No OneTemporary
Actions

Size

56 KB

Subscribers

None

View Options

	diff --git a/MatrixElement/DIS/DISBase.cc b/MatrixElement/DIS/DISBase.cc
	--- a/MatrixElement/DIS/DISBase.cc
	+++ b/MatrixElement/DIS/DISBase.cc
	@@ -1,1305 +1,1176 @@
	// -- C++ --
	//
	// This is the implementation of the non-inlined, non-templated member
	// functions of the DISBase class.
	//

	#include "DISBase.h"
	#include "ThePEG/Interface/ClassDocumentation.h"
	