization.reset(ix);
	g.push_back(gPolarization);
	}

	AbstractFFVVertexPtr ffg = FFGvertex_;
	AbstractFFVVertexPtr ffv1 = k1data->id()==23 ? FFZvertex_ : FFWvertex_;
	AbstractFFVVertexPtr ffv2 = k2data->id()==23 ? FFZvertex_ : FFWvertex_;

	// Collecting information for intermediate fermions
	vector<tcPDPtr> tc;
	if(abs(k1data->id())==24&&abs(k2data->id())==24) {
	if(abs(p1data->id())%2==0)
	for(int ix=0;ix<3;++ix) tc.push_back(getParticleData(1+2*ix));
	else
	for(int ix=0;ix<3;++ix) tc.push_back(getParticleData(2+2*ix));
	}
	else if(k1data->id()==23&&k2data->id()==23) tc.push_back(p1data);
	else if(abs(k1data->id())==24&&k2data->id()==23) tc.push_back(p2data);

	// Loop over helicities summing the relevant diagrams
	for(unsigned int p1hel=0;p1hel<2;++p1hel) {
	for(unsigned int p2hel=0;p2hel<2;++p2hel) {
	for(unsigned int khel=0;khel<2;++khel) {
	SpinorWaveFunction p1_k = ffg->evaluate(mu_UV2(),5,p1data,q[p1hel],g[khel]);
	SpinorBarWaveFunction p2_k = ffg->evaluate(mu_UV2(),5,p2data,qb[p2hel],g[khel]);
	for(unsigned int k1hel=0;k1hel<3;++k1hel) {
	for(unsigned int k2hel=0;k2hel<3;++k2hel) {
	// If helicity is exactly conserved (massless quarks) skip if p1hel=p2hel
	// but if the production ME is required first fill it with (0.,0.).
	if((p1hel==p2hel)&&helicityConservation_) {
	// if(getMatrix) {
	// if(khel==0)
	// qqb_hel_amps_(p1hel,p2hel,k1hel,k2hel,0) = Complex(0.,0.);
	// else
	// qqb_hel_amps_(p1hel,p2hel,k1hel,k2hel,2) = Complex(0.,0.);
	// }
	continue;
	}
	vector<Complex> diagrams;
	// Get all t-channel diagram contributions
	tcPDPtr intermediate_t;
	for(unsigned int ix=0;ix<tc.size();ix++) {
	intermediate_t = (!(k1data->id()==24&&k2data->id()==-24)) ? p2data : tc[ix];
	SpinorWaveFunction p1_v1 = ffv1->evaluate(scale(),5,intermediate_t,q[p1hel],v1[k1hel]);
	SpinorBarWaveFunction p2_v2 = ffv2->evaluate(scale(),5,intermediate_t,qb[p2hel],v2[k2hel]);
	// First calculate all the off-shell fermion currents
	// Now calculate the 6 t-channel diagrams
	// q+qb->g+v1+v2, q+qb->v1+g+v2, q+qb->v1+v2+g
	if(!((k1data->id()==24&&k2data->id()==-24)&&(abs(p1data->id())%2==1))) {
	diagrams.push_back(ffv1->evaluate(scale(),p1_k,p2_v2,v1[k1hel]));
	diagrams.push_back(ffg->evaluate(mu_UV2(),p1_v1,p2_v2,g[khel]));
	diagrams.push_back(ffv2->evaluate(scale(),p1_v1,p2_k,v2[k2hel]));
	}
	intermediate_t = (!(k1data->id()==24&&k2data->id()==-24)) ? p1data : tc[ix];
	SpinorWaveFunction p1_v2 = ffv2->evaluate(scale(),5,intermediate_t,q[p1hel],v2[k2hel]);
	SpinorBarWaveFunction p2_v1 = ffv1->evaluate(scale(),5,intermediate_t,qb[p2hel],v1[k1hel]);
	// q+qb->g+v2+v1, q+qb->v2+g+v1, q+qb->v2+v1+g
	if(!((k1data->id()==24&&k2data->id()==-24)&&(abs(p1data->id())%2==0))) {
	diagrams.push_back(ffv2->evaluate(scale(),p1_k,p2_v1,v2[k2hel]));
	diagrams.push_back(ffg->evaluate(mu_UV2(),p1_v2,p2_v1,g[khel]));
	diagrams.push_back(ffv1->evaluate(scale(),p1_v2,p2_k,v1[k1hel]));
	}
	}
	// Note: choosing 3 as the second argument in WWWvertex_->evaluate()
	// sets option 3 in thepeg/Helicity/Vertex/VertexBase.cc , which
	// means the propagator does not contain a width factor (which is
	// good re. gauge invariance).
	// If W+Z / W-Z calculate the two V+jet-like s-channel diagrams
	if(abs(k1data->id())==24&&k2data->id()==23) {
	// The off-shell s-channel boson current
	VectorWaveFunction k1_k2 =
	WWWvertex_->evaluate(scale(),3,k1data->CC(),v2[k2hel],v1[k1hel]);
	// q+qb->g+v1->g+v1+v2, q+qb->v1+g->v1+v2+g
	diagrams.push_back(ffv1->evaluate(scale(),p1_k,qb[p2hel],k1_k2));
	diagrams.push_back(ffv1->evaluate(scale(),q[p1hel],p2_k,k1_k2));
	}
	// If W+W- calculate the four V+jet-like s-channel diagrams
	if((k1data->id()==24&&k2data->id()==-24)&&(p1data->id()==-p2data->id())) {
	// The off-shell s-channel boson current
	VectorWaveFunction k1_k2;
	// q+qb->g+Z0->g+v1+v2,q+qb->Z0+g->v1+v2+g,
	tcPDPtr Z0 = getParticleData(ParticleID::Z0);
	k1_k2 = WWWvertex_->evaluate(scale(),3,Z0,v2[k2hel],v1[k1hel]);
	diagrams.push_back(FFZvertex_->evaluate(scale(),p1_k,qb[p2hel],k1_k2));
	diagrams.push_back(FFZvertex_->evaluate(scale(),q[p1hel],p2_k,k1_k2));
	// q+qb->g+gamma->g+v1+v2,q+qb->gamma+g->v1+v2+g,
	tcPDPtr gamma = getParticleData(ParticleID::gamma);
	k1_k2 = WWWvertex_->evaluate(scale(),3,gamma,v2[k2hel],v1[k1hel]);
	diagrams.push_back(FFPvertex_->evaluate(scale(),p1_k,qb[p2hel],k1_k2));
	diagrams.push_back(FFPvertex_->evaluate(scale(),q[p1hel],p2_k,k1_k2));
	}
	// Add up all diagrams to get the total amplitude:
	Complex hel_amp(0.);
	for(unsigned int ix=0;ix<diagrams.size();ix++) hel_amp += diagrams[ix];
	// If we need to fill the production ME we do it here:
	// if(getMatrix) {
	// if(khel==0)
	// qqb_hel_amps_(p1hel,p2hel,k1hel,k2hel,0) = hel_amp;
	// else
	// qqb_hel_amps_(p1hel,p2hel,k1hel,k2hel,2) = hel_amp;
	// }
	sum_hel_amps_sqr += norm(hel_amp);
	}
	}
	}
	}
	}

	// Fill up the remaining bits of the production ME, corresponding
	// to longitudinal gluon polarization, with (0.,0.).
	// if(getMatrix) {
	// for(unsigned int p1hel=0;p1hel<2;++p1hel) {
	// for(unsigned int p2hel=0;p2hel<2;++p2hel) {
	// for(unsigned int k1hel=0;k1hel<3;++k1hel) {
	// for(unsigned int k2hel=0;k2hel<3;++k2hel) {
	// qqb_hel_amps_(p1hel,p2hel,k1hel,k2hel,1) = Complex(0.,0.);
	// }
	// }
	// }
	// }
	// }

	// Spin and colour averaging factors = 1/4 * CF * 1/3 = 1/9
	sum_hel_amps_sqr /= 9.;

	// Symmetry factor for identical Z bosons in the final state
	if(k1data->id()==23&&k2data->id()==23) sum_hel_amps_sqr /= 2.;

	return sum_hel_amps_sqrR.tkr()R.ukr()*UnitRemoval::InvE2;
	}

	/***************************************************************************/
	// The game here is to get this helicity amplitude squared to return all the
	// same values as t_u_M_R_qg above, TIMES a further factor tk*uk!
	Energy2 MEPP2VVPowheg::t_u_M_R_qg_hel_amp(realVVKinematics R) const {
	using namespace ThePEG::Helicity;

	// qg_hel_amps_.reset(ProductionMatrixElement(PDT::Spin1Half,PDT::Spin1,
	// PDT::Spin1,PDT::Spin1,
	// PDT::Spin1Half));

	double sum_hel_amps_sqr(0.);

	tcPDPtr p1data(quark_);
	tcPDPtr p2data(getParticleData(ParticleID::g));
	tcPDPtr k1data(mePartonData()[2]);
	tcPDPtr k2data(mePartonData()[3]);
	tcPDPtr kdata (antiquark_->CC());
	if(k1data->id()==-24&&k2data->id()==24) swap(k1data,k2data);

	SpinorWaveFunction qinSpinor(R.p1r(),p1data,incoming);
	SpinorBarWaveFunction qoutSpinor(R.kr(),kdata,outgoing);
	vector<SpinorWaveFunction> qin;
	vector<SpinorBarWaveFunction> qout;
	for(unsigned int ix=0;ix<2;ix++) {
	qinSpinor.reset(ix);
	qoutSpinor.reset(ix);
	qin.push_back(qinSpinor);
	qout.push_back(qoutSpinor);
	}

	VectorWaveFunction v1Polarization(R.k1r(),k1data,outgoing);
	VectorWaveFunction v2Polarization(R.k2r(),k2data,outgoing);
	vector<VectorWaveFunction> v1;
	vector<VectorWaveFunction> v2;
	for(unsigned int ix=0;ix<3;ix++) {
	v1Polarization.reset(ix);
	v2Polarization.reset(ix);
	v1.push_back(v1Polarization);
	v2.push_back(v2Polarization);
	}

	VectorWaveFunction gPolarization(R.p2r(),p2data,incoming);
	vector<VectorWaveFunction> g;
	for(unsigned int ix=0;ix<3;ix+=2) {
	gPolarization.reset(ix);
	g.push_back(gPolarization);
	}

	AbstractFFVVertexPtr ffg = FFGvertex_;
	AbstractFFVVertexPtr ffv1 = k1data->id()==23 ? FFZvertex_ : FFWvertex_;
	AbstractFFVVertexPtr ffv2 = k2data->id()==23 ? FFZvertex_ : FFWvertex_;

	// Collecting information for intermediate fermions
	vector<tcPDPtr> tc;
	if(abs(k1data->id())==24&&abs(k2data->id())==24) {
	if(abs(p1data->id())%2==0)
	for(int ix=0;ix<3;++ix) tc.push_back(getParticleData(1+2*ix));
	else
	for(int ix=0;ix<3;++ix) tc.push_back(getParticleData(2+2*ix));
	}
	else if(k1data->id()==23&&k2data->id()==23) tc.push_back(p1data);
	else if(abs(k1data->id())==24&&k2data->id()==23) tc.push_back(kdata->CC());

	// Loop over helicities summing the relevant diagrams
	for(unsigned int p1hel=0;p1hel<2;++p1hel) {
	for(unsigned int p2hel=0;p2hel<2;++p2hel) {
	for(unsigned int khel=0;khel<2;++khel) {
	SpinorWaveFunction p1_p2 = ffg->evaluate(mu_UV2(),5,p1data,qin[p1hel],g[p2hel]);
	SpinorBarWaveFunction p2_k = ffg->evaluate(mu_UV2(),5,kdata->CC(),qout[khel],g[p2hel]);
	for(unsigned int k1hel=0;k1hel<3;++k1hel) {
	for(unsigned int k2hel=0;k2hel<3;++k2hel) {
	// If helicity is exactly conserved (massless quarks) skip if p1hel!=khel
	// but if the production ME is required first fill it with (0.,0.).
	if((p1hel!=khel)&&helicityConservation_) {
	// if(getMatrix) {
	// if(p2hel==0)
	// qg_hel_amps_(p1hel,0,k1hel,k2hel,khel) = Complex(0.,0.);
	// else
	// qg_hel_amps_(p1hel,2,k1hel,k2hel,khel) = Complex(0.,0.);
	// }
	continue;
	}
	vector<Complex> diagrams;
	// Get all t-channel diagram contributions
	tcPDPtr intermediate_q;
	for(unsigned int ix=0;ix<tc.size();ix++) {
	intermediate_q = (!(k1data->id()==24&&k2data->id()==-24)) ? antiquark_ : tc[ix];
	SpinorWaveFunction p1_v1 = ffv1->evaluate(scale(),5,intermediate_q,qin[p1hel],v1[k1hel]);
	SpinorBarWaveFunction k_v2 = ffv2->evaluate(scale(),5,intermediate_q,qout[khel],v2[k2hel]);
	// First calculate all the off-shell fermion currents
	// Now calculate the 6 abelian diagrams
	// q+g->v1+v2+q with 2 t-channel propagators, 1 s- and 1 t-channel and 2 t-channel ones.
	if(!((k1data->id()==24&&k2data->id()==-24)&&(abs(p1data->id())%2==1))) {
	diagrams.push_back(ffv2->evaluate(scale(),p1_v1,p2_k,v2[k2hel]));
	diagrams.push_back(ffg->evaluate(mu_UV2(),p1_v1,k_v2,g[p2hel]));
	diagrams.push_back(ffv1->evaluate(scale(),p1_p2,k_v2,v1[k1hel]));
	}
	intermediate_q = (!(k1data->id()==24&&k2data->id()==-24)) ? p1data : tc[ix];
	SpinorWaveFunction p1_v2 = ffv2->evaluate(scale(),5,intermediate_q,qin[p1hel],v2[k2hel]);
	SpinorBarWaveFunction k_v1 = ffv1->evaluate(scale(),5,intermediate_q,qout[khel],v1[k1hel]);
	// q+g->v2+v1+q, with 2 t-channel propagators, 1 s- and 1 t-channel and 2 t-channel ones.
	if(!((k1data->id()==24&&k2data->id()==-24)&&(abs(p1data->id())%2==0))) {
	diagrams.push_back(ffv1->evaluate(scale(),p1_v2,p2_k,v1[k1hel]));
	diagrams.push_back(ffg->evaluate(mu_UV2(),p1_v2,k_v1,g[p2hel]));
	diagrams.push_back(ffv2->evaluate(scale(),p1_p2,k_v1,v2[k2hel]));
	}
	}
	// If W+Z / W-Z calculate the two V+jet-like s-channel diagrams
	if(abs(k1data->id())==24&&k2data->id()==23) {
	// The off-shell s-channel boson current
	VectorWaveFunction k1_k2 =
	WWWvertex_->evaluate(scale(),3,k1data->CC(),v2[k2hel],v1[k1hel]);
	// q+qb->g+v1->g+v1+v2, q+qb->v1+g->v1+v2+g
	diagrams.push_back(ffv1->evaluate(scale(),p1_p2,qout[khel],k1_k2));
	diagrams.push_back(ffv1->evaluate(scale(),qin[p1hel],p2_k,k1_k2));
	}
	// If W+W- calculate the four V+jet-like s-channel diagrams
	if((k1data->id()==24&&k2data->id()==-24)&&(p1data->id()==kdata->id())) {
	// The off-shell s-channel boson current
	VectorWaveFunction k1_k2;
	// q+qb->g+Z0->g+v1+v2,q+qb->Z0+g->v1+v2+g,
	tcPDPtr Z0 = getParticleData(ParticleID::Z0);
	k1_k2 = WWWvertex_->evaluate(scale(),3,Z0,v2[k2hel],v1[k1hel]);
	diagrams.push_back(FFZvertex_->evaluate(scale(),p1_p2,qout[khel],k1_k2));
	diagrams.push_back(FFZvertex_->evaluate(scale(),qin[p1hel],p2_k,k1_k2));
	// q+qb->g+gamma->g+v1+v2,q+qb->gamma+g->v1+v2+g,
	tcPDPtr gamma = getParticleData(ParticleID::gamma);
	k1_k2 = WWWvertex_->evaluate(scale(),3,gamma,v2[k2hel],v1[k1hel]);
	diagrams.push_back(FFPvertex_->evaluate(scale(),p1_p2,qout[khel],k1_k2));
	diagrams.push_back(FFPvertex_->evaluate(scale(),qin[p1hel],p2_k,k1_k2));
	}
	// Add up all diagrams to get the total amplitude:
	Complex hel_amp(0.);
	for(unsigned int ix=0;ix<diagrams.size();ix++) hel_amp += diagrams[ix];
	// If we need to fill the production ME we do it here:
	// if(getMatrix) {
	// if(p2hel==0)
	// qg_hel_amps_(p1hel,0,k1hel,k2hel,khel) = hel_amp;
	// else
	// qg_hel_amps_(p1hel,2,k1hel,k2hel,khel) = hel_amp;
	// }
	sum_hel_amps_sqr += norm(hel_amp);
	}
	}
	}
	}
	}

	// Fill up the remaining bits of the production ME, corresponding
	// to longitudinal gluon polarization, with (0.,0.).
	// if(getMatrix) {
	// for(unsigned int p1hel=0;p1hel<2;++p1hel) {
	// for(unsigned int k1hel=0;k1hel<3;++k1hel) {
	// for(unsigned int k2hel=0;k2hel<3;++k2hel) {
	// for(unsigned int khel=0;khel<2;++khel) {
	// qg_hel_amps_(p1hel,1,k1hel,k2hel,khel) = Complex(0.,0.);
	// }
	// }
	// }
	// }
	// }

	// Spin and colour averaging factors = 1/4 * TR * 1/3 = 1/24
	sum_hel_amps_sqr /= 24.;

	// Symmetry factor for identical Z bosons in the final state
	if(k1data->id()==23&&k2data->id()==23) sum_hel_amps_sqr /= 2.;

	return sum_hel_amps_sqrR.tkr()R.ukr()*UnitRemoval::InvE2;
	}

	/***************************************************************************/
	// The game here is to get this helicity amplitude squared to return all the
	// same values as t_u_M_R_gqb above, TIMES a further factor tk*uk!
	Energy2 MEPP2VVPowheg::t_u_M_R_gqb_hel_amp(realVVKinematics R) const {
	using namespace ThePEG::Helicity;

	// gqb_hel_amps_.reset(ProductionMatrixElement(PDT::Spin1,PDT::Spin1Half,
	// PDT::Spin1,PDT::Spin1,
	// PDT::Spin1Half));

	double sum_hel_amps_sqr(0.);

	tcPDPtr p1data(getParticleData(ParticleID::g));
	tcPDPtr p2data(antiquark_);
	tcPDPtr k1data(mePartonData()[2]);
	tcPDPtr k2data(mePartonData()[3]);
	tcPDPtr kdata (quark_->CC());
	if(k1data->id()==-24&&k2data->id()==24) swap(k1data,k2data);

	SpinorBarWaveFunction qbinSpinor(R.p2r(),p2data,incoming);
	SpinorWaveFunction qboutSpinor(R.kr(),kdata,outgoing);
	vector<SpinorBarWaveFunction> qbin;
	vector<SpinorWaveFunction> qbout;
	for(unsigned int ix=0;ix<2;ix++) {
	qbinSpinor.reset(ix);
	qboutSpinor.reset(ix);
	qbin.push_back(qbinSpinor);
	qbout.push_back(qboutSpinor);
	}

	VectorWaveFunction v1Polarization(R.k1r(),k1data,outgoing);
	VectorWaveFunction v2Polarization(R.k2r(),k2data,outgoing);
	vector<VectorWaveFunction> v1;
	vector<VectorWaveFunction> v2;
	for(unsigned int ix=0;ix<3;ix++) {
	v1Polarization.reset(ix);
	v2Polarization.reset(ix);
	v1.push_back(v1Polarization);
	v2.push_back(v2Polarization);
	}

	VectorWaveFunction gPolarization(R.p1r(),p1data,incoming);
	vector<VectorWaveFunction> g;
	for(unsigned int ix=0;ix<3;ix+=2) {
	gPolarization.reset(ix);
	g.push_back(gPolarization);
	}

	AbstractFFVVertexPtr ffg = FFGvertex_;
	AbstractFFVVertexPtr ffv1 = k1data->id()==23 ? FFZvertex_ : FFWvertex_;
	AbstractFFVVertexPtr ffv2 = k2data->id()==23 ? FFZvertex_ : FFWvertex_;

	// Collecting information for intermediate fermions
	vector<tcPDPtr> tc;
	if(abs(k1data->id())==24&&abs(k2data->id())==24) {
	if(abs(p2data->id())%2==0)
	for(int ix=0;ix<3;++ix) tc.push_back(getParticleData(1+2*ix));
	else
	for(int ix=0;ix<3;++ix) tc.push_back(getParticleData(2+2*ix));
	}
	else if(k1data->id()==23&&k2data->id()==23) tc.push_back(p2data);
	else if(abs(k1data->id())==24&&k2data->id()==23) tc.push_back(kdata->CC());

	// Loop over helicities summing the relevant diagrams
	for(unsigned int p1hel=0;p1hel<2;++p1hel) {
	for(unsigned int p2hel=0;p2hel<2;++p2hel) {
	for(unsigned int khel=0;khel<2;++khel) {
	SpinorBarWaveFunction p1_p2 = ffg->evaluate(mu_UV2(),5,p2data,qbin[p2hel],g[p1hel]);
	SpinorWaveFunction p1_k = ffg->evaluate(mu_UV2(),5,kdata->CC(),qbout[khel],g[p1hel]);
	for(unsigned int k1hel=0;k1hel<3;++k1hel) {
	for(unsigned int k2hel=0;k2hel<3;++k2hel) {
	// If helicity is exactly conserved (massless quarks) skip if p2hel!=khel
	// but if the production ME is required first fill it with (0.,0.).
	if((p2hel!=khel)&&helicityConservation_) {
	// if(getMatrix) {
	// if(p1hel==0)
	// gqb_hel_amps_(0,p2hel,k1hel,k2hel,khel) = Complex(0.,0.);
	// else
	// gqb_hel_amps_(2,p2hel,k1hel,k2hel,khel) = Complex(0.,0.);
	// }
	continue;
	}
	vector<Complex> diagrams;
	// Get all t-channel diagram contributions
	tcPDPtr intermediate_q;
	for(unsigned int ix=0;ix<tc.size();ix++) {
	intermediate_q = (!(k1data->id()==24&&k2data->id()==-24)) ? quark_ : tc[ix];
	SpinorBarWaveFunction p2_v1 = ffv1->evaluate(scale(),5,intermediate_q,qbin[p2hel],v1[k1hel]);
	SpinorWaveFunction k_v2 = ffv2->evaluate(scale(),5,intermediate_q,qbout[khel],v2[k2hel]);
	// First calculate all the off-shell fermion currents
	// Now calculate the 6 abelian diagrams q+g->v1+v2+q
	// with 2 t-channel propagators, 1 s- and 1 t-channel
	// and 2 t-channel ones.
	if(!((k1data->id()==24&&k2data->id()==-24)&&(abs(p2data->id())%2==0))) {
	diagrams.push_back(ffv2->evaluate(scale(),p1_k,p2_v1,v2[k2hel]));
	diagrams.push_back(ffg->evaluate(mu_UV2(),k_v2,p2_v1,g[p1hel]));
	diagrams.push_back(ffv1->evaluate(scale(),k_v2,p1_p2,v1[k1hel]));
	}
	intermediate_q = (!(k1data->id()==24&&k2data->id()==-24)) ? p2data : tc[ix];
	SpinorBarWaveFunction p2_v2 = ffv2->evaluate(scale(),5,intermediate_q,qbin[p2hel],v2[k2hel]);
	SpinorWaveFunction k_v1 = ffv1->evaluate(scale(),5,intermediate_q,qbout[khel],v1[k1hel]);
	// q+g->v2+v1+q, with 2 t-channel propagators, 1 s- and 1 t-channel and 2 t-channel ones.
	if(!((k1data->id()==24&&k2data->id()==-24)&&(abs(p2data->id())%2==1))) {
	diagrams.push_back(ffv1->evaluate(scale(),p1_k,p2_v2,v1[k1hel]));
	diagrams.push_back(ffg->evaluate(mu_UV2(),k_v1,p2_v2,g[p1hel]));
	diagrams.push_back(ffv2->evaluate(scale(),k_v1,p1_p2,v2[k2hel]));
	}
	}
	// If W+Z / W-Z calculate the two V+jet-like s-channel diagrams
	if(abs(k1data->id())==24&&k2data->id()==23) {
	// The off-shell s-channel boson current
	VectorWaveFunction k1_k2 =
	WWWvertex_->evaluate(scale(),3,k1data->CC(),v2[k2hel],v1[k1hel]);
	// q+qb->g+v1->g+v1+v2, q+qb->v1+g->v1+v2+g
	diagrams.push_back(ffv1->evaluate(scale(),qbout[khel],p1_p2,k1_k2));
	diagrams.push_back(ffv1->evaluate(scale(),p1_k,qbin[p2hel],k1_k2));
	}
	// If W+W- calculate the four V+jet-like s-channel diagrams
	if((k1data->id()==24&&k2data->id()==-24)&&(p2data->id()==kdata->id())) {
	// The off-shell s-channel boson current
	VectorWaveFunction k1_k2;
	// q+qb->g+Z0->g+v1+v2,q+qb->Z0+g->v1+v2+g,
	tcPDPtr Z0 = getParticleData(ParticleID::Z0);
	k1_k2 = WWWvertex_->evaluate(scale(),3,Z0,v2[k2hel],v1[k1hel]);
	diagrams.push_back(FFZvertex_->evaluate(scale(),qbout[khel],p1_p2,k1_k2));
	diagrams.push_back(FFZvertex_->evaluate(scale(),p1_k,qbin[p2hel],k1_k2));
	// q+qb->g+gamma->g+v1+v2,q+qb->gamma+g->v1+v2+g,
	tcPDPtr gamma = getParticleData(ParticleID::gamma);
	k1_k2 = WWWvertex_->evaluate(scale(),3,gamma,v2[k2hel],v1[k1hel]);
	diagrams.push_back(FFPvertex_->evaluate(scale(),qbout[khel],p1_p2,k1_k2));
	diagrams.push_back(FFPvertex_->evaluate(scale(),p1_k,qbin[p2hel],k1_k2));
	}
	// Add up all diagrams to get the total amplitude:
	Complex hel_amp(0.);
	for(unsigned int ix=0;ix<diagrams.size();ix++) hel_amp += diagrams[ix];
	// If we need to fill the production ME we do it here:
	// if(getMatrix) {
	// if(p1hel==0)
	// gqb_hel_amps_(0,p2hel,k1hel,k2hel,khel) = hel_amp;
	// else
	// gqb_hel_amps_(2,p2hel,k1hel,k2hel,khel) = hel_amp;
	// }
	sum_hel_amps_sqr += norm(hel_amp);
	}
	}
	}
	}
	}

	// Fill up the remaining bits of the production ME, corresponding
	// to longitudinal gluon polarization, with (0.,0.).
	// if(getMatrix) {
	// for(unsigned int p2hel=0;p2hel<2;++p2hel) {
	// for(unsigned int k1hel=0;k1hel<3;++k1hel) {
	// for(unsigned int k2hel=0;k2hel<3;++k2hel) {
	// for(unsigned int khel=0;khel<2;++khel) {
	// gqb_hel_amps_(1,p2hel,k1hel,k2hel,khel) = Complex(0.,0.);
	// }
	// }
	// }
	// }
	// }

	// Spin and colour averaging factors = 1/4 * TR * 1/3 = 1/24
	sum_hel_amps_sqr /= 24.;

	// Symmetry factor for identical Z bosons in the final state
	if(k1data->id()==23&&k2data->id()==23) sum_hel_amps_sqr /= 2.;

	return sum_hel_amps_sqrR.tkr()R.ukr()*UnitRemoval::InvE2;
	}

	double MEPP2VVPowheg::lo_me() const {
	using namespace ThePEG::Helicity;

	double sum_hel_amps_sqr(0.);

	tcPDPtr p1data(quark_);
	tcPDPtr p2data(antiquark_);
	tcPDPtr k1data(mePartonData()[2]);
	tcPDPtr k2data(mePartonData()[3]);
	if(k1data->id()==-24&&k2data->id()==24) swap(k1data,k2data); // Should never actually occur.

	SpinorWaveFunction qSpinor(B_.p1b(),p1data,incoming);
	SpinorBarWaveFunction qbSpinor(B_.p2b(),p2data,incoming);
	vector<SpinorWaveFunction> q;
	vector<SpinorBarWaveFunction> qb;
	for(unsigned int ix=0;ix<2;ix++) {
	qSpinor.reset(ix);
	qbSpinor.reset(ix);
	q.push_back(qSpinor);
	qb.push_back(qbSpinor);
	}

	VectorWaveFunction v1Polarization(B_.k1b(),k1data,outgoing);
	VectorWaveFunction v2Polarization(B_.k2b(),k2data,outgoing);
	vector<VectorWaveFunction> v1;
	vector<VectorWaveFunction> v2;
	for(unsigned int ix=0;ix<3;ix++) {
	v1Polarization.reset(ix);
	v2Polarization.reset(ix);
	v1.push_back(v1Polarization);
	v2.push_back(v2Polarization);
	}

	AbstractFFVVertexPtr ffv1 = k1data->id()==23 ? FFZvertex_ : FFWvertex_;
	AbstractFFVVertexPtr ffv2 = k2data->id()==23 ? FFZvertex_ : FFWvertex_;

	// Collecting information for intermediate fermions
	vector<tcPDPtr> tc;
	if(abs(k1data->id())==24&&abs(k2data->id())==24) {
	if(abs(p1data->id())%2==0)
	for(int ix=0;ix<3;++ix) tc.push_back(getParticleData(1+2*ix));
	else
	for(int ix=0;ix<3;++ix) tc.push_back(getParticleData(2+2*ix));
	}
	else if(k1data->id()==23&&k2data->id()==23) tc.push_back(p1data);
	else if(abs(k1data->id())==24&&k2data->id()==23) tc.push_back(p2data);

	// Loop over helicities summing the relevant diagrams
	for(unsigned int p1hel=0;p1hel<2;++p1hel) {
	for(unsigned int p2hel=0;p2hel<2;++p2hel) {
	if((p1hel==p2hel)&&helicityConservation_) continue;
	for(unsigned int k1hel=0;k1hel<3;++k1hel) {
	for(unsigned int k2hel=0;k2hel<3;++k2hel) {
	vector<Complex> diagrams;
	// Get all t-channel diagram contributions
	tcPDPtr intermediate_t;
	for(unsigned int ix=0;ix<tc.size();ix++) {
	intermediate_t = (!(k1data->id()==24&&k2data->id()==-24)) ? p2data : tc[ix];
	SpinorWaveFunction p1_v1 = ffv1->evaluate(scale(),5,intermediate_t,q[p1hel],v1[k1hel]);
	// First calculate all the off-shell fermion currents
	// Now calculate the 6 t-channel diagrams
	// q+qb->v1+v2
	if(!((k1data->id()==24&&k2data->id()==-24)&&(abs(p1data->id())%2==1)))
	diagrams.push_back(ffv2->evaluate(scale(),p1_v1,qb[p2hel],v2[k2hel]));
	intermediate_t = (!(k1data->id()==24&&k2data->id()==-24)) ? p1data : tc[ix];
	SpinorWaveFunction p1_v2 = ffv2->evaluate(scale(),5,intermediate_t,q[p1hel],v2[k2hel]);
	// q+qb->v2+v1
	if(!((k1data->id()==24&&k2data->id()==-24)&&(abs(p1data->id())%2==0)))
	diagrams.push_back(ffv1->evaluate(scale(),p1_v2,qb[p2hel],v1[k1hel]));
	}
	// If W+Z / W-Z calculate the two V+jet-like s-channel diagrams
	if(abs(k1data->id())==24&&k2data->id()==23) {
	// The off-shell s-channel boson current
	VectorWaveFunction k1_k2 =
	WWWvertex_->evaluate(scale(),3,k1data->CC(),v2[k2hel],v1[k1hel]);
	// q+qb->v1*->v1+v2
	diagrams.push_back(ffv1->evaluate(scale(),q[p1hel],qb[p2hel],k1_k2));
	}
	// If W+W- calculate the four V+jet-like s-channel diagrams
	if((k1data->id()==24&&k2data->id()==-24)&&(p1data->id()==-p2data->id())) {
	// The off-shell s-channel boson current
	VectorWaveFunction k1_k2;
	// q+qb->Z0*->v1+v2
	tcPDPtr Z0 = getParticleData(ParticleID::Z0);
	k1_k2 = WWWvertex_->evaluate(scale(),3,Z0,v2[k2hel],v1[k1hel]);
	diagrams.push_back(FFZvertex_->evaluate(scale(),q[p1hel],qb[p2hel],k1_k2));
	// q+qb->gamma*->v1+v2
	tcPDPtr gamma = getParticleData(ParticleID::gamma);
	k1_k2 = WWWvertex_->evaluate(scale(),3,gamma,v2[k2hel],v1[k1hel]);
	diagrams.push_back(FFPvertex_->evaluate(scale(),q[p1hel],qb[p2hel],k1_k2));
	}
	// Add up all diagrams to get the total amplitude:
	Complex hel_amp(0.);
	for(unsigned int ix=0;ix<diagrams.size();ix++) hel_amp += diagrams[ix];
	// If we need to fill the production ME we do it here:
	// if(getMatrix) lo_hel_amps_(p1hel,p2hel,k1hel,k2hel) = hel_amp;
	sum_hel_amps_sqr += norm(hel_amp);
	}
	}
	}
	}

	// Spin and colour averaging factors = 1/4 * 1/3 = 1/12
	sum_hel_amps_sqr /= 12.;

	// Symmetry factor for identical Z bosons in the final state
	if(k1data->id()==23&&k2data->id()==23) sum_hel_amps_sqr /= 2.;

	return sum_hel_amps_sqr;
	}

	HardTreePtr MEPP2VVPowheg::generateHardest(ShowerTreePtr tree) {
	// Now we want to set these data vectors according to the particles we've
	// received from the current 2->2 hard collision:
	vector<ShowerProgenitorPtr> particlesToShower;
	for(map<ShowerProgenitorPtr,ShowerParticlePtr>::const_iterator
	cit=tree->incomingLines().begin();cit!=tree->incomingLines().end();++cit )
	particlesToShower.push_back(cit->first);

	qProgenitor_ = particlesToShower[0];
	qbProgenitor_ = particlesToShower[1];
	showerQuark_ = particlesToShower[0]->progenitor();
	showerAntiquark_ = particlesToShower[1]->progenitor();
	qHadron_ = particlesToShower[0]->beam();
	qbHadron_ = particlesToShower[1]->beam();

	if(showerQuark_->id()<0) {
	swap(qProgenitor_,qbProgenitor_);
	swap(showerQuark_,showerAntiquark_);
	swap(qHadron_,qbHadron_);
	}

	// In _our_ calculation we basically define the +z axis as being given
	// by the direction of the incoming quark for q+qb & q+g processes and
	// the incoming gluon for g+qbar processes. So now we might need to flip
	// the beams, bjorken x values, colliding partons accordingly:
	flipped_ = showerQuark_->momentum().z()<ZERO ? true : false;

	assert(tree->outgoingLines().size()==2);
	for(map<ShowerProgenitorPtr,tShowerParticlePtr>::const_iterator
	cit=tree->outgoingLines().begin();cit!=tree->outgoingLines().end();++cit )
	particlesToShower.push_back(cit->first);

	V1_ = particlesToShower[2]->progenitor();
	V2_ = particlesToShower[3]->progenitor();
	gluon_ = getParticleData(ParticleID::g)->produceParticle();

	// Abort the run if V1_ and V2_ are not just pointers to different gauge bosons
	if(!V1_\|\|!V2_)
	throw Exception()
	<< "MEPP2VVPowheg::generateHardest()\n"
	<< "one or both of the gauge boson pointers is null." << Exception::abortnow;
	if(!(abs(V1_->id())==24\|\|V1_->id()==23)\|\|!(abs(V2_->id())==24\|\|V2_->id()==23))
	throw Exception()
	<< "MEPP2VVPowheg::generateHardest()\nmisidentified gauge bosons"
	<< "V1_ = " << V1_->PDGName() << "\n"
	<< "V2_ = " << V2_->PDGName() << "\n"
	<< Exception::abortnow;

	// Order the gauge bosons in the same way as in the NLO calculation
	// (the same way as in the NLO matrix element):
	// W+(->e+,nu_e) W-(->e-,nu_ebar) (MCFM: 61 [nproc])
	if(V1_->id()==-24&&V2_->id()== 24) swap(V1_,V2_);
	// W+/-(mu+,nu_mu / mu-,nu_mubar) Z(nu_e,nu_ebar) (MCFM: 72+77 [nproc])
	if(V1_->id()== 23&&abs(V2_->id())== 24) swap(V1_,V2_);
	// * N.B. *
	// We should not have to do a swap in the ZZ case, even if the different
	// (off-shell) masses of the Z's are taken into account by generating
	// the Born variables using the WZ LO/NLO matrix element(s), because
	// those transformed matrix elements are, according to mathematica,
	// symmetric in the momenta (and therefore also the masses) of the 2 Z's.

	// If the vector bosons have decayed already then we may want to
	// to get the children_ (and any associated photons) to correct
	// spin correlations:
	StepPtr theSubProcess = generator()->eventHandler()->currentStep();
	tPVector outgoing = theSubProcess->getFinalState();
	children_.clear();
	photons_.clear();
	if(outgoing.size()>=4) {
	for(unsigned int ix=0;ix<outgoing.size();ix++)
	if(outgoing[ix]->parents()[0]&&
	(abs(outgoing[ix]->parents()[0]->id())==24\|\|
	abs(outgoing[ix]->parents()[0]->id())==23)) {
	if(outgoing[ix]->id()!=ParticleID::gamma)
	children_.push_back(outgoing[ix]);
	else
	photons_.push_back(outgoing[ix]);
	}
	assert(children_.size()==4);
	if(children_[0]->parents()[0]!=children_[1]->parents()[0])
	swap(children_[0],children_[2]);
	if(children_[0]->parents()[0]!=children_[1]->parents()[0])
	swap(children_[0],children_[3]);
	if(children_[0]->parents()[0]->id()!=V1_->id()) {
	swap(children_[0],children_[2]);
	swap(children_[1],children_[3]);
	}
	if(children_[0]->id()<0) swap(children_[0],children_[1]);
	if(children_[2]->id()<0) swap(children_[2],children_[3]);
	assert(children_[0]->parents()[0]==children_[1]->parents()[0]);
	assert(children_[2]->parents()[0]==children_[3]->parents()[0]);
	}

	// Now we want to construct a bornVVKinematics object. The
	// constructor for that needs all 4 momenta, q, qbar, V1_, V2_
	// in that order, as well as the Bjorken xq and xqbar.

	// Get the momenta first:
	vector<Lorentz5Momentum> theBornMomenta;
	theBornMomenta.push_back(showerQuark_->momentum());
	theBornMomenta.push_back(showerAntiquark_->momentum());
	theBornMomenta.push_back(V1_->momentum());
	theBornMomenta.push_back(V2_->momentum());
	// N.B. if the showerQuark_ travels in the -z direction the born kinematics object
	// will detect this and rotate all particles by pi about the y axis!

	// Leading order momentum fractions:
	tcPPtr qHadron = generator()->currentEvent()->primaryCollision()->incoming().first;
	tcPPtr qbHadron = generator()->currentEvent()->primaryCollision()->incoming().second;
	assert(qHadron->children().size()>0&&qbHadron->children().size()>0);
	if(qHadron->children()[0]->id()<0) swap(qHadron,qbHadron);

	// quark and antiquark momentum fractions respectively
	double xa = showerQuark_ ->momentum().z()/qHadron ->momentum().z();
	double xb = showerAntiquark_->momentum().z()/qbHadron->momentum().z();

	// Create the object containing all 2->2 __kinematic__ information:
	B_ = bornVVKinematics(theBornMomenta,xa,xb);

	// lo_me_ is the colour & spin averaged n-body matrix element squared:
	lo_me_ = lo_me(true);

	// Attempt to generate some radiative variables and their kinematics:
	vector<Lorentz5Momentum> theRealMomenta;
	channel_ = 999;
	if(!getEvent(theRealMomenta,channel_)) return HardTreePtr();

	// Set the maximum pT for subsequent emissions:
	pT_ < min_pT_ ? qProgenitor_ ->maximumpT(min_pT_) : qProgenitor_ ->maximumpT(pT_);
	pT_ < min_pT_ ? qbProgenitor_->maximumpT(min_pT_) : qbProgenitor_->maximumpT(pT_);

	// Determine whether the quark or antiquark emitted:
	fermionNumberOfMother_=0;
	if((channel_==0&&theRealMomenta[0].z()/theRealMomenta[4].z()>=ZERO)\|\|
	channel_==2) fermionNumberOfMother_ = 1;
	else if((channel_==0&&theRealMomenta[0].z()/theRealMomenta[4].z()<ZERO)\|\|
	channel_==1) fermionNumberOfMother_ = -1;
	assert(fermionNumberOfMother_!=0);

	// If the quark in the original tree was travelling in the -z direction
	// then we need to unflip the event (flips are automatically carried out
	// when the original quark travels in the in -z direction when the
	// bornVVKinematics object is created):
	if(flipped_)
	for(unsigned int ix=0;ix<theRealMomenta.size();ix++)
	theRealMomenta[ix].rotateY(-Constants::pi);

	// Randomly rotate the event about the beam axis:
	double randomPhi(UseRandom::rnd()2.Constants::pi);
	for(unsigned int ix=0;ix<theRealMomenta.size();ix++)
	theRealMomenta[ix].rotateZ(randomPhi);

	// Warn if momentum conservation is not obeyed:
	Lorentz5Momentum inMinusOut(theRealMomenta[0]+theRealMomenta[1]
	-theRealMomenta[2]-theRealMomenta[3]
	-theRealMomenta[4]);
	if(inMinusOut.t()>0.1GeV\|\|inMinusOut.x()>0.1GeV\|\|
	inMinusOut.y()>0.1GeV\|\|inMinusOut.z()>0.1GeV)
	cout << "MEPP2VVPowheg::generateHardest\n"
	<< "Momentum imbalance in V1 V2 rest frame\n"
	<< "P_in minus P_out = " << inMinusOut/GeV << endl;

	// From the radiative kinematics we now have to form ShowerParticle objects:
	ShowerParticlePtr p1;
	ShowerParticlePtr p2;
	ShowerParticlePtr k1(new_ptr(ShowerParticle(V1_->dataPtr(),true )));
	ShowerParticlePtr k2(new_ptr(ShowerParticle(V2_->dataPtr(),true )));
	ShowerParticlePtr k ;
	// q+qbar -> V1+V2+g
	if(channel_==0) {
	p1 = new_ptr(ShowerParticle(showerQuark_->dataPtr() ,false));
	p2 = new_ptr(ShowerParticle(showerAntiquark_->dataPtr() ,false));
	k = new_ptr(ShowerParticle(gluon_->dataPtr() ,true ));
	}
	// q+g -> V1+V2+q
	else if(channel_==1) {
	p1 = new_ptr(ShowerParticle(showerQuark_->dataPtr() ,false));
	p2 = new_ptr(ShowerParticle(gluon_->dataPtr() ,false));
	k = new_ptr(ShowerParticle(showerAntiquark_->dataPtr()->CC() ,true ));
	}
	// g+qbar -> V1+V2+qbar
	else {
	p1 = new_ptr(ShowerParticle(gluon_->dataPtr() ,false));
	p2 = new_ptr(ShowerParticle(showerAntiquark_->dataPtr() ,false));
	k = new_ptr(ShowerParticle(showerQuark_->dataPtr()->CC() ,true ));
	}
	// Set the momenta of the ShowerParticlePtr's:
	p1->set5Momentum(theRealMomenta[0]);
	p2->set5Momentum(theRealMomenta[1]);
	k1->set5Momentum(theRealMomenta[2]);
	k2->set5Momentum(theRealMomenta[3]);
	k ->set5Momentum(theRealMomenta[4]);
	// Then construct another set of ShowerPointers that will be
	// useful in creating the hardTree, using this information:
	ShowerParticlePtr mother;
	ShowerParticlePtr spacelikeSon;
	ShowerParticlePtr timelikeSon;
	ShowerParticlePtr spectator;
	if(fermionNumberOfMother_==1) {
	mother = new_ptr(ShowerParticle(showerQuark_->dataPtr() ,false));
	spacelikeSon = p1;
	timelikeSon = k;
	spectator = p2;
	} else if(fermionNumberOfMother_==-1) {
	mother = new_ptr(ShowerParticle(showerAntiquark_->dataPtr(),false));
	spacelikeSon = p2;
	timelikeSon = k;
	spectator = p1;
	} else {
	throw Exception() << "MEPP2VVPowheg::generateHardest()"
	<< "Failed to determine whether the q or qbar branched"
	<< Exception::runerror;
	}
	Lorentz5Momentum motherMomentum(spacelikeSon->momentum()-timelikeSon->momentum());
	motherMomentum.rescaleMass();
	mother->set5Momentum(motherMomentum);
	// Create HardBranchingPtrs for the particles
	HardBranchingPtr spacelikeSonBranching =
	new_ptr(HardBranching(spacelikeSon,SudakovPtr(),HardBranchingPtr() ,HardBranching::Incoming ));
	HardBranchingPtr timelikeSonBranching =
	new_ptr(HardBranching(timelikeSon ,SudakovPtr(),spacelikeSonBranching,HardBranching::Outgoing));
	HardBranchingPtr spectatorBranching =
	new_ptr(HardBranching(spectator ,SudakovPtr(),HardBranchingPtr() ,HardBranching::Incoming ));
	HardBranchingPtr motherBranching =
	new_ptr(HardBranching(mother ,SudakovPtr(),spacelikeSonBranching,HardBranching::Incoming ));
	HardBranchingPtr V1_Branching =
	new_ptr(HardBranching(k1 ,SudakovPtr(),HardBranchingPtr() ,HardBranching::Outgoing));
	HardBranchingPtr V2_Branching =
	new_ptr(HardBranching(k2 ,SudakovPtr(),HardBranchingPtr() ,HardBranching::Outgoing));

	// N.B. The DrellYanHardGenerator first adds the timelikeSonBranching as a child
	// child of the spacelikeSonBranching before adding the motherBranching. We do
	// it the other way round in accordance with PowhegEvolver::checkShowerMomentum.
	spacelikeSonBranching->addChild(motherBranching);
	spacelikeSonBranching->addChild(timelikeSonBranching);
	motherBranching->colourPartner(spectatorBranching);
	spectatorBranching->colourPartner(motherBranching);

	vector<HardBranchingPtr> spacelikeBranchings,hardBranchings;
	spacelikeBranchings.push_back(fermionNumberOfMother_ == 1 ?
	spacelikeSonBranching : spectatorBranching);
	spacelikeBranchings.push_back(fermionNumberOfMother_ == -1 ?
	spacelikeSonBranching : spectatorBranching);
	hardBranchings.push_back(motherBranching);
	hardBranchings.push_back(spectatorBranching);
	hardBranchings.push_back(V1_Branching);
	hardBranchings.push_back(V2_Branching);

	// Recalculate the hard vertex for this event:
	// For spin correlations, if an emission occurs go calculate the relevant
	// combination of amplitudes for the ProductionMatrixElement.
	if(realMESpinCorrelations_) {
	// Here we reset the realVVKinematics n+1 momenta to be those
	// of the lab frame in order to calculate the spin correlations.
	// Note that these momenta are not used for anything else after
	// this.
	R_.p1r(theRealMomenta[0]);
	R_.p2r(theRealMomenta[1]);
	R_.k1r(theRealMomenta[2]);
	R_.k2r(theRealMomenta[3]);
	R_.kr (theRealMomenta[4]);
	if(channel_==0) t_u_M_R_qqb_hel_amp(R_,true);
	else if(channel_==1) t_u_M_R_qg_hel_amp (R_,true);
	else if(channel_==2) t_u_M_R_gqb_hel_amp(R_,true);
	recalculateVertex();
	}
	// Construct the HardTree object needed to perform the showers
	HardTreePtr hardTree=new_ptr(HardTree(hardBranchings,spacelikeBranchings,
	ShowerInteraction::QCD));

	if(hardTree->branchings().size()!=4) throw Exception()
	<< "MEPP2VVPowheg::generateHardest()\n"
	<< "The hardTree has " << hardTree->branchings().size() << "branchings\n"
	<< hardTree << "\n" << Exception::runerror;
	if((motherBranching->parent()!=spacelikeSonBranching)&&
	spacelikeSonBranching->parent()!=HardBranchingPtr()&&
	spectatorBranching->parent()!=HardBranchingPtr()) throw Exception()
	<< "MEPP2VVPowheg::generateHardest()\n"
	<< "The parent-child relationships are not valid.\n"
	<< "motherBranching->parent() = " << motherBranching->parent() << "\n"
	<< "spacelikeSonBranching = " << spacelikeSonBranching << "\n"
	<< "spectatorBranching->parent() = " << spectatorBranching->parent() << "\n"
	<< "spacelikeSonBranching->parent() = " << spacelikeSonBranching->parent() << "\n"
	<< Exception::runerror;

	if(fermionNumberOfMother_== 1) {
	hardTree->connect(showerQuark_ ,motherBranching );
	hardTree->connect(showerAntiquark_,spectatorBranching);
	spacelikeSonBranching->beam(qProgenitor_ ->original()->parents()[0]);
	motherBranching ->beam(qProgenitor_ ->original()->parents()[0]);
	spectatorBranching ->beam(qbProgenitor_->original()->parents()[0]);
	} else if(fermionNumberOfMother_==-1) {
	hardTree->connect(showerAntiquark_,motherBranching );
	hardTree->connect(showerQuark_ ,spectatorBranching);
	spacelikeSonBranching->beam(qbProgenitor_->original()->parents()[0]);
	motherBranching ->beam(qbProgenitor_->original()->parents()[0]);
	spectatorBranching ->beam(qProgenitor_ ->original()->parents()[0]);
	}
	// hardTree->connect(V1_ ,V1_Branching );
	// hardTree->connect(V2_ ,V2_Branching );

	// This if {...} else if {...} puts the mother and spectator on the same colour
	// line. If we don't do this, then when reconstructFinalStateShower calls
	// setInitialEvolutionScales it says it failed to set the colour partners, so
	// it can't set the scale and it just forgets the emission / event. This seems
	// like an unintrusive work-around until reconstructFinalStateShower is sorted.
	ColinePtr bornColourLine=new_ptr(ColourLine());
	if(fermionNumberOfMother_== 1) {
	bornColourLine->addColoured(mother);
	bornColourLine->addAntiColoured(spectator);
	} else if(fermionNumberOfMother_==-1) {
	bornColourLine->addAntiColoured(mother);
	bornColourLine->addColoured(spectator);
	}
	// this is a pain but we need the boost, which we don't have yet here!!
	vector<Lorentz5Momentum> pin(2);
	vector<Lorentz5Momentum> pq (2);
	vector<HardBranchingPtr>::iterator cit;
	pin[0] = motherBranching ->branchingParticle()->momentum();
	pin[1] = spectatorBranching->branchingParticle()->momentum();
	Energy etemp = motherBranching ->beam()->momentum().z();
	pq[0] = Lorentz5Momentum(ZERO, ZERO,etemp, abs(etemp));
	etemp = spectatorBranching->beam()->momentum().z();
	pq[1] = Lorentz5Momentum(ZERO, ZERO,etemp, abs(etemp));
	// decompose the momenta
	double alpha[2],beta[2];
	Energy2 p12=pq[0]*pq[1];
	Lorentz5Momentum pt[2];
	for(unsigned int ix=0;ix<2;++ix) {
	alpha[ix] = pin[ix]*pq[1]/p12;
	beta [ix] = pin[ix]*pq[0]/p12;
	pt[ix] = pin[ix]-alpha[ix]pq[0]-beta[ix]pq[1];
	}
	// parton level centre-of-mass
	Lorentz5Momentum pcm=pin[0]+pin[1];
	pcm.rescaleMass();
	double rap=pcm.rapidity();
	// hadron level cmf
	Energy2 s = (pq[0] +pq[1] ).m2();
	// calculate the x values
	double x[2]={sqrt(pcm.mass2()/sexp(2.rap)),pcm.mass2()/s/x[0]};
	if(pq[0].z()<ZERO) swap(x[0],x[1]);
	Lorentz5Momentum pnew = x[0]pq[0]+x[1]pq[1];
	LorentzRotation toRest = LorentzRotation(-pcm .boostVector());
	LorentzRotation fromRest = LorentzRotation( pnew.boostVector());
	Lorentz5Momentum pv[2]=
	{fromResttoRestV1_Branching->branchingParticle()->momentum(),
	fromResttoRestV2_Branching->branchingParticle()->momentum()};
	LorentzRotation R(-(mother->momentum()+spectator ->momentum()).boostVector());
	R.boost((showerQuark_->momentum()+showerAntiquark_->momentum()).boostVector());
	for(map<tShowerTreePtr,pair<tShowerProgenitorPtr,tShowerParticlePtr> >::const_iterator
	tit = tree->treelinks().begin();
	tit != tree->treelinks().end();++tit) {
	ShowerTreePtr decayTree = tit->first;
	map<ShowerProgenitorPtr,ShowerParticlePtr>::const_iterator
	cit = decayTree->incomingLines().begin();
	// reset the momentum of the decay particle
	Lorentz5Momentum oldMomentum = cit->first->progenitor()->momentum();
	Lorentz5Momentum newMomentum = tit->second.second == V1_ ? pv[0] : pv[1];
	map<ShowerProgenitorPtr,tShowerParticlePtr>::const_iterator cjt;
	// reset the momenta of the decay products,
	LorentzRotation boostToORF(newMomentum.findBoostToCM(),
	newMomentum.e()/newMomentum.mass());
	tPPtr children[2];
	if(children_[0]->parents()[0]==cit->first->original()) {
	children[0] = children_[0];
	children[1] = children_[1];
	}
	else {
	children[0] = children_[2];
	children[1] = children_[3];
	}
	if(UseRandom::rndbool()) swap(children[0],children[1]);
	double originalTheta0 = (boostToORFRchildren[0]->momentum()).theta();
	double originalPhi0 = (boostToORFRchildren[0]->momentum()).phi();
	boostToORF.rotateZ(-originalPhi0);
	boostToORF.rotateY(-originalTheta0);
	double originalPhi1 = (boostToORF*children[1]->momentum()).phi();
	LorentzRotation boost(oldMomentum.findBoostToCM(),oldMomentum.e()/oldMomentum.mass());
	tPPtr newChildren[2];
	for(cjt=decayTree->outgoingLines().begin();
	cjt!=decayTree->outgoingLines().end();++cjt) {
	if(cjt->first->progenitor()->id()==children[0]->id())
	newChildren[0] = cjt->first->progenitor();
	else if(cjt->first->progenitor()->id()==children[1]->id())
	newChildren[1] = cjt->first->progenitor();
	}
	boost.rotateZ(-(boost*newChildren[0]->momentum()).phi());
	boost.rotateY(-(boost*newChildren[0]->momentum()).theta());
	boost.rotateZ(-(boost*newChildren[1]->momentum()).phi());
	boost.rotateZ( originalPhi1);
	boost.rotateY( originalTheta0);
	boost.rotateZ( originalPhi0);
	boost.boost(-oldMomentum.findBoostToCM(),
	oldMomentum.e()/oldMomentum.mass());
	for(cjt=decayTree->outgoingLines().begin();
	cjt!=decayTree->outgoingLines().end();++cjt) {
	Lorentz5Momentum ptemp = boost*cjt->first->progenitor()->momentum();
	cjt->first->original() ->set5Momentum(cjt->first->progenitor()->momentum());
	cjt->first->progenitor()->deepTransform(boost);
	cjt->first->original() ->deepTransform(boost);
	cjt->first->copy() ->deepTransform(boost);
	}
	}
	return hardTree;
	}

	double MEPP2VVPowheg::getResult(int channel, realVVKinematics R, Energy pT) {

	// This routine should return the integrand of the exact Sudakov form factor,
	// defined precisely as
	// KH 19th August - next 2 lines changed for phi in 0->pi not 0->2pi
	// \Delta(pT) = exp[ - \int_{pT}^{pTmax} dpT dYk d\phi/pi * getResult(...) ]
	// (Where phi is in 0->pi NOT 0->2*pi !)

	// Get pi for the prefactor:
	using Constants::pi;

	// Get the VV invariant mass^2:
	Energy2 p2 = B_.sb();

	// Get the momentum fractions for the n+1 body event:
	double x1 = R.x1r();
	double x2 = R.x2r();

	// Reject the event if the x1 and x2 values are outside the phase space:
	if(x1<0.\|\|x1>1.\|\|x2<0.\|\|x2>1.\|\|x1*x2<p2/sqr(generator()->maximumCMEnergy())) return 0.;

	// Get the momentum fractions for the n body event:
	double x1b = B_.x1b();
	double x2b = B_.x2b();

	// Get the mandelstam variables needed to calculate the n+1 body matrix element:
	Energy2 s = R.sr() ;
	Energy2 t_u_MR_o_MB;
	double lo_lumi, nlo_lumi;

	// The luminosity function for the leading order n-body process:
	lo_lumi = qHadron_ ->pdf()->xfx(qHadron_ ,showerQuark_ ->dataPtr(),PDFScale_,x1b)*
	qbHadron_->pdf()->xfx(qbHadron_,showerAntiquark_->dataPtr(),PDFScale_,x2b);

	// Now we calculate the luminosity functions (product of the two pdfs) for the
	// real emission process(es) and also their matrix elements:
	// q + qbar -> V + V + g
	if(channel==0) {
	nlo_lumi = qHadron_ ->pdf()->xfx(qHadron_ ,showerQuark_ ->dataPtr() ,PDFScale_,x1)
	* qbHadron_->pdf()->xfx(qbHadron_,showerAntiquark_->dataPtr() ,PDFScale_,x2);
	t_u_MR_o_MB = t_u_M_R_qqb_hel_amp(R,false)/lo_me_;
	}
	// q + g -> V + V + q
	else if(channel==1) {
	nlo_lumi = qHadron_ ->pdf()->xfx(qHadron_ ,showerQuark_->dataPtr() ,PDFScale_,x1)
	* qbHadron_->pdf()->xfx(qbHadron_,getParticleData(ParticleID::g),PDFScale_,x2);
	t_u_MR_o_MB = t_u_M_R_qg_hel_amp(R,false)/lo_me_;
	}
	// g + qbar -> V + V + qbar
	else {
	nlo_lumi = qHadron_ ->pdf()->xfx(qHadron_ ,getParticleData(ParticleID::g),PDFScale_,x1)
	* qbHadron_->pdf()->xfx(qbHadron_,showerAntiquark_->dataPtr() ,PDFScale_,x2);
	t_u_MR_o_MB = t_u_M_R_gqb_hel_amp(R,false)/lo_me_;
	}

	// Multiply ratio of the real emission matrix elements to the Born matrix element
	// by the ratio of the pdfs for the real emission and born processes to get theWeight
	if(lo_lumi<=0.\|\|nlo_lumi<=0.)
	return 0.;
	else
	return t_u_MR_o_MB * ( nlo_lumi/lo_lumi * p2/s )
	* sqr(p2/s)/8./pi/pi
	/ pT / p2
	* GeV;
	}

	bool MEPP2VVPowheg::getEvent(vector<Lorentz5Momentum> & theRealMomenta,
	unsigned int & channel) {
	// Invariant mass of the colliding hadrons:
	Energy2 S = sqr(generator()->maximumCMEnergy());

	// Born variables which are preserved (mass and rapidity of the diboson system):
	Energy2 p2 = B_.sb();
	double Yb = B_.Yb();

	// Born variables which are not preserved but are needed (the momentum fractions):
	double x1b(B_.x1b()), x2b(B_.x2b());
	double x12b(x1bx1b), x22b(x2bx2b);

	// Maximum jet pT (half of the hadronic C.O.M. energy. N.B. this is overestimated a lot):
	Energy starting_pT = sqrt(S)/2.;

	// Initialize the pT_ integration limit i.e. the pT of the generated emission:
	pT_ = ZERO;

	// The pT integration variable:
	Energy pT;

	// The x_1 & x_2 momentum fractions corresponding to incoming momenta p1 & p2:
	double x1_(-999.), x2_(-999.);
	double x1 (-999.), x2 (-999.);

	// The jet rapidity integration variable and its limits:
	double Yk, minYk(-8.0), maxYk(8.0);

	// The theta2 integration variable (the azimuthal angle of the gluon w.r.t
	// V1 in the V1 & V2 rest frame:
	double theta2;

	// The realVVKinematics object corresponding to the current integration
	// set of integration variables:
	realVVKinematics R;

	// The veto algorithm rejection weight and a corresponding flag:
	double rejectionWeight;
	bool rejectEmission ;

	// Initialize the flag indicating the selected radiation channel:
	channel=999;

	// Some product of constants used for the crude distribution:
	double a(0.);

	for(int j=0;j<3;j++) {
	pT=starting_pT;
	a =(maxYk-minYk)*prefactor_[j]/2./b0_;
	do {
	// Generate next pT according to exp[- \int^{pTold}_{pT} dpT a*(power-1)/(pT^power)]
	// pT = GeV/pow( pow(GeV/pT,power_-1.) - log(UseRandom::rnd())/a
	// , 1./(power_-1.) );
	// Generate next pT according to exp[- \int^{pTold}_{pT} dpT alpha1loop*prefactor/pT ]
	pT = LambdaQCD_exp( 0.5exp( log(log(sqr(pT/LambdaQCD_)))+log(UseRandom::rnd())/a ) );
	// Generate rapidity of the jet:
	Yk = minYk + UseRandom::rnd()*(maxYk - minYk);
	// Generate the theta2 radiative variable:
	// KH 19th August - next line changed for phi in 0->pi not 0->2pi
	// theta2 = UseRandom::rnd() * 2.*Constants::pi;
	theta2 = UseRandom::rnd() * Constants::pi;
	// eT of the diboson system:
	Energy eT = sqrt(pT*pT+p2);
	// Calculate the eT and then solve for x_{\oplus} & x_{\ominus}:
	x1 = (pTexp( Yk)+eTexp( Yb))/sqrt(S);
	x2 = (pTexp(-Yk)+eTexp(-Yb))/sqrt(S);
	// Calculate the xr radiative variable:
	double xr(p2/(x1x2S));
	// Then use this to calculate the y radiative variable:
	double y(-((xr+1.)/(xr-1.))(xrsqr(x1/x1b)-1.)/(xr*sqr(x1/x1b)+1.));
	// The y value above should equal the one commented out below this line:
	// double y( ((xr+1.)/(xr-1.))(xrsqr(x2/x2b)-1.)/(xr*sqr(x2/x2b)+1.));
	// Now we get the lower limit on the x integration, xbar:
	double omy(1.-y), opy(1.+y);
	double xbar1 = 2.opyx12b/(sqrt(sqr(1.+x12b)sqr(omy)+16.yx12b)+omy(1.-x1b)*(1.+x1b));
	double xbar2 = 2.omyx22b/(sqrt(sqr(1.+x22b)sqr(opy)-16.yx22b)+opy(1.-x2b)*(1.+x2b));
	double xbar = max(xbar1,xbar2);
	// Now we can calculate xtilde:
	double xt = (xr-xbar)/(1.-xbar);
	// Finally we can make the realVVKinematics object:
	R = realVVKinematics(B_,xt,y,theta2);
	// The next thing we have to do is set the QCD, EW and PDF scales using R:
	setTheScales(pT);
	// ... and so calculate rejection weight:
	rejectionWeight = getResult(j,R,pT);
	// If generating according to exp[- \int^{pTold}_{pT} dpT a*(power-1)/(pT^power)]
	// rejectionWeight/= showerAlphaS_->overestimateValue()prefactor_[j]pow(GeV/pT,power_);
	// If generating according to exp[- \int^{pTold}_{pT} dpT alpha1loop*prefactor/pT ]
	rejectionWeight/= 1./b0_/log(sqr(pT/LambdaQCD_))prefactor_[j]GeV/pT;
	rejectEmission = UseRandom::rnd()>rejectionWeight;
	// The event is a no-emission event if pT goes past min_pT_ - basically set to
	// outside the histogram bounds (hopefully histogram objects just ignore it then).
	if(pT<min_pT_) {
	pT=ZERO;
	rejectEmission = false;
	}
	if(rejectionWeight>1.) {
	ostringstream stream;
	stream << "MEPP2VVPowheg::getEvent weight for channel " << j
	<< " is greater than one: " << rejectionWeight << endl;
	generator()->logWarning( Exception(stream.str(), Exception::warning) );
	}
	}
	while(rejectEmission);
	// set pT of emission etc
	if(pT>pT_) {
	channel = j;
	pT_ = pT;
	Yk_ = Yk;
	R_ = R ;
	x1_ = x1;
	x2_ = x2;
	}
	}
	// Was this an (overall) no emission event?
	if(pT_<min_pT_) {
	pT_ = ZERO;
	channel = 3;
	}
	if(channel==3) return false;
	if(channel>3) throw Exception()
	<< "MEPP2VVPowheg::getEvent() channel = " << channel
	<< " pT = " << pT/GeV << " pT_ = " << pT_/GeV
	<< Exception::abortnow;

	// Work out the momenta in the lab frame, reserving the mass and rapidity
	// of the VV system:
	LorentzRotation yzRotation;
	yzRotation.setRotateX(-atan2(pT_/GeV,sqrt(p2)/GeV));
	LorentzRotation boostFrompTisZero;
	boostFrompTisZero.setBoostY(-pT_/sqrt(p2+pT_*pT_));
	LorentzRotation boostFromYisZero;
	boostFromYisZero.setBoostZ(tanh(Yb));

	theRealMomenta.resize(5);
	theRealMomenta[0] = Lorentz5Momentum(ZERO,ZERO, x1_sqrt(S)/2., x1_sqrt(S)/2.,ZERO);
	theRealMomenta[1] = Lorentz5Momentum(ZERO,ZERO,-x2_sqrt(S)/2., x2_sqrt(S)/2.,ZERO);
	theRealMomenta[2] = boostFromYisZeroboostFrompTisZeroyzRotation*(R_.k1r());
	theRealMomenta[3] = boostFromYisZeroboostFrompTisZeroyzRotation*(R_.k2r());
	theRealMomenta[4] = Lorentz5Momentum(ZERO, pT_, pT_sinh(Yk_), pT_cosh(Yk_),ZERO);

	return true;
	}


	void MEPP2VVPowheg::setTheScales(Energy pT) {
	// Work out the scales we want to use in the matrix elements and the pdfs:
	// Scale for alpha_S: pT^2 of the diboson system.
	QCDScale_ = max(pT*pT,sqr(min_pT_));
	// Scale for real emission PDF:
	// pT^2+mVV^2 - as mcfm does in the case of a single W/Z boson).
	// Energy2 PDFScale_ = max(R.pT2_in_lab(),sqr(min_pT_))+R.s2r();
	// pT^2 - as advocated by Nason & Ridolfi for ZZ production & Alioli et al for gg->h:
	PDFScale_ = max(pT*pT,sqr(min_pT_));
	// Scale of electroweak vertices: mVV^2 the invariant mass of the diboson system.
	// EWScale_ = B_.sb();
	// ... And this choice is more like what can be seen in mcatnlo_vbmain.f (weird).
	EWScale_ = 0.5*(B_.k12b()+B_.k22b());
	return;
	}

	/***************************************************************************/
	// This is identical to the code in the Powheg matrix element. It should
	// equal t_u_M_R_qqb in there, which is supposed to be the real emission ME
	// times tk*uk.
	Energy2 MEPP2VVPowheg::t_u_M_R_qqb_hel_amp(realVVKinematics R, bool getMatrix) const {
	using namespace ThePEG::Helicity;

	ProductionMatrixElement qqb_hel_amps(PDT::Spin1Half,PDT::Spin1Half,
	PDT::Spin1 ,PDT::Spin1 ,
	PDT::Spin1);

	double sum_hel_amps_sqr(0.);

	tcPDPtr p1data(showerQuark_->dataPtr());
	tcPDPtr p2data(showerAntiquark_->dataPtr());
	tcPDPtr k1data(V1_->dataPtr());
	tcPDPtr k2data(V2_->dataPtr());
	tcPDPtr kdata(getParticleData(ParticleID::g));
	if(k1data->id()==-24&&k2data->id()==24) swap(k1data,k2data);

	SpinorWaveFunction qSpinor(R.p1r(),p1data,incoming);
	SpinorBarWaveFunction qbSpinor(R.p2r(),p2data,incoming);
	vector<SpinorWaveFunction> q;
	vector<SpinorBarWaveFunction> qb;
	for(unsigned int ix=0;ix<2;ix++) {
	qSpinor.reset(ix);
	qbSpinor.reset(ix);
	q.push_back(qSpinor);
	qb.push_back(qbSpinor);
	}

	VectorWaveFunction v1Polarization(R.k1r(),k1data,outgoing);
	VectorWaveFunction v2Polarization(R.k2r(),k2data,outgoing);
	vector<VectorWaveFunction> v1;
	vector<VectorWaveFunction> v2;
	for(unsigned int ix=0;ix<3;ix++) {
	v1Polarization.reset(ix);
	v2Polarization.reset(ix);
	v1.push_back(v1Polarization);
	v2.push_back(v2Polarization);
	}

	VectorWaveFunction gPolarization(R.kr(),kdata,outgoing);
	vector<VectorWaveFunction> g;
	for(unsigned int ix=0;ix<3;ix+=2) {
	gPolarization.reset(ix);
	g.push_back(gPolarization);
	}

	AbstractFFVVertexPtr ffg = FFGvertex_;
	AbstractFFVVertexPtr ffv1 = k1data->id()==23 ? FFZvertex_ : FFWvertex_;
	AbstractFFVVertexPtr ffv2 = k2data->id()==23 ? FFZvertex_ : FFWvertex_;

	// Collecting information for intermediate fermions
	vector<tcPDPtr> tc;
	if(abs(k1data->id())==24&&abs(k2data->id())==24) {
	if(abs(p1data->id())%2==0)
	for(int ix=0;ix<3;++ix) tc.push_back(getParticleData(1+2*ix));
	else
	for(int ix=0;ix<3;++ix) tc.push_back(getParticleData(2+2*ix));
	}
	else if(k1data->id()==23&&k2data->id()==23) tc.push_back(p1data);
	else if(abs(k1data->id())==24&&k2data->id()==23) tc.push_back(p2data);

	// Loop over helicities summing the relevant diagrams
	for(unsigned int p1hel=0;p1hel<2;++p1hel) {
	for(unsigned int p2hel=0;p2hel<2;++p2hel) {
	for(unsigned int khel=0;khel<2;++khel) {
	SpinorWaveFunction p1_k = ffg->evaluate(QCDScale_,5,p1data,q[p1hel],g[khel]);
	SpinorBarWaveFunction p2_k = ffg->evaluate(QCDScale_,5,p2data,qb[p2hel],g[khel]);
	for(unsigned int k1hel=0;k1hel<3;++k1hel) {
	for(unsigned int k2hel=0;k2hel<3;++k2hel) {
	// If helicity is exactly conserved (massless quarks) skip if p1hel=p2hel
	// but if the production ME is required first fill it with (0.,0.).
	if((p1hel==p2hel)&&helicityConservation_) {
	if(getMatrix) {
	if(khel==0)
	qqb_hel_amps(p1hel,p2hel,k1hel,k2hel,0) = Complex(0.,0.);
	else
	qqb_hel_amps(p1hel,p2hel,k1hel,k2hel,2) = Complex(0.,0.);
	}
	continue;
	}
	vector<Complex> diagrams;
	// Get all t-channel diagram contributions
	tcPDPtr intermediate_t;
	for(unsigned int ix=0;ix<tc.size();ix++) {
	intermediate_t = (!(k1data->id()==24&&k2data->id()==-24)) ? p2data : tc[ix];
	// Note: choosing 5 as the second argument ffvX_->evaluate() sets
	// option 5 in thepeg/Helicity/Vertex/VertexBase.cc, which makes
	// the (fermion) propagator denominator massless: 1/p^2.
	// If W+Z / W-Z calculate the two V+jet-like s-channel diagrams
	SpinorWaveFunction p1_v1 = ffv1->evaluate(EWScale_,5,intermediate_t,q[p1hel],v1[k1hel]);
	SpinorBarWaveFunction p2_v2 = ffv2->evaluate(EWScale_,5,intermediate_t,qb[p2hel],v2[k2hel]);
	// First calculate all the off-shell fermion currents
	// Now calculate the 6 t-channel diagrams
	// q+qb->g+v1+v2, q+qb->v1+g+v2, q+qb->v1+v2+g
	if(!((k1data->id()==24&&k2data->id()==-24)&&(abs(p1data->id())%2==1))) {
	diagrams.push_back(ffv1->evaluate(EWScale_,p1_k,p2_v2,v1[k1hel]));
	diagrams.push_back(ffg->evaluate(QCDScale_,p1_v1,p2_v2,g[khel]));
	diagrams.push_back(ffv2->evaluate(EWScale_,p1_v1,p2_k,v2[k2hel]));
	}
	intermediate_t = (!(k1data->id()==24&&k2data->id()==-24)) ? p1data : tc[ix];
	SpinorWaveFunction p1_v2 = ffv2->evaluate(EWScale_,5,intermediate_t,q[p1hel],v2[k2hel]);
	SpinorBarWaveFunction p2_v1 = ffv1->evaluate(EWScale_,5,intermediate_t,qb[p2hel],v1[k1hel]);
	// q+qb->g+v2+v1, q+qb->v2+g+v1, q+qb->v2+v1+g
	if(!((k1data->id()==24&&k2data->id()==-24)&&(abs(p1data->id())%2==0))) {
	diagrams.push_back(ffv2->evaluate(EWScale_,p1_k,p2_v1,v2[k2hel]));
	diagrams.push_back(ffg->evaluate(QCDScale_,p1_v2,p2_v1,g[khel]));
	diagrams.push_back(ffv1->evaluate(EWScale_,p1_v2,p2_k,v1[k1hel]));
	}
	}
	// Note: choosing 3 as the second argument in WWWvertex_->evaluate()
	// sets option 3 in thepeg/Helicity/Vertex/VertexBase.cc , which
	// means the propagator does not contain a width factor (which is
	// good re. gauge invariance).
	// If W+Z / W-Z calculate the two V+jet-like s-channel diagrams
	if(abs(k1data->id())==24&&k2data->id()==23) {
	// The off-shell s-channel boson current
	VectorWaveFunction k1_k2 =
	WWWvertex_->evaluate(EWScale_,3,k1data->CC(),v2[k2hel],v1[k1hel]);
	// q+qb->g+v1->g+v1+v2, q+qb->v1+g->v1+v2+g
	diagrams.push_back(ffv1->evaluate(EWScale_,p1_k,qb[p2hel],k1_k2));
	diagrams.push_back(ffv1->evaluate(EWScale_,q[p1hel],p2_k,k1_k2));
	}
	// If W+W- calculate the four V+jet-like s-channel diagrams
	if((k1data->id()==24&&k2data->id()==-24)&&(p1data->id()==-p2data->id())) {
	// The off-shell s-channel boson current
	VectorWaveFunction k1_k2;
	// q+qb->g+Z0->g+v1+v2,q+qb->Z0+g->v1+v2+g,
	tcPDPtr Z0 = getParticleData(ParticleID::Z0);
	k1_k2 = WWWvertex_->evaluate(EWScale_,3,Z0,v2[k2hel],v1[k1hel]);
	diagrams.push_back(FFZvertex_->evaluate(EWScale_,p1_k,qb[p2hel],k1_k2));
	diagrams.push_back(FFZvertex_->evaluate(EWScale_,q[p1hel],p2_k,k1_k2));
	// q+qb->g+gamma->g+v1+v2,q+qb->gamma+g->v1+v2+g,
	tcPDPtr gamma = getParticleData(ParticleID::gamma);
	k1_k2 = WWWvertex_->evaluate(EWScale_,3,gamma,v2[k2hel],v1[k1hel]);
	diagrams.push_back(FFPvertex_->evaluate(EWScale_,p1_k,qb[p2hel],k1_k2));
	diagrams.push_back(FFPvertex_->evaluate(EWScale_,q[p1hel],p2_k,k1_k2));
	}
	// Add up all diagrams to get the total amplitude:
	Complex hel_amp(0.);
	for(unsigned int ix=0;ix<diagrams.size();ix++) hel_amp += diagrams[ix];
	// If we need to fill the production ME we do it here:
	if(getMatrix) {
	if(khel==0)
	qqb_hel_amps(p1hel,p2hel,k1hel,k2hel,0) = hel_amp;
	else
	qqb_hel_amps(p1hel,p2hel,k1hel,k2hel,2) = hel_amp;
	}
	sum_hel_amps_sqr += norm(hel_amp);
	}
	}
	}
	}
	}

	// Fill up the remaining bits of the production ME, corresponding
	// to longitudinal gluon polarization, with (0.,0.).
	if(getMatrix) {
	for(unsigned int p1hel=0;p1hel<2;++p1hel) {
	for(unsigned int p2hel=0;p2hel<2;++p2hel) {
	for(unsigned int k1hel=0;k1hel<3;++k1hel) {
	for(unsigned int k2hel=0;k2hel<3;++k2hel) {
	qqb_hel_amps(p1hel,p2hel,k1hel,k2hel,1) = Complex(0.,0.);
	}
	}
	}
	}
	}

	// Calculate the production density matrix:
	if(getMatrix) {
	for(unsigned int k1hel=0;k1hel<3;++k1hel) {
	for(unsigned int k1helpr=0;k1helpr<3;++k1helpr) {
	for(unsigned int k2hel=0;k2hel<3;++k2hel) {
	for(unsigned int k2helpr=0;k2helpr<3;++k2helpr) {
	Complex theElement(0.,0.);
	// For each k1hel, k1helpr, k2hel, k2helpr sum over fermion and gluon spins...
	for(unsigned int p1hel=0;p1hel<2;++p1hel) {
	for(unsigned int p2hel=0;p2hel<2;++p2hel) {
	for(unsigned int khel=0;khel<3;khel+=2) {
	theElement += qqb_hel_amps(p1hel,p2hel,k1hel ,k2hel ,khel)
	*conj(qqb_hel_amps(p1hel,p2hel,k1helpr,k2helpr,khel));
	}
	}
	}
	// ...and then set the production matrix element to the sum:
	productionMatrix_[k1hel][k1helpr][k2hel][k2helpr] = theElement;
	}
	}
	}
	}
	}

	// Spin and colour averaging factors = 1/4 * CF * 1/3 = 1/9
	sum_hel_amps_sqr /= 9.;

	// Symmetry factor for identical Z bosons in the final state
	if(k1data->id()==23&&k2data->id()==23) sum_hel_amps_sqr /= 2.;

	return sum_hel_amps_sqrR.tkr()R.ukr()*UnitRemoval::InvE2;
	}

	/***************************************************************************/
	// This is identical to the code in the Powheg matrix element. It should
	// equal t_u_M_R_qg in there, which is supposed to be the real emission ME
	// times tk*uk.
	Energy2 MEPP2VVPowheg::t_u_M_R_qg_hel_amp(realVVKinematics R, bool getMatrix) const {
	using namespace ThePEG::Helicity;

	ProductionMatrixElement qg_hel_amps(PDT::Spin1Half,PDT::Spin1,
	PDT::Spin1,PDT::Spin1,
	PDT::Spin1Half);

	double sum_hel_amps_sqr(0.);

	tcPDPtr p1data(showerQuark_->dataPtr());
	tcPDPtr p2data(getParticleData(ParticleID::g));
	tcPDPtr k1data(V1_->dataPtr());
	tcPDPtr k2data(V2_->dataPtr());
	tcPDPtr kdata (showerAntiquark_->dataPtr()->CC());
	if(k1data->id()==-24&&k2data->id()==24) swap(k1data,k2data);

	SpinorWaveFunction qinSpinor(R.p1r(),p1data,incoming);
	SpinorBarWaveFunction qoutSpinor(R.kr(),kdata,outgoing);
	vector<SpinorWaveFunction> qin;
	vector<SpinorBarWaveFunction> qout;
	for(unsigned int ix=0;ix<2;ix++) {
	qinSpinor.reset(ix);
	qoutSpinor.reset(ix);
	qin.push_back(qinSpinor);
	qout.push_back(qoutSpinor);
	}

	VectorWaveFunction v1Polarization(R.k1r(),k1data,outgoing);
	VectorWaveFunction v2Polarization(R.k2r(),k2data,outgoing);
	vector<VectorWaveFunction> v1;
	vector<VectorWaveFunction> v2;
	for(unsigned int ix=0;ix<3;ix++) {
	v1Polarization.reset(ix);
	v2Polarization.reset(ix);
	v1.push_back(v1Polarization);
	v2.push_back(v2Polarization);
	}

	VectorWaveFunction gPolarization(R.p2r(),p2data,incoming);
	vector<VectorWaveFunction> g;
	for(unsigned int ix=0;ix<3;ix+=2) {
	gPolarization.reset(ix);
	g.push_back(gPolarization);
	}

	AbstractFFVVertexPtr ffg = FFGvertex_;
	AbstractFFVVertexPtr ffv1 = k1data->id()==23 ? FFZvertex_ : FFWvertex_;
	AbstractFFVVertexPtr ffv2 = k2data->id()==23 ? FFZvertex_ : FFWvertex_;

	// Collecting information for intermediate fermions
	vector<tcPDPtr> tc;
	if(abs(k1data->id())==24&&abs(k2data->id())==24) {
	if(abs(p1data->id())%2==0)
	for(int ix=0;ix<3;++ix) tc.push_back(getParticleData(1+2*ix));
	else
	for(int ix=0;ix<3;++ix) tc.push_back(getParticleData(2+2*ix));
	}
	else if(k1data->id()==23&&k2data->id()==23) tc.push_back(p1data);
	else if(abs(k1data->id())==24&&k2data->id()==23) tc.push_back(kdata->CC());

	// Loop over helicities summing the relevant diagrams
	for(unsigned int p1hel=0;p1hel<2;++p1hel) {
	for(unsigned int p2hel=0;p2hel<2;++p2hel) {
	for(unsigned int khel=0;khel<2;++khel) {
	SpinorWaveFunction p1_p2 = ffg->evaluate(QCDScale_,5,p1data,qin[p1hel],g[p2hel]);
	SpinorBarWaveFunction p2_k = ffg->evaluate(QCDScale_,5,kdata->CC(),qout[khel],g[p2hel]);
	for(unsigned int k1hel=0;k1hel<3;++k1hel) {
	for(unsigned int k2hel=0;k2hel<3;++k2hel) {
	// If helicity is exactly conserved (massless quarks) skip if p1hel!=khel
	// but if the production ME is required first fill it with (0.,0.).
	if((p1hel!=khel)&&helicityConservation_) {
	if(getMatrix) {
	if(p2hel==0)
	qg_hel_amps(p1hel,0,k1hel,k2hel,khel) = Complex(0.,0.);
	else
	qg_hel_amps(p1hel,2,k1hel,k2hel,khel) = Complex(0.,0.);
	}
	continue;
	}
	vector<Complex> diagrams;
	// Get all t-channel diagram contributions
	tcPDPtr intermediate_q;
	for(unsigned int ix=0;ix<tc.size();ix++) {
	intermediate_q = (!(k1data->id()==24&&k2data->id()==-24)) ? showerAntiquark_->dataPtr() : tc[ix];
	SpinorWaveFunction p1_v1 = ffv1->evaluate(EWScale_,5,intermediate_q,qin[p1hel],v1[k1hel]);
	SpinorBarWaveFunction k_v2 = ffv2->evaluate(EWScale_,5,intermediate_q,qout[khel],v2[k2hel]);
	// First calculate all the off-shell fermion currents
	// Now calculate the 6 abelian diagrams
	// q+g->v1+v2+q with 2 t-channel propagators, 1 s- and 1 t-channel and 2 t-channel ones.
	if(!((k1data->id()==24&&k2data->id()==-24)&&(abs(p1data->id())%2==1))) {
	diagrams.push_back(ffv2->evaluate(EWScale_,p1_v1,p2_k,v2[k2hel]));
	diagrams.push_back(ffg->evaluate(QCDScale_,p1_v1,k_v2,g[p2hel]));
	diagrams.push_back(ffv1->evaluate(EWScale_,p1_p2,k_v2,v1[k1hel]));
	}
	intermediate_q = (!(k1data->id()==24&&k2data->id()==-24)) ? p1data : tc[ix];
	SpinorWaveFunction p1_v2 = ffv2->evaluate(EWScale_,5,intermediate_q,qin[p1hel],v2[k2hel]);
	SpinorBarWaveFunction k_v1 = ffv1->evaluate(EWScale_,5,intermediate_q,qout[khel],v1[k1hel]);
	// q+g->v2+v1+q, with 2 t-channel propagators, 1 s- and 1 t-channel and 2 t-channel ones.
	if(!((k1data->id()==24&&k2data->id()==-24)&&(abs(p1data->id())%2==0))) {
	diagrams.push_back(ffv1->evaluate(EWScale_,p1_v2,p2_k,v1[k1hel]));
	diagrams.push_back(ffg->evaluate(QCDScale_,p1_v2,k_v1,g[p2hel]));
	diagrams.push_back(ffv2->evaluate(EWScale_,p1_p2,k_v1,v2[k2hel]));
	}
	}
	// Note: choosing 3 as the second argument in WWWvertex_->evaluate()
	// sets option 3 in thepeg/Helicity/Vertex/VertexBase.cc , which
	// means the propagator does not contain a width factor (which is
	// good re. gauge invariance).
	// If W+Z / W-Z calculate the two V+jet-like s-channel diagrams
	if(abs(k1data->id())==24&&k2data->id()==23) {
	// The off-shell s-channel boson current
	VectorWaveFunction k1_k2 =
	WWWvertex_->evaluate(EWScale_,3,k1data->CC(),v2[k2hel],v1[k1hel]);
	// q+qb->g+v1->g+v1+v2, q+qb->v1+g->v1+v2+g
	diagrams.push_back(ffv1->evaluate(EWScale_,p1_p2,qout[khel],k1_k2));
	diagrams.push_back(ffv1->evaluate(EWScale_,qin[p1hel],p2_k,k1_k2));
	}
	// If W+W- calculate the four V+jet-like s-channel diagrams
	if((k1data->id()==24&&k2data->id()==-24)&&(p1data->id()==kdata->id())) {
	// The off-shell s-channel boson current
	VectorWaveFunction k1_k2;
	// q+qb->g+Z0->g+v1+v2,q+qb->Z0+g->v1+v2+g,
	tcPDPtr Z0 = getParticleData(ParticleID::Z0);
	k1_k2 = WWWvertex_->evaluate(EWScale_,3,Z0,v2[k2hel],v1[k1hel]);
	diagrams.push_back(FFZvertex_->evaluate(EWScale_,p1_p2,qout[khel],k1_k2));
	diagrams.push_back(FFZvertex_->evaluate(EWScale_,qin[p1hel],p2_k,k1_k2));
	// q+qb->g+gamma->g+v1+v2,q+qb->gamma+g->v1+v2+g,
	tcPDPtr gamma = getParticleData(ParticleID::gamma);
	k1_k2 = WWWvertex_->evaluate(EWScale_,3,gamma,v2[k2hel],v1[k1hel]);
	diagrams.push_back(FFPvertex_->evaluate(EWScale_,p1_p2,qout[khel],k1_k2));
	diagrams.push_back(FFPvertex_->evaluate(EWScale_,qin[p1hel],p2_k,k1_k2));
	}
	// Add up all diagrams to get the total amplitude:
	Complex hel_amp(0.);
	for(unsigned int ix=0;ix<diagrams.size();ix++) hel_amp += diagrams[ix];
	// If we need to fill the production ME we do it here:
	if(getMatrix) {
	if(p2hel==0)
	qg_hel_amps(p1hel,0,k1hel,k2hel,khel) = hel_amp;
	else
	qg_hel_amps(p1hel,2,k1hel,k2hel,khel) = hel_amp;
	}
	sum_hel_amps_sqr += norm(hel_amp);
	}
	}
	}
	}
	}

	// Fill up the remaining bits of the production ME, corresponding
	// to longitudinal gluon polarization, with (0.,0.).
	if(getMatrix) {
	for(unsigned int p1hel=0;p1hel<2;++p1hel) {
	for(unsigned int k1hel=0;k1hel<3;++k1hel) {
	for(unsigned int k2hel=0;k2hel<3;++k2hel) {
	for(unsigned int khel=0;khel<2;++khel) {
	qg_hel_amps(p1hel,1,k1hel,k2hel,khel) = Complex(0.,0.);
	}
	}
	}
	}
	}

	// Calculate the production density matrix:
	if(getMatrix) {
	for(unsigned int k1hel=0;k1hel<3;++k1hel) {
	for(unsigned int k1helpr=0;k1helpr<3;++k1helpr) {
	for(unsigned int k2hel=0;k2hel<3;++k2hel) {
	for(unsigned int k2helpr=0;k2helpr<3;++k2helpr) {
	Complex theElement(0.,0.);
	// For each k1hel, k1helpr, k2hel, k2helpr sum over fermion and gluon spins...
	for(unsigned int p1hel=0;p1hel<2;++p1hel) {
	for(unsigned int p2hel=0;p2hel<3;p2hel+=2) {
	for(unsigned int khel=0;khel<2;++khel) {
	theElement += qg_hel_amps(p1hel,p2hel,k1hel ,k2hel ,khel)
	*conj(qg_hel_amps(p1hel,p2hel,k1helpr,k2helpr,khel));
	}
	}
	}
	// ...and then set the production matrix element to the sum:
	productionMatrix_[k1hel][k1helpr][k2hel][k2helpr] = theElement;
	}
	}
	}
	}
	}

	// Spin and colour averaging factors = 1/4 * TR * 1/3 = 1/24
	sum_hel_amps_sqr /= 24.;

	// Symmetry factor for identical Z bosons in the final state
	if(k1data->id()==23&&k2data->id()==23) sum_hel_amps_sqr /= 2.;

	return sum_hel_amps_sqrR.tkr()R.ukr()*UnitRemoval::InvE2;
	}

	/***************************************************************************/
	// This is identical to the code in the Powheg matrix element. It should
	// equal t_u_M_R_gqb in there, which is supposed to be the real emission ME
	// times tk*uk.
	Energy2 MEPP2VVPowheg::t_u_M_R_gqb_hel_amp(realVVKinematics R, bool getMatrix) const {
	using namespace ThePEG::Helicity;

	ProductionMatrixElement gqb_hel_amps(PDT::Spin1,PDT::Spin1Half,
	PDT::Spin1,PDT::Spin1,
	PDT::Spin1Half);

	double sum_hel_amps_sqr(0.);

	tcPDPtr p1data(getParticleData(ParticleID::g));
	tcPDPtr p2data(showerAntiquark_->dataPtr());
	tcPDPtr k1data(V1_->dataPtr());
	tcPDPtr k2data(V2_->dataPtr());
	tcPDPtr kdata (showerQuark_->dataPtr()->CC());
	if(k1data->id()==-24&&k2data->id()==24) swap(k1data,k2data);

	SpinorBarWaveFunction qbinSpinor(R.p2r(),p2data,incoming);
	SpinorWaveFunction qboutSpinor(R.kr(),kdata,outgoing);
	vector<SpinorBarWaveFunction> qbin;
	vector<SpinorWaveFunction> qbout;
	for(unsigned int ix=0;ix<2;ix++) {
	qbinSpinor.reset(ix);
	qboutSpinor.reset(ix);
	qbin.push_back(qbinSpinor);
	qbout.push_back(qboutSpinor);
	}

	VectorWaveFunction v1Polarization(R.k1r(),k1data,outgoing);
	VectorWaveFunction v2Polarization(R.k2r(),k2data,outgoing);
	vector<VectorWaveFunction> v1;
	vector<VectorWaveFunction> v2;
	for(unsigned int ix=0;ix<3;ix++) {
	v1Polarization.reset(ix);
	v2Polarization.reset(ix);
	v1.push_back(v1Polarization);
	v2.push_back(v2Polarization);
	}

	VectorWaveFunction gPolarization(R.p1r(),p1data,incoming);
	vector<VectorWaveFunction> g;
	for(unsigned int ix=0;ix<3;ix+=2) {
	gPolarization.reset(ix);
	g.push_back(gPolarization);
	}

	AbstractFFVVertexPtr ffg = FFGvertex_;
	AbstractFFVVertexPtr ffv1 = k1data->id()==23 ? FFZvertex_ : FFWvertex_;
	AbstractFFVVertexPtr ffv2 = k2data->id()==23 ? FFZvertex_ : FFWvertex_;

	// Collecting information for intermediate fermions
	vector<tcPDPtr> tc;
	if(abs(k1data->id())==24&&abs(k2data->id())==24) {
	if(abs(p2data->id())%2==0)
	for(int ix=0;ix<3;++ix) tc.push_back(getParticleData(1+2*ix));
	else
	for(int ix=0;ix<3;++ix) tc.push_back(getParticleData(2+2*ix));
	}
	else if(k1data->id()==23&&k2data->id()==23) tc.push_back(p2data);
	else if(abs(k1data->id())==24&&k2data->id()==23) tc.push_back(kdata->CC());

	// Loop over helicities summing the relevant diagrams
	for(unsigned int p1hel=0;p1hel<2;++p1hel) {
	for(unsigned int p2hel=0;p2hel<2;++p2hel) {
	for(unsigned int khel=0;khel<2;++khel) {
	SpinorBarWaveFunction p1_p2 = ffg->evaluate(QCDScale_,5,p2data,qbin[p2hel],g[p1hel]);
	SpinorWaveFunction p1_k = ffg->evaluate(QCDScale_,5,kdata->CC(),qbout[khel],g[p1hel]);
	for(unsigned int k1hel=0;k1hel<3;++k1hel) {
	for(unsigned int k2hel=0;k2hel<3;++k2hel) {
	// If helicity is exactly conserved (massless quarks) skip if p2hel!=khel
	// but if the production ME is required first fill it with (0.,0.).
	if((p2hel!=khel)&&helicityConservation_) {
	if(getMatrix) {
	if(p1hel==0)
	gqb_hel_amps(0,p2hel,k1hel,k2hel,khel) = Complex(0.,0.);
	else
	gqb_hel_amps(2,p2hel,k1hel,k2hel,khel) = Complex(0.,0.);
	}
	continue;
	}
	vector<Complex> diagrams;
	// Get all t-channel diagram contributions
	tcPDPtr intermediate_q;
	for(unsigned int ix=0;ix<tc.size();ix++) {
	intermediate_q = (!(k1data->id()==24&&k2data->id()==-24)) ? showerQuark_->dataPtr() : tc[ix];
	SpinorBarWaveFunction p2_v1 = ffv1->evaluate(EWScale_,5,intermediate_q,qbin[p2hel],v1[k1hel]);
	SpinorWaveFunction k_v2 = ffv2->evaluate(EWScale_,5,intermediate_q,qbout[khel],v2[k2hel]);
	// First calculate all the off-shell fermion currents
	// Now calculate the 6 abelian diagrams q+g->v1+v2+q
	// with 2 t-channel propagators, 1 s- and 1 t-channel
	// and 2 t-channel ones.
	if(!((k1data->id()==24&&k2data->id()==-24)&&(abs(p2data->id())%2==0))) {
	diagrams.push_back(ffv2->evaluate(EWScale_,p1_k,p2_v1,v2[k2hel]));
	diagrams.push_back(ffg->evaluate(QCDScale_,k_v2,p2_v1,g[p1hel]));
	diagrams.push_back(ffv1->evaluate(EWScale_,k_v2,p1_p2,v1[k1hel]));
	}
	intermediate_q = (!(k1data->id()==24&&k2data->id()==-24)) ? p2data : tc[ix];
	SpinorBarWaveFunction p2_v2 = ffv2->evaluate(EWScale_,5,intermediate_q,qbin[p2hel],v2[k2hel]);
	SpinorWaveFunction k_v1 = ffv1->evaluate(EWScale_,5,intermediate_q,qbout[khel],v1[k1hel]);
	// q+g->v2+v1+q, with 2 t-channel propagators, 1 s- and 1 t-channel and 2 t-channel ones.
	if(!((k1data->id()==24&&k2data->id()==-24)&&(abs(p2data->id())%2==1))) {
	diagrams.push_back(ffv1->evaluate(EWScale_,p1_k,p2_v2,v1[k1hel]));
	diagrams.push_back(ffg->evaluate(QCDScale_,k_v1,p2_v2,g[p1hel]));
	diagrams.push_back(ffv2->evaluate(EWScale_,k_v1,p1_p2,v2[k2hel]));
	}
	}
	// Note: choosing 3 as the second argument in WWWvertex_->evaluate()
	// sets option 3 in thepeg/Helicity/Vertex/VertexBase.cc , which
	// means the propagator does not contain a width factor (which is
	// good re. gauge invariance).
	// If W+Z / W-Z calculate the two V+jet-like s-channel diagrams
	if(abs(k1data->id())==24&&k2data->id()==23) {
	// The off-shell s-channel boson current
	VectorWaveFunction k1_k2 =
	WWWvertex_->evaluate(EWScale_,3,k1data->CC(),v2[k2hel],v1[k1hel]);
	// q+qb->g+v1->g+v1+v2, q+qb->v1+g->v1+v2+g
	diagrams.push_back(ffv1->evaluate(EWScale_,qbout[khel],p1_p2,k1_k2));
	diagrams.push_back(ffv1->evaluate(EWScale_,p1_k,qbin[p2hel],k1_k2));
	}
	// If W+W- calculate the four V+jet-like s-channel diagrams
	if((k1data->id()==24&&k2data->id()==-24)&&(p2data->id()==kdata->id())) {
	// The off-shell s-channel boson current
	VectorWaveFunction k1_k2;
	// q+qb->g+Z0->g+v1+v2,q+qb->Z0+g->v1+v2+g,
	tcPDPtr Z0 = getParticleData(ParticleID::Z0);
	k1_k2 = WWWvertex_->evaluate(EWScale_,3,Z0,v2[k2hel],v1[k1hel]);
	diagrams.push_back(FFZvertex_->evaluate(EWScale_,qbout[khel],p1_p2,k1_k2));
	diagrams.push_back(FFZvertex_->evaluate(EWScale_,p1_k,qbin[p2hel],k1_k2));
	// q+qb->g+gamma->g+v1+v2,q+qb->gamma+g->v1+v2+g,
	tcPDPtr gamma = getParticleData(ParticleID::gamma);
	k1_k2 = WWWvertex_->evaluate(EWScale_,3,gamma,v2[k2hel],v1[k1hel]);
	diagrams.push_back(FFPvertex_->evaluate(EWScale_,qbout[khel],p1_p2,k1_k2));
	diagrams.push_back(FFPvertex_->evaluate(EWScale_,p1_k,qbin[p2hel],k1_k2));
	}
	// Add up all diagrams to get the total amplitude:
	Complex hel_amp(0.);
	for(unsigned int ix=0;ix<diagrams.size();ix++) hel_amp += diagrams[ix];
	// If we need to fill the production ME we do it here:
	if(getMatrix) {
	if(p1hel==0)
	gqb_hel_amps(0,p2hel,k1hel,k2hel,khel) = hel_amp;
	else
	gqb_hel_amps(2,p2hel,k1hel,k2hel,khel) = hel_amp;
	}
	sum_hel_amps_sqr += norm(hel_amp);
	}
	}
	}
	}
	}

	// Fill up the remaining bits of the production ME, corresponding
	// to longitudinal gluon polarization, with (0.,0.).
	if(getMatrix) {
	for(unsigned int p2hel=0;p2hel<2;++p2hel) {
	for(unsigned int k1hel=0;k1hel<3;++k1hel) {
	for(unsigned int k2hel=0;k2hel<3;++k2hel) {
	for(unsigned int khel=0;khel<2;++khel) {
	gqb_hel_amps(1,p2hel,k1hel,k2hel,khel) = Complex(0.,0.);
	}
	}
	}
	}
	}

	// Calculate the production density matrix:
	if(getMatrix) {
	for(unsigned int k1hel=0;k1hel<3;++k1hel) {
	for(unsigned int k1helpr=0;k1helpr<3;++k1helpr) {
	for(unsigned int k2hel=0;k2hel<3;++k2hel) {
	for(unsigned int k2helpr=0;k2helpr<3;++k2helpr) {
	Complex theElement(0.,0.);
	// For each k1hel, k1helpr, k2hel, k2helpr sum over fermion and gluon spins...
	for(unsigned int p1hel=0;p1hel<3;p1hel+=2) {
	for(unsigned int p2hel=0;p2hel<2;++p2hel) {
	for(unsigned int khel=0;khel<2;++khel) {
	theElement += gqb_hel_amps(p1hel,p2hel,k1hel ,k2hel ,khel)
	*conj(gqb_hel_amps(p1hel,p2hel,k1helpr,k2helpr,khel));
	}
	}
	}
	// ...and then set the production matrix element to the sum:
	productionMatrix_[k1hel][k1helpr][k2hel][k2helpr] = theElement;
	}
	}
	}
	}
	}

	// Spin and colour averaging factors = 1/4 * TR * 1/3 = 1/24
	sum_hel_amps_sqr /= 24.;

	// Symmetry factor for identical Z bosons in the final state
	if(k1data->id()==23&&k2data->id()==23) sum_hel_amps_sqr /= 2.;

	return sum_hel_amps_sqrR.tkr()R.ukr()*UnitRemoval::InvE2;
	}


	/***************************************************************************/
	// This returns exactly the same value as lo_me2_ when you put it in MEPP2VVPowheg.cc
	double MEPP2VVPowheg::lo_me(bool getMatrix) const {
	using namespace ThePEG::Helicity;

	ProductionMatrixElement lo_hel_amps(PDT::Spin1Half,PDT::Spin1Half,
	PDT::Spin1 ,PDT::Spin1);

	double sum_hel_amps_sqr(0.);

	tcPDPtr p1data(showerQuark_->dataPtr());
	tcPDPtr p2data(showerAntiquark_->dataPtr());
	tcPDPtr k1data(V1_->dataPtr());
	tcPDPtr k2data(V2_->dataPtr());
	if(k1data->id()==-24&&k2data->id()==24) swap(k1data,k2data); // Should never actually occur.

	// If you want to reproduce the spin correlations of MEPP2VV
	// you should evaluate this ME using the lab frame momenta
	// instead of the bornVVKinematics ones (partonic C.O.M. frame).
	SpinorWaveFunction qSpinor;
	SpinorBarWaveFunction qbSpinor;
	if(!getMatrix) {
	qSpinor=SpinorWaveFunction(B_.p1b(),p1data,incoming);
	qbSpinor=SpinorBarWaveFunction(B_.p2b(),p2data,incoming);
	} else {
	qSpinor=SpinorWaveFunction(showerQuark_->momentum(),p1data,incoming);
	qbSpinor=SpinorBarWaveFunction(showerAntiquark_->momentum(),p2data,incoming);
	}
	vector<SpinorWaveFunction> q;
	vector<SpinorBarWaveFunction> qb;
	for(unsigned int ix=0;ix<2;ix++) {
	qSpinor.reset(ix);
	qbSpinor.reset(ix);
	q.push_back(qSpinor);
	qb.push_back(qbSpinor);
	}

	// If you want to reproduce the spin correlations of MEPP2VV
	// you should evaluate this ME using the lab frame momenta
	// instead of the bornVVKinematics ones (partonic C.O.M. frame).
	VectorWaveFunction v1Polarization;
	VectorWaveFunction v2Polarization;
	if(!getMatrix) {
	v1Polarization=VectorWaveFunction(B_.k1b(),k1data,outgoing);
	v2Polarization=VectorWaveFunction(B_.k2b(),k2data,outgoing);
	} else {
	v1Polarization=VectorWaveFunction(V1_->momentum(),k1data,outgoing);
	v2Polarization=VectorWaveFunction(V2_->momentum(),k2data,outgoing);
	}
	vector<VectorWaveFunction> v1;
	vector<VectorWaveFunction> v2;
	for(unsigned int ix=0;ix<3;ix++) {
	v1Polarization.reset(ix);
	v2Polarization.reset(ix);
	v1.push_back(v1Polarization);
	v2.push_back(v2Polarization);
	}

	AbstractFFVVertexPtr ffv1 = k1data->id()==23 ? FFZvertex_ : FFWvertex_;
	AbstractFFVVertexPtr ffv2 = k2data->id()==23 ? FFZvertex_ : FFWvertex_;

	// Collecting information for intermediate fermions
	vector<tcPDPtr> tc;
	if(abs(k1data->id())==24&&abs(k2data->id())==24) {
	if(abs(p1data->id())%2==0)
	for(int ix=0;ix<3;++ix) tc.push_back(getParticleData(1+2*ix));
	else
	for(int ix=0;ix<3;++ix) tc.push_back(getParticleData(2+2*ix));
	}
	else if(k1data->id()==23&&k2data->id()==23) tc.push_back(p1data);
	else if(abs(k1data->id())==24&&k2data->id()==23) tc.push_back(p2data);

	// Loop over helicities summing the relevant diagrams
	for(unsigned int p1hel=0;p1hel<2;++p1hel) {
	for(unsigned int p2hel=0;p2hel<2;++p2hel) {
	for(unsigned int k1hel=0;k1hel<3;++k1hel) {
	for(unsigned int k2hel=0;k2hel<3;++k2hel) {
	if((p1hel==p2hel)&&helicityConservation_) {
	lo_hel_amps(p1hel,p2hel,k1hel,k2hel) = Complex(0.,0.);
	continue;
	}
	vector<Complex> diagrams;
	// Get all t-channel diagram contributions
	tcPDPtr intermediate_t;
	for(unsigned int ix=0;ix<tc.size();ix++) {
	intermediate_t = (!(k1data->id()==24&&k2data->id()==-24)) ? p2data : tc[ix];
	SpinorWaveFunction p1_v1 = ffv1->evaluate(EWScale_,5,intermediate_t,q[p1hel],v1[k1hel]);
	// First calculate all the off-shell fermion currents
	// Now calculate the 6 t-channel diagrams
	// q+qb->v1+v2
	if(!((k1data->id()==24&&k2data->id()==-24)&&(abs(p1data->id())%2==1)))
	diagrams.push_back(ffv2->evaluate(EWScale_,p1_v1,qb[p2hel],v2[k2hel]));
	intermediate_t = (!(k1data->id()==24&&k2data->id()==-24)) ? p1data : tc[ix];
	SpinorWaveFunction p1_v2 = ffv2->evaluate(EWScale_,5,intermediate_t,q[p1hel],v2[k2hel]);
	// q+qb->v2+v1
	if(!((k1data->id()==24&&k2data->id()==-24)&&(abs(p1data->id())%2==0)))
	diagrams.push_back(ffv1->evaluate(EWScale_,p1_v2,qb[p2hel],v1[k1hel]));
	}
	// Note: choosing 3 as the second argument in WWWvertex_->evaluate()
	// sets option 3 in thepeg/Helicity/Vertex/VertexBase.cc , which
	// means the propagator does not contain a width factor (which is
	// good re. gauge invariance).
	// If W+Z / W-Z calculate the two V+jet-like s-channel diagrams
	if(abs(k1data->id())==24&&k2data->id()==23) {
	// The off-shell s-channel boson current
	VectorWaveFunction k1_k2 =
	WWWvertex_->evaluate(EWScale_,3,k1data->CC(),v2[k2hel],v1[k1hel]);
	// q+qb->v1*->v1+v2
	diagrams.push_back(ffv1->evaluate(EWScale_,q[p1hel],qb[p2hel],k1_k2));
	}
	// If W+W- calculate the four V+jet-like s-channel diagrams
	if((k1data->id()==24&&k2data->id()==-24)&&(p1data->id()==-p2data->id())) {
	// The off-shell s-channel boson current
	VectorWaveFunction k1_k2;
	// q+qb->Z0*->v1+v2
	tcPDPtr Z0 = getParticleData(ParticleID::Z0);
	k1_k2 = WWWvertex_->evaluate(EWScale_,3,Z0,v2[k2hel],v1[k1hel]);
	diagrams.push_back(FFZvertex_->evaluate(EWScale_,q[p1hel],qb[p2hel],k1_k2));
	// q+qb->gamma*->v1+v2
	tcPDPtr gamma = getParticleData(ParticleID::gamma);
	k1_k2 = WWWvertex_->evaluate(EWScale_,3,gamma,v2[k2hel],v1[k1hel]);
	diagrams.push_back(FFPvertex_->evaluate(EWScale_,q[p1hel],qb[p2hel],k1_k2));
	}
	// Add up all diagrams to get the total amplitude:
	Complex hel_amp(0.);
	for(unsigned int ix=0;ix<diagrams.size();ix++) hel_amp += diagrams[ix];
	// If we need to fill the production ME we do it here:
	if(getMatrix) lo_hel_amps(p1hel,p2hel,k1hel,k2hel) = hel_amp;
	sum_hel_amps_sqr += norm(hel_amp);
	}
	}
	}
	}

	// Calculate the production density matrix:
	if(getMatrix) {
	for(unsigned int k1hel=0;k1hel<3;++k1hel) {
	for(unsigned int k1helpr=0;k1helpr<3;++k1helpr) {
	for(unsigned int k2hel=0;k2hel<3;++k2hel) {
	for(unsigned int k2helpr=0;k2helpr<3;++k2helpr) {
	Complex theElement(0.,0.);
	// For each k1hel, k1helpr, k2hel, k2helpr sum over the fermion spins...
	for(unsigned int p1hel=0;p1hel<2;++p1hel) {
	for(unsigned int p2hel=0;p2hel<2;++p2hel) {
	if((p1hel==p2hel)&&helicityConservation_) continue;
	theElement += lo_hel_amps(p1hel,p2hel,k1hel ,k2hel )
	*conj(lo_hel_amps(p1hel,p2hel,k1helpr,k2helpr));
	}
	}
	// ...and then set the production matrix element to the sum:
	productionMatrix_[k1hel][k1helpr][k2hel][k2helpr] = theElement;
	}
	}
	}
	}
	}

	// Spin and colour averaging factors = 1/4 * 1/3 = 1/12
	sum_hel_amps_sqr /= 12.;

	// Symmetry factor for identical Z bosons in the final state
	if(k1data->id()==23&&k2data->id()==23) sum_hel_amps_sqr /= 2.;

	return sum_hel_amps_sqr;
	}

	/***************************************************************************/
	// This member selects a [2-body] decay mode and assigns children to the
	// vector bosons with momenta which are isotropic in their rest frames.
	bool MEPP2VVPowheg::isotropicDecayer() {
	using namespace ThePEG::Helicity;

	// Generate the children's momenta isotropically in
	// the rest frames of V1 and V2:
	double cth,phi;
	// First V1's children:
	cth = UseRandom::rnd()*2.-1.;
	phi = UseRandom::rnd()2.Constants::pi;
	Energy m1(V1_->momentum().m());
	Energy m3(children_[0]->data().constituentMass());
	Energy m4(children_[1]->data().constituentMass());
	Energy p34(triangleFn(sqr(m1),sqr(m3),sqr(m4))
	/2./m1);
	if(isnan(p34/GeV)\|\|cth>1.\|\|cth<-1.) return false;
	Energy pT34(p34sqrt(1.-cth)sqrt(1.+cth));
	Lorentz5Momentum k3(pT34sin(phi),pT34cos(phi),p34 *cth,
	sqrt(p34*p34+sqr(m3)),m3);
	Lorentz5Momentum k4(-k3);
	k4.setE(sqrt(p34*p34+sqr(m4)));
	k4.setTau(m4);
	Boost boostToV1RF(R_.k1r().boostVector());
	k3.boost(boostToV1RF);
	k3.rescaleRho();
	k4.boost(boostToV1RF);
	k4.rescaleRho();

	// Second V2's children:
	cth = UseRandom::rnd()*2.-1.;
	phi = UseRandom::rnd()2.Constants::pi;
	Energy m2(V2_->momentum().m());
	Energy m5(children_[2]->data().constituentMass());
	Energy m6(children_[3]->data().constituentMass());
	Energy p56(triangleFn(sqr(m2),sqr(m5),sqr(m6))
	/2./m2);
	if(isnan(p56/GeV)\|\|cth>1.\|\|cth<-1.) return false;
	Energy pT56(p56sqrt(1.-cth)sqrt(1.+cth));
	Lorentz5Momentum k5(pT56sin(phi),pT56cos(phi),p56*cth,
	sqrt(p56*p56+sqr(m5)),m5);
	Lorentz5Momentum k6(-k5);
	k6.setE(sqrt(p56*p56+sqr(m6)));
	k6.setTau(m6);
	Boost boostToV2RF(R_.k2r().boostVector());
	k5.boost(boostToV2RF);
	k5.rescaleRho();
	k6.boost(boostToV2RF);
	k6.rescaleRho();

	// Assign the momenta to the children:
	children_[0]->set5Momentum(k3);
	children_[1]->set5Momentum(k4);
	children_[2]->set5Momentum(k5);
	children_[3]->set5Momentum(k6);
	return true;

	}

	// Override 2->2 production matrix here:
	void MEPP2VVPowheg::recalculateVertex() {

	// Zero the squared amplitude; this equals sum_hel_amps_sqr if all
	// is working as it should:
	Complex productionMatrix2(0.,0.);
	for(unsigned int k1hel=0;k1hel<3;++k1hel)
	for(unsigned int k2hel=0;k2hel<3;++k2hel)
	productionMatrix2 += productionMatrix_[k1hel][k1hel][k2hel][k2hel];

	// Get the vector wavefunctions:
	VectorWaveFunction v1Polarization;
	VectorWaveFunction v2Polarization;
	v1Polarization=VectorWaveFunction(R_.k1r(),V1_->dataPtr(),outgoing);
	v2Polarization=VectorWaveFunction(R_.k2r(),V2_->dataPtr(),outgoing);
	vector<VectorWaveFunction> v1;
	vector<VectorWaveFunction> v2;
	for(unsigned int ix=0;ix<3;ix++) {
	v1Polarization.reset(ix);
	v2Polarization.reset(ix);
	v1.push_back(v1Polarization);
	v2.push_back(v2Polarization);
	}

	AbstractFFVVertexPtr ffv1 = V1_->id()==23 ? FFZvertex_ : FFWvertex_;
	AbstractFFVVertexPtr ffv2 = V2_->id()==23 ? FFZvertex_ : FFWvertex_;

	bool vetoed(true);
	while(vetoed) {
	// Decay the bosons isotropically in their rest frames:
	isotropicDecayer();

	// Get the spinor wavefunctions:
	SpinorWaveFunction k3Spinor(children_[0]->momentum(),children_[0]->dataPtr(),outgoing);
	SpinorBarWaveFunction k4Spinor(children_[1]->momentum(),children_[1]->dataPtr(),outgoing);
	SpinorWaveFunction k5Spinor(children_[2]->momentum(),children_[2]->dataPtr(),outgoing);
	SpinorBarWaveFunction k6Spinor(children_[3]->momentum(),children_[3]->dataPtr(),outgoing);
	vector<SpinorWaveFunction> k3,k5;
	vector<SpinorBarWaveFunction> k4,k6;
	for(unsigned int ix=0;ix<2;ix++) {
	k3Spinor.reset(ix);
	k4Spinor.reset(ix);
	k3.push_back(k3Spinor);
	k4.push_back(k4Spinor);
	k5Spinor.reset(ix);
	k6Spinor.reset(ix);
	k5.push_back(k5Spinor);
	k6.push_back(k6Spinor);
	}

	DecayMatrixElement decayAmps(PDT::Spin1,PDT::Spin1Half,PDT::Spin1Half);

	for(unsigned int k1hel=0;k1hel<3;++k1hel) {
	for(unsigned int k3hel=0;k3hel<2;++k3hel) {
	for(unsigned int k4hel=0;k4hel<2;++k4hel) {
	decayAmps(k1hel,k3hel,k4hel) =
	ffv1->evaluate(EWScale_,k3[k3hel],k4[k4hel],v1[k1hel]);
	}
	}
	}
	Complex V1decayMatrix[3][3];
	for(unsigned int k1hel=0;k1hel<3;++k1hel) {
	for(unsigned int k1helpr=0;k1helpr<3;++k1helpr) {
	Complex theElement(0.,0.);
	for(unsigned int k3hel=0;k3hel<2;++k3hel) {
	for(unsigned int k4hel=0;k4hel<2;++k4hel) {
	theElement += decayAmps(k1hel,k3hel,k4hel)
	*conj(decayAmps(k1helpr,k3hel,k4hel));
	}
	}
	V1decayMatrix[k1hel][k1helpr] = theElement;
	}
	}
	Complex V1decayMatrix2(0.,0.);
	for(unsigned int k1hel=0;k1hel<3;++k1hel) V1decayMatrix2 += V1decayMatrix[k1hel][k1hel];

	for(unsigned int k2hel=0;k2hel<3;++k2hel) {
	for(unsigned int k5hel=0;k5hel<2;++k5hel) {
	for(unsigned int k6hel=0;k6hel<2;++k6hel) {
	decayAmps(k2hel,k5hel,k6hel) =
	ffv2->evaluate(EWScale_,k5[k5hel],k6[k6hel],v2[k2hel]);
	}
	}
	}
	Complex V2decayMatrix[3][3];
	for(unsigned int k2hel=0;k2hel<3;++k2hel) {
	for(unsigned int k2helpr=0;k2helpr<3;++k2helpr) {
	Complex theElement(0.,0.);
	for(unsigned int k5hel=0;k5hel<2;++k5hel) {
	for(unsigned int k6hel=0;k6hel<2;++k6hel) {
	theElement += decayAmps(k2hel,k5hel,k6hel)
	*conj(decayAmps(k2helpr,k5hel,k6hel));
	}
	}
	V2decayMatrix[k2hel][k2helpr] = theElement;
	}
	}
	Complex V2decayMatrix2(0.,0.);
	for(unsigned int k2hel=0;k2hel<3;++k2hel) V2decayMatrix2 += V2decayMatrix[k2hel][k2hel];

	// Contract the production matrix and the decay matrices:
	Complex meTimesV1V2denominators(0.,0.);
	for(unsigned int k1hel=0;k1hel<3;++k1hel) {
	for(unsigned int k1helpr=0;k1helpr<3;++k1helpr) {
	for(unsigned int k2hel=0;k2hel<3;++k2hel) {
	for(unsigned int k2helpr=0;k2helpr<3;++k2helpr) {
	meTimesV1V2denominators +=
	productionMatrix_[k1hel][k1helpr][k2hel][k2helpr]
	*V1decayMatrix[k1hel][k1helpr]
	*V2decayMatrix[k2hel][k2helpr];
	}
	}
	}
	}

	if(imag(meTimesV1V2denominators)/real(meTimesV1V2denominators)>1.e-7)
	cout << "MEPP2VVPowheg warning\n"
	<< "the matrix element's imaginary part is large "
	<< meTimesV1V2denominators << endl;
	if(imag(productionMatrix2)/real(productionMatrix2)>1.e-7)
	cout << "MEPP2VVPowheg warning\n"
	<< "the production matrix element's imaginary part is large "
	<< productionMatrix2 << endl;
	if(imag(V1decayMatrix2)/real(V1decayMatrix2)>1.e-7)
	cout << "MEPP2VVPowheg warning\n"
	<< "the V1 decay matrix element's imaginary part is large "
	<< V1decayMatrix2 << endl;
	if(imag(V2decayMatrix2)/real(V2decayMatrix2)>1.e-7)
	cout << "MEPP2VVPowheg warning\n"
	<< "the V2 decay matrix element's imaginary part is large "
	<< V2decayMatrix2 << endl;

	// Need branching ratio at least in here I would think --->
	double decayWeight( real(meTimesV1V2denominators)
	/ real(productionMatrix2V1decayMatrix2V2decayMatrix2));
	if(decayWeight>1.)
	cout << "MEPP2VVPowheg::recalculateVertex decayWeight > 1., decayWeight = "
	<< decayWeight << endl;
	if(decayWeight<0.)
	cout << "MEPP2VVPowheg::recalculateVertex decayWeight < 0., decayWeight = "
	<< decayWeight << endl;
	if(UseRandom::rnd()<decayWeight) vetoed = false;
	else vetoed = true;
	}

	return;

	}

	Energy2 MEPP2VVPowheg::triangleFn(Energy2 m12,Energy2 m22, Energy2 m32) {
	Energy4 lambda2(m12m12+m22m22+m32m32-2.m12m22-2.m12m32-2.m22*m32);
	if(lambda2>=ZERO) {
	return sqrt(lambda2);
	} else {
	generator()->log()
	<< "MEPP2VVPowheg::triangleFn "
	<< "kinematic instability, imaginary triangle function\n";
	return -999999.*GeV2;
	}
	}
	diff --git a/MatrixElement/Powheg/MEPP2ZHPowheg.cc b/MatrixElement/Powheg/MEPP2ZHPowheg.cc
	--- a/MatrixElement/Powheg/MEPP2ZHPowheg.cc
	+++ b/MatrixElement/Powheg/MEPP2ZHPowheg.cc
	@@ -1,389 +1,388 @@
	// -- C++ --
	//
	// This is the implementation of the non-inlined, non-templated member
	// functions of the MEPP2ZHPowheg class.
	//

	#include "MEPP2ZHPowheg.h"
	#include "ThePEG/Interface/Parameter.h"
	#include "ThePEG/Interface/ClassDocumentation.h"
	#include "ThePEG/Interface/Switch.h"
	#include "ThePEG/Persistency/PersistentOStream.h"
	#include "ThePEG/Persistency/PersistentIStream.h"
	#include "ThePEG/Handlers/StandardXComb.h"
	#include "ThePEG/PDT/EnumParticles.h"
	#include "ThePEG/MatrixElement/Tree2toNDiagram.h"
	#include "ThePEG/PDT/DecayMode.h"

	using namespace Herwig;

	MEPP2ZHPowheg::MEPP2ZHPowheg()
	: _gluon(), TR_(0.5), CF_(4./3.),
	_contrib(1) ,_nlo_alphaS_opt(0), _fixed_alphaS(0.115895),
	_a(0.5) ,_p(0.7) , _eps(1.0e-8), _scaleopt(1),
	_fixedScale(100.*GeV), _scaleFact(1.)
	{}

	void MEPP2ZHPowheg::persistentOutput(PersistentOStream & os) const {
	os << _contrib << _nlo_alphaS_opt << _fixed_alphaS
	<< _a << _p << _gluon
	<< _scaleopt
	<< ounit(_fixedScale,GeV) << _scaleFact;
	}

	void MEPP2ZHPowheg::persistentInput(PersistentIStream & is, int) {
	is >> _contrib >> _nlo_alphaS_opt >> _fixed_alphaS
	>> _a >> _p >> _gluon
	>> _scaleopt
	>> iunit(_fixedScale,GeV) >> _scaleFact;

	}

	ClassDescription<MEPP2ZHPowheg> MEPP2ZHPowheg::initMEPP2ZHPowheg;
	// Definition of the static class description member.

	void MEPP2ZHPowheg::Init() {

	static ClassDocumentation<MEPP2ZHPowheg> documentation
	("The MEPP2ZHPowheg class implements the matrix element for q qbar -> Z H",
	"The PP$\\to$Z Higgs POWHEG matrix element is described in \\cite{Hamilton:2009za}.",
	- "%\\cite{Hamilton:2009za}\n"
	"\\bibitem{Hamilton:2009za}\n"
	" K.~Hamilton, P.~Richardson and J.~Tully,\n"
	" %``A Positive-Weight Next-to-Leading Order Monte Carlo Simulation for Higgs\n"
	" %Boson Production,''\n"
	" JHEP {\\bf 0904} (2009) 116\n"
	" [arXiv:0903.4345 [hep-ph]].\n"
	" %%CITATION = JHEPA,0904,116;%%\n"
	);



	static Switch<MEPP2ZHPowheg,unsigned int> interfaceContribution
	("Contribution",
	"Which contributions to the cross section to include",
	&MEPP2ZHPowheg::_contrib, 1, false, false);
	static SwitchOption interfaceContributionLeadingOrder
	(interfaceContribution,
	"LeadingOrder",
	"Just generate the leading order cross section",
	0);
	static SwitchOption interfaceContributionPositiveNLO
	(interfaceContribution,
	"PositiveNLO",
	"Generate the positive contribution to the full NLO cross section",
	1);
	static SwitchOption interfaceContributionNegativeNLO
	(interfaceContribution,
	"NegativeNLO",
	"Generate the negative contribution to the full NLO cross section",
	2);

	static Switch<MEPP2ZHPowheg,unsigned int> interfaceNLOalphaSopt
	("NLOalphaSopt",
	"Whether to use a fixed or a running QCD coupling for the NLO weight",
	&MEPP2ZHPowheg::_nlo_alphaS_opt, 0, false, false);
	static SwitchOption interfaceNLOalphaSoptRunningAlphaS
	(interfaceNLOalphaSopt,
	"RunningAlphaS",
	"Use the usual running QCD coupling evaluated at scale scale()",
	0);
	static SwitchOption interfaceNLOalphaSoptFixedAlphaS
	(interfaceNLOalphaSopt,
	"FixedAlphaS",
	"Use a constant QCD coupling for comparison/debugging purposes",
	1);

	static Parameter<MEPP2ZHPowheg,double> interfaceFixedNLOalphaS
	("FixedNLOalphaS",
	"The value of alphaS to use for the nlo weight if _nlo_alphaS_opt=1",
	&MEPP2ZHPowheg::_fixed_alphaS, 0.115895, 0., 1.0,
	false, false, Interface::limited);

	static Parameter<MEPP2ZHPowheg,double> interfaceCorrectionCoefficient
	("CorrectionCoefficient",
	"The magnitude of the correction term to reduce the negative contribution",
	&MEPP2ZHPowheg::_a, 0.5, -10., 10.0,
	false, false, Interface::limited);

	static Parameter<MEPP2ZHPowheg,double> interfaceCorrectionPower
	("CorrectionPower",
	"The power of the correction term to reduce the negative contribution",
	&MEPP2ZHPowheg::_p, 0.7, 0.0, 1.0,
	false, false, Interface::limited);

	static Switch<MEPP2ZHPowheg,unsigned int> interfaceFactorizationScaleOption
	("FactorizationScaleOption",
	"Option for the scale to be used",
	&MEPP2ZHPowheg::_scaleopt, 1, false, false);
	static SwitchOption interfaceScaleOptionFixed
	(interfaceFactorizationScaleOption,
	"Fixed",
	"Use a fixed scale",
	0);
	static SwitchOption interfaceScaleOptionsHat
	(interfaceFactorizationScaleOption,
	"Dynamic",
	"Use the mass of the vector boson-Higgs boson system",
	1);

	static Parameter<MEPP2ZHPowheg,Energy> interfaceFactorizationScaleValue
	("FactorizationScaleValue",
	"The fixed scale to use if required",
	&MEPP2ZHPowheg::_fixedScale, GeV, 100.0GeV, 10.0GeV, 1000.0*GeV,
	false, false, Interface::limited);

	static Parameter<MEPP2ZHPowheg,double> interfaceScaleFactor
	("ScaleFactor",
	"The factor used before sHat if using a running scale",
	&MEPP2ZHPowheg::_scaleFact, 1.0, 0.0, 10.0,
	false, false, Interface::limited);

	}

	void MEPP2ZHPowheg::doinit() {
	// gluon ParticleData object
	_gluon = getParticleData(ParticleID::g);
	MEPP2ZH::doinit();
	}

	Energy2 MEPP2ZHPowheg::scale() const {
	return _scaleopt == 0 ? sqr(_fixedScale) : _scaleFact*sHat();
	}

	int MEPP2ZHPowheg::nDim() const {
	return 7;
	}

	bool MEPP2ZHPowheg::generateKinematics(const double * r) {
	_xt=*(r+5);
	_v =*(r+6);
	return MEPP2ZH::generateKinematics(r);
	}

	CrossSection MEPP2ZHPowheg::dSigHatDR() const {
	// Get Born momentum fractions xbar_a and xbar_b:
	_xb_a = lastX1();
	_xb_b = lastX2();
	return MEPP2ZH::dSigHatDR()*NLOweight();
	}

	double MEPP2ZHPowheg::NLOweight() const {
	// If only leading order is required return 1:
	if(_contrib==0) return 1.;
	useMe();
	// Get particle data for QCD particles:
	_parton_a=mePartonData()[0];
	_parton_b=mePartonData()[1];
	// get BeamParticleData objects for PDF's
	_hadron_A=dynamic_ptr_cast<Ptr<BeamParticleData>::transient_const_pointer>
	(lastParticles().first->dataPtr());
	_hadron_B=dynamic_ptr_cast<Ptr<BeamParticleData>::transient_const_pointer>
	(lastParticles().second->dataPtr());
	// If necessary swap the particle data vectors so that _xb_a,
	// mePartonData[0], beam[0] relate to the inbound quark:
	if(!(lastPartons().first ->dataPtr()==_parton_a&&
	lastPartons().second->dataPtr()==_parton_b)) {
	swap(_xb_a ,_xb_b);
	swap(_hadron_A,_hadron_B);
	}
	// calculate the PDF's for the Born process
	_oldq = _hadron_A->pdf()->xfx(_hadron_A,_parton_a,scale(),_xb_a)/_xb_a;
	_oldqbar = _hadron_B->pdf()->xfx(_hadron_B,_parton_b,scale(),_xb_b)/_xb_b;
	// Calculate alpha_S
	_alphaS2Pi = _nlo_alphaS_opt==1 ? _fixed_alphaS : SM().alphaS(scale());
	_alphaS2Pi /= 2.*Constants::pi;
	// Calculate the invariant mass of the dilepton pair
	_mll2 = sHat();
	_mu2 = scale();
	// Calculate the integrand
	// q qbar contribution
	double wqqvirt = Vtilde_qq();
	double wqqcollin = Ctilde_qq(x(_xt,1.),1.) + Ctilde_qq(x(_xt,0.),0.);
	double wqqreal = Ftilde_qq(_xt,_v);
	double wqq = wqqvirt+wqqcollin+wqqreal;
	// q g contribution
	double wqgcollin = Ctilde_qg(x(_xt,0.),0.);
	double wqgreal = Ftilde_qg(_xt,_v);
	double wqg = wqgreal+wqgcollin;
	// g qbar contribution
	double wgqbarcollin = Ctilde_gq(x(_xt,1.),1.);
	double wgqbarreal = Ftilde_gq(_xt,_v);
	double wgqbar = wgqbarreal+wgqbarcollin;
	// total
	double wgt = 1.+(wqq+wqg+wgqbar);
	// KMH - 06/08 - This seems to give wrong NLO results for
	// associated Higgs so I'm omitting it.
	// //trick to try and reduce neg wgt contribution
	// if(_xt<1.-_eps)
	// wgt += _a*(1./pow(1.-_xt,_p)-(1.-pow(_eps,1.-_p))/(1.-_p)/(1.-_eps));
	// return the answer
	assert(!isinf(wgt)&&!isnan(wgt));
	return _contrib==1 ? max(0.,wgt) : max(0.,-wgt);
	}

	double MEPP2ZHPowheg::x(double xt, double v) const {
	double x0(xbar(v));
	return x0+(1.-x0)*xt;
	}

	double MEPP2ZHPowheg::x_a(double x, double v) const {
	if(x==1.) return _xb_a;
	if(v==0.) return _xb_a;
	if(v==1.) return _xb_a/x;
	return (_xb_a/sqrt(x))sqrt((1.-(1.-x)(1.-v))/(1.-(1.-x)*v));
	}

	double MEPP2ZHPowheg::x_b(double x, double v) const {
	if(x==1.) return _xb_b;
	if(v==0.) return _xb_b/x;
	if(v==1.) return _xb_b;
	return (_xb_b/sqrt(x))sqrt((1.-(1.-x)v)/(1.-(1.-x)*(1.-v)));
	}

	double MEPP2ZHPowheg::xbar(double v) const {
	double xba2(sqr(_xb_a)), xbb2(sqr(_xb_b)), omv(-999.);
	double xbar1(-999.), xbar2(-999.);
	if(v==1.) return _xb_a;
	if(v==0.) return _xb_b;
	omv = 1.-v;
	xbar1=4.* v*xba2/
	(sqrt(sqr(1.+xba2)4.sqr(omv)+16.(1.-2.omv)xba2)+2.omv(1.-_xb_a)(1.+_xb_a));
	xbar2=4.omvxbb2/
	(sqrt(sqr(1.+xbb2)4.sqr( v)+16.(1.-2. v)xbb2)+2. v(1.-_xb_b)(1.+_xb_b));
	return max(xbar1,xbar2);
	}

	double MEPP2ZHPowheg::Ltilde_qq(double x, double v) const {
	if(x==1.) return 1.;
	double xa(x_a(x,v)),xb(x_b(x,v));
	double newq = (_hadron_A->pdf()->xfx(_hadron_A,_parton_a,scale(), xa)/ xa);
	double newqbar = (_hadron_B->pdf()->xfx(_hadron_B,_parton_b,scale(), xb)/ xb);
	return( newq * newqbar / _oldq / _oldqbar );
	}

	double MEPP2ZHPowheg::Ltilde_qg(double x, double v) const {
	double xa(x_a(x,v)),xb(x_b(x,v));
	double newq = (_hadron_A->pdf()->xfx(_hadron_A,_parton_a,scale(), xa)/ xa);
	double newg2 = (_hadron_B->pdf()->xfx(_hadron_B,_gluon ,scale(), xb)/ xb);
	return( newq * newg2 / _oldq / _oldqbar );
	}

	double MEPP2ZHPowheg::Ltilde_gq(double x, double v) const {
	double xa(x_a(x,v)),xb(x_b(x,v));
	double newg1 = (_hadron_A->pdf()->xfx(_hadron_A,_gluon ,scale(), xa)/ xa);
	double newqbar = (_hadron_B->pdf()->xfx(_hadron_B,_parton_b,scale(), xb)/ xb);
	return( newg1 * newqbar / _oldq / _oldqbar );
	}

	double MEPP2ZHPowheg::Vtilde_qq() const {
	return _alphaS2PiCF_(-3.log(_mu2/_mll2)+(2.sqr(Constants::pi)/3.)-8.);
	}

	double MEPP2ZHPowheg::Ccalbar_qg(double x) const {
	return (sqr(x)+sqr(1.-x))(log(_mll2/(_mu2x))+2.log(1.-x))+2.x*(1.-x);
	}

	double MEPP2ZHPowheg::Ctilde_qg(double x, double v) const {
	return _alphaS2PiTR_ ((1.-xbar(v))/x) * Ccalbar_qg(x)*Ltilde_qg(x,v);
	}

	double MEPP2ZHPowheg::Ctilde_gq(double x, double v) const {
	return _alphaS2PiTR_ ((1.-xbar(v))/x) * Ccalbar_qg(x)*Ltilde_gq(x,v);
	}

	double MEPP2ZHPowheg::Ctilde_qq(double x, double v) const {
	double wgt
	= ((1.-x)/x+(1.+xx)/(1.-x)/x(2.log(1.-x)-log(x)))Ltilde_qq(x,v)
	- 4.*log(1.-x)/(1.-x)
	+ 2./(1.-xbar(v))log(1.-xbar(v))log(1.-xbar(v))
	+ (2./(1.-xbar(v))log(1.-xbar(v))-2./(1.-x)+(1.+xx)/x/(1.-x)*Ltilde_qq(x,v))
	*log(_mll2/_mu2);
	return _alphaS2PiCF_(1.-xbar(v))*wgt;
	}

	double MEPP2ZHPowheg::Fcal_qq(double x, double v) const {
	return (sqr(1.-x)(1.-2.v(1.-v))+2.x)/x*Ltilde_qq(x,v);
	}

	double MEPP2ZHPowheg::Fcal_qg(double x, double v) const {
	return ((1.-xbar(v))/x)*
	(2.x(1.-x)v+sqr((1.-x)v)+sqr(x)+sqr(1.-x))*Ltilde_qg(x,v);
	}

	double MEPP2ZHPowheg::Fcal_gq(double x, double v) const {
	return ((1.-xbar(v))/x)*
	(2.x(1.-x)(1.-v)+sqr((1.-x)(1.-v))+sqr(x)+sqr(1.-x))*Ltilde_gq(x,v);
	}

	double MEPP2ZHPowheg::Ftilde_qg(double xt, double v) const {
	return _alphaS2PiTR_
	( Fcal_qg(x(xt,v),v) - Fcal_qg(x(xt,0.),0.) )/v;
	}

	double MEPP2ZHPowheg::Ftilde_gq(double xt, double v) const {
	return _alphaS2PiTR_
	( Fcal_gq(x(xt,v),v) - Fcal_gq(x(xt,1.),1.) )/(1.-v);
	}

	double MEPP2ZHPowheg::Ftilde_qq(double xt, double v) const {
	double eps(1e-10);
	// is emission into regular or singular region?
	if(xt>=0. && xt<1.-eps && v>eps && v<1.-eps) {
	// x<1, v>0, v<1 (regular emission, neither soft or collinear):
	return _alphaS2PiCF_
	(( ( Fcal_qq(x(xt, v), v) - Fcal_qq(x(xt,1.),1.) ) / (1.-v)+
	( Fcal_qq(x(xt, v), v) - Fcal_qq(x(xt,0.),0.) ) / v )/(1.-xt)
	+ ( log(1.-xbar(v)) - log(1.-_xb_a))*2./(1.-v)
	+ ( log(1.-xbar(v)) - log(1.-_xb_b))*2./v);
	}
	else {
	// make sure emission is actually in the allowed phase space:
	if(!(v>=0. && v<=1. && xt>=0. && xt<=1.)) {
	ostringstream s;
	s << "MEPP2ZHPowheg::Ftilde_qq : \n" << "xt(" << xt << ") and / or v("
	<< v << ") not in the phase space.";
	generator()->logWarning(Exception(s.str(),Exception::warning));
	return 0.;
	}
	// is emission soft singular?
	if(xt>=1.-eps) {
	// x=1:
	if(v<=eps) {
	// x==1, v=0 (soft and collinear with particle b):
	return _alphaS2PiCF_
	( ( log(1.-xbar(v)) - log(1.-_xb_a))*2./(1.-v)
	);
	} else if(v>=1.-eps) {
	// x==1, v=1 (soft and collinear with particle a):
	return _alphaS2PiCF_
	( ( log(1.-xbar(v)) - log(1.-_xb_b))*2./v
	);
	} else {
	// x==1, 0<v<1 (soft wide angle emission):
	return _alphaS2PiCF_
	( ( log(1.-xbar(v)) - log(1.-_xb_a))*2./(1.-v)
	+ ( log(1.-xbar(v)) - log(1.-_xb_b))*2./v
	);
	}
	} else {
	// x<1:
	if(v<=eps) {
	// x<1 but v=0 (collinear with particle b, but not soft):
	return _alphaS2PiCF_
	( ( ( Fcal_qq(x(xt, v), v) - Fcal_qq(x(xt,1.),1.) ) / (1.-v)
	)/(1.-xt)
	+ ( log(1.-xbar(v)) - log(1.-_xb_a))*2./(1.-v)
	);
	} else if(v>=1.-eps) {
	// x<1 but v=1 (collinear with particle a, but not soft):
	return _alphaS2PiCF_
	( ( ( Fcal_qq(x(xt, v), v) - Fcal_qq(x(xt,0.),0.) ) / v
	)/(1.-xt)
	+ ( log(1.-xbar(v)) - log(1.-_xb_b))*2./v
	);
	}
	}
	}
	return 0.;
	}
	diff --git a/MatrixElement/Powheg/VVKinematics.h b/MatrixElement/Powheg/VVKinematics.h
	--- a/MatrixElement/Powheg/VVKinematics.h
	+++ b/MatrixElement/Powheg/VVKinematics.h
	@@ -1,436 +1,684 @@
	// -- C++ --
	#ifndef HERWIG_VVKinematics_H
	#define HERWIG_VVKinematics_H
	//
	// This is the declaration of the VVKinematics class.
	//

	#include "ThePEG/Vectors/Lorentz5Vector.h"

	namespace Herwig {
	using namespace ThePEG;

	/** \ingroup VVKinematics
	* The bornVVKinematics class is used to store information on the
	* the kinematics of the real emission processes needed for the
	* evaluation of matrix elements in the real part of the NLO process.
	*/
	class bornVVKinematics {

	public:

	/**
	* Default constructor
	*/
	bornVVKinematics();

	/**
	* Meaningful constructor: takes the momenta
	* and Bjorken x values of the partons involved
	* in the 2->2 scattering of the leading order
	* / virtual process and calculates all interesting
	* Mandelstam and Born variables.
	*/
	bornVVKinematics(vector<Lorentz5Momentum> Momenta, double x1, double x2);

	public:

	/**
	* Read-only access to all of the above member variables.
	*/

	/**
	* @name Leading order momentum fractions and associated etabar's:
	*/
	//@{
	/**
	* Leading order momentum fraction for first particle
	*/
	double x1b() const { return x1b_; }

	/**
	* Leading order etabar for first particle
	*/
	double eta1b() const { return eta1b_; }

	/**
	* Leading order momentum fraction for second particle
	*/
	double x2b() const { return x2b_; }

	/**
	* Leading order etabar for second particle
	*/
	double eta2b() const { return eta2b_; }
	//@}

	/**
	* @name The Born momenta according to the notation of the FMNR papers,
	* in the diboson centre of mass frame:
	*/
	//@{
	/**
	* Momentum \f$p_1\f$
	*/
	Lorentz5Momentum p1b() const { return p1b_; }

	/**
	* Momentum \f$p_2\f$
	*/
	Lorentz5Momentum p2b() const { return p2b_; }

	/**
	* Momentum \f$k_1\f$
	*/
	Lorentz5Momentum k1b() const { return k1b_; }

	/**
	* Momentum \f$k_2\f$
	*/
	Lorentz5Momentum k2b() const { return k2b_; }
	//@}

	/**
	* @name The diboson invariant mass / shat, that and uhat:
	*/
	//@{
	/**
	* \f$\hat s\f$
	*/
	Energy2 sb() const { return sb_; }

	/**
	* \f$\hat t\f$
	*/
	Energy2 tb() const { return tb_; }

	/**
	* \f$\hat u\f$
	*/
	Energy2 ub() const { return ub_; }
	//@}

	/**
	* The diboson rapidity:
	* Note Yb_ = + lastY() if flipped = false
	* but Yb_ = - lastY() if flipped = true.
	* Yb_ is always defined with the quark travelling in the +z direction!
	*/
	double Yb() const { return Yb_; }

	/**
	* @name Masses of the final state bosons:
	*/
	//@{
	/**
	* Mass squared og the first boson
	*/
	Energy2 k12b() const { return k12b_; }

	/**
	* Mass squared og the second boson
	*/
	Energy2 k22b() const { return k22b_; }
	//@}

	/**
	* Polar and azimuthal angles of the dibosons in their rest frame:
	*/
	double theta1b() const { return theta1b_; }

	/**
	* A check to make sure that the momenta calculated from
	* the energies and angles are equal to those of meMomenta().
	*/
	void sanityCheck() const;

	private:

	/**
	* Invariants required for the evaluation of 2-> 2 next-to-leading
	* order quantities (Frixione et al. NPB.383 WZ production at colliders).
	*/

	/**
	* @name Leading order momentum fractions and associated etabar's:
	*/
	//@{
	/**
	* Leading order momentum fraction for first particle
	*/
	double x1b_;

	/**
	* Leading order etabar for first particle
	*/
	double eta1b_;

	/**
	* Leading order momentum fraction for second particle
	*/
	double x2b_;

	/**
	* Leading order etabar for second particle
	*/
	double eta2b_;
	//@}

	/**
	* @name The Born momenta according to the notation of the FMNR papers,
	* in the diboson centre of mass frame:
	*/
	//@{
	/**
	* Momentum \f$p_1\f$
	*/
	Lorentz5Momentum p1b_;

	/**
	* Momentum \f$p_2\f$
	*/
	Lorentz5Momentum p2b_;

	/**
	* Momentum \f$k_1\f$
	*/
	Lorentz5Momentum k1b_;

	/**
	* Momentum \f$k_2\f$
	*/
	Lorentz5Momentum k2b_;
	//@}

	/**
	* @name The diboson invariant mass / shat, that and uhat:
	*/
	//@{
	/**
	* \f$\hat s\f$
	*/
	Energy2 sb_;

	/**
	* \f$\hat t\f$
	*/
	Energy2 tb_;

	/**
	* \f$\hat u\f$
	*/
	Energy2 ub_;
	//@}

	/**
	* The diboson rapidity:
	* Note Yb_ = + lastY() if flipped = false
	* but Yb_ = - lastY() if flipped = true.
	* Yb_ is always defined with the quark travelling in the +z direction!
	*/
	double Yb_;

	/**
	* @name Masses of the final state bosons:
	*/
	//@{
	/**
	* Mass squared og the first boson
	*/
	Energy2 k12b_;

	/**
	* Mass squared og the second boson
	*/
	Energy2 k22b_;
	//@}

	/**
	* Polar angle of the dibosons in their rest frame:
	*/
	double theta1b_;
	};



	/** \ingroup VVKinematics
	* The realVVKinematics class is used to store information on the
	* the kinematics of the real emission processes needed for the
	* evaluation of matrix elements in the real part of the NLO process.
	*/
	class realVVKinematics {

	public:

	/**
	* Default constructor
	*/
	realVVKinematics();

	/**
	* Meaningful constructor: takes the Born variables
	* from the leading order /virtual 2->2 process and
	* the raw \f$\tilde{x}, y\f$ radiative variables and turns
	* these into a set of 2->3 momenta with associated
	* Mandelstam variables, Bjorken x values etc.
	+ * @param bornVariables The object for the Born kinematics
	* @param xt The \f$\tilde{x}\f$ radiative variable.
	* @param y The angular radiative variable (the cosine
	- * of the polar angle of the emitted gluon in the partonic
	+ * of the polar angle of the emitted gluon in the partonic
	+ * @param theta2 The angle \f$\theta_2\f$
	* CMS frame).
	*/
	realVVKinematics(bornVVKinematics bornVariables,double xt, double y, double theta2);

	/**
	* A check to make sure that the momenta calculated from
	* the energies and angles are equal to those of meMomenta().
	*/
	void sanityCheck() const;

	public:

	/**
	* Read-only access to all of the above member variables.
	*/

	/**
	* The bornVVKinematics underlying the 2->3 kinematics
	*/
	bornVVKinematics bornVariables() const { return bornVariables_; }

	/**
	* The lower bound on the x integration:
	*/
	double xbar() const { return xbar_; }

	/**
	* @name The `raw' radiative variables.
	*/
	//@{
	/**
	* The \f$\tilde{x}\f$ radiative variable
	*/
	double xt() const { return xt_; }

	/**
	* The \f$y\f$ radiative variable
	*/
	double y() const { return y_; }

	/**
	* The \f$x_r\f$ radiative variable
	*/
	double xr() const { return xr_; }
	//@}

	/**
	* The momentum fraction of the parton incident from the +z direction.
	*/
	double x1r() const { return x1r_; }

	/**
	* The momentum fraction of the parton incident from the -z direction.
	*/
	double x2r() const { return x2r_; }

	/**
	* Invariants required for the evaluation of next-to-leading order
	* quantities (Frixione et al. NPB.383 WZ production at colliders).
	*/

	- // First the Born variables:
	+ /**
	+ * @name First the Born variables:
	+ */
	+ //@{
	+ /**
	+ * \f$s_2\f$ variable from Frixione et al. NPB.383,3
	+ */
	Energy2 s2r() const { return s2r_; }
	+
	+ /**
	+ * \f$k_1^2\f$ mass of first vector boson
	+ */
	Energy2 k12r() const { return k12r_; }
	+
	+ /**
	+ * \f$k_2^2\f$ mass of second vector boson
	+ */
	Energy2 k22r() const { return k22r_; }
	+
	+ /**
	+ * \f$\theta_1\f$ angle from Frixione et al. NPB.383,3
	+ */
	double theta1r() const { return theta1r_; }
	+
	+ /**
	+ * \f$\theta_2\f$ angle from Frixione et al. NPB.383,3
	+ */
	double theta2r() const { return theta2r_; }
	+ //@}

	- // Then the rest:
	+ /**
	+ * @name Then the rest:
	+ */
	+ //@{
	+ /**
	+ * \f$p_T^2\f$ in the lab frame
	+ */
	Energy2 pT2_in_lab() const { return tkr_*ukr_/sr_; }
	+
	+ /**
	+ * \f$s\f$ from Frixione et al. NPB.383,3
	+ */
	Energy2 sr() const { return sr_; }
	+
	+ /**
	+ * \f$t_k\f$ from Frixione et al. NPB.383,3
	+ */
	Energy2 tkr() const { return tkr_; }
	+
	+ /**
	+ * \f$u_k\f$ from Frixione et al. NPB.383,3
	+ */
	Energy2 ukr() const { return ukr_; }
	+
	+ /**
	+ * \f$\cos\psi\f$ from Frixione et al. NPB.383,3
	+ */
	double cpsir() const { return cpsir_; }
	+
	+ /**
	+ * \f$\cos\psi'\f$ from Frixione et al. NPB.383,3
	+ */
	double cpsipr() const { return cpsiprr_; }
	+
	+ /**
	+ * \f$\beta_x\f$ from Frixione et al. NPB.383,3
	+ */
	double betaxr() const { return betaxr_; }
	+
	+ /**
	+ * \f$v_1\f$ variable from Frixione et al. NPB.383,3
	+ */
	double v1r() const { return v1r_; }
	+
	+ /**
	+ * \f$v_2\f$ variable from Frixione et al. NPB.383,3
	+ */
	double v2r() const { return v2r_; }
	+
	+ /**
	+ * \f$q_1\f$ variable from Frixione et al. NPB.383,3
	+ */
	Energy2 q1r() const { return q1r_; }
	+
	+ /**
	+ * \f$q_2\f$ variable from Frixione et al. NPB.383,3
	+ */
	Energy2 q2r() const { return q2r_; }
	+
	+ /**
	+ * \f$\hat q_1\f$ variable from Frixione et al. NPB.383,3
	+ */
	Energy2 q1hatr() const { return q1hatr_; }
	+
	+ /**
	+ * \f$\hat q_2\f$ variable from Frixione et al. NPB.383,3
	+ */
	Energy2 q2hatr() const { return q2hatr_; }
	+
	+ /**
	+ * \f$\hat w_1\f$ variable from Frixione et al. NPB.383,3
	+ */
	Energy2 w1r() const { return w1r_; }
	+
	+ /**
	+ * \f$\hat w_2\f$ variable from Frixione et al. NPB.383,3
	+ */
	Energy2 w2r() const { return w2r_; }
	+
	+ /**
	+ * 4-momentum \f$p_1\f$ from Frixione et al. NPB.383,3
	+ */
	Lorentz5Momentum p1r() const { return p1r_; }
	+
	+ /**
	+ * 4-momentum \f$p_2\f$ from Frixione et al. NPB.383,3
	+ */
	Lorentz5Momentum p2r() const { return p2r_; }
	+
	+ /**
	+ * 4-momentum \f$k\f$ from Frixione et al. NPB.383,3
	+ */
	Lorentz5Momentum kr() const { return kr_ ; }
	+
	+ /**
	+ * 4-momentum \f$k_1\f$ from Frixione et al. NPB.383,3
	+ */
	Lorentz5Momentum k1r() const { return k1r_; }
	+
	+ /**
	+ * 4-momentum \f$k_2\f$ from Frixione et al. NPB.383,3
	+ */
	Lorentz5Momentum k2r() const { return k2r_; }
	+
	+ /**
	+ * Set 4-momentum \f$p_1\f$ from Frixione et al. NPB.383,3
	+ */
	void p1r(Lorentz5Momentum p1r) { p1r_ = p1r; }
	+
	+ /**
	+ * Set 4-momentum \f$p_2\f$ from Frixione et al. NPB.383,3
	+ */
	void p2r(Lorentz5Momentum p2r) { p2r_ = p2r; }
	+
	+ /**
	+ * Set 4-momentum \f$k\f$ from Frixione et al. NPB.383,3
	+ */
	void kr (Lorentz5Momentum kr ) { kr_ = kr ; }
	+
	+ /**
	+ * Set 4-momentum \f$k_1\f$ from Frixione et al. NPB.383,3
	+ */
	void k1r(Lorentz5Momentum k1r) { k1r_ = k1r; }
	+
	+ /**
	+ * Set 4-momentum \f$k_2\f$ from Frixione et al. NPB.383,3
	+ */
	void k2r(Lorentz5Momentum k2r) { k2r_ = k2r; }
	-
	+ //@}

	private:
	+
	/**
	* The bornVVKinematics object underlying the 2->3 kinematics.
	*/
	bornVVKinematics bornVariables_;

	/**
	* The lower bound on the x integration.
	*/
	double xbar_;

	// The `raw' radiative variables.
	+ /**
	+ * @name The `raw' radiative variables.
	+ */
	+ //@{
	+ /**
	+ * The \f$\tilde{x}\f$ radiative variable
	+ */
	double xt_;
	+
	+ /**
	+ * The \f$y\f$ radiative variable
	+ */
	double y_;
	+
	+ /**
	+ * The \f$x_r\f$ radiative variable
	+ */
	double xr_;
	+ //@}

	/**
	* The momentum fraction of the parton incident from the +z direction.
	*/
	double x1r_;

	/**
	* The momentum fraction of the parton incident from the -z direction.
	*/
	double x2r_;

	/**
	* Invariants required for the evaluation of next-to-leading order
	* quantities (Frixione et al. NPB.383 WZ production at colliders).
	*/
	- // First the Born variables:
	+
	+ /**
	+ * @name First the Born variables:
	+ */
	+ //@{
	+ /**
	+ * \f$s_2\f$ variable from Frixione et al. NPB.383,3
	+ */
	Energy2 s2r_;
	+
	+ /**
	+ * \f$k_1^2\f$ mass of first vector boson
	+ */
	Energy2 k12r_;
	+
	+ /**
	+ * \f$k_2^2\f$ mass of second vector boson
	+ */
	Energy2 k22r_;
	+
	+ /**
	+ * \f$\theta_1\f$ angle from Frixione et al. NPB.383,3
	+ */
	double theta1r_;
	+
	+ /**
	+ * \f$\theta_2\f$ angle from Frixione et al. NPB.383,3
	+ */
	double theta2r_;
	- // Then the rest:
	+ //@}
	+
	+ /**
	+ * @name Then the rest:
	+ */
	+ //@{
	+ /**
	+ * \f$s\f$ from Frixione et al. NPB.383,3
	+ */
	Energy2 sr_;
	+
	+ /**
	+ * \f$t_k\f$ from Frixione et al. NPB.383,3
	+ */
	Energy2 tkr_;
	+
	+ /**
	+ * \f$u_k\f$ from Frixione et al. NPB.383,3
	+ */
	Energy2 ukr_;
	+
	+ /**
	+ * \f$\cos\psi\f$ from Frixione et al. NPB.383,3
	+ */
	double cpsir_;
	+
	+ /**
	+ * \f$\cos\psi'\f$ from Frixione et al. NPB.383,3
	+ */
	double cpsiprr_;
	+
	+ /**
	+ * \f$\beta_x\f$ from Frixione et al. NPB.383,3
	+ */
	double betaxr_;
	+
	+ /**
	+ * \f$v_1\f$ variable from Frixione et al. NPB.383,3
	+ */
	double v1r_;
	+
	+ /**
	+ * \f$v_2\f$ variable from Frixione et al. NPB.383,3
	+ */
	double v2r_;
	+
	+ /**
	+ * \f$q_1\f$ variable from Frixione et al. NPB.383,3
	+ */
	Energy2 q1r_;
	+
	+ /**
	+ * \f$q_2\f$ variable from Frixione et al. NPB.383,3
	+ */
	Energy2 q2r_;
	+
	+ /**
	+ * \f$\hat q_1\f$ variable from Frixione et al. NPB.383,3
	+ */
	Energy2 q1hatr_;
	+
	+ /**
	+ * \f$\hat q_2\f$ variable from Frixione et al. NPB.383,3
	+ */
	Energy2 q2hatr_;
	+
	+ /**
	+ * \f$\hat w_1\f$ variable from Frixione et al. NPB.383,3
	+ */
	Energy2 w1r_;
	+
	+ /**
	+ * \f$\hat w_2\f$ variable from Frixione et al. NPB.383,3
	+ */
	Energy2 w2r_;
	+
	+ /**
	+ * 4-momentum \f$p_1\f$ from Frixione et al. NPB.383,3
	+ */
	Lorentz5Momentum p1r_;
	+
	+ /**
	+ * 4-momentum \f$p_2\f$ from Frixione et al. NPB.383,3
	+ */
	Lorentz5Momentum p2r_;
	+
	+ /**
	+ * 4-momentum \f$k\f$ from Frixione et al. NPB.383,3
	+ */
	Lorentz5Momentum kr_;
	+
	+ /**
	+ * 4-momentum \f$k_1\f$ from Frixione et al. NPB.383,3
	+ */
	Lorentz5Momentum k1r_;
	+
	+ /**
	+ * 4-momentum \f$k_2\f$ from Frixione et al. NPB.383,3
	+ */
	Lorentz5Momentum k2r_;
	+ //@}

	};

	}

	#endif /* HERWIG_VVKinematics_H */

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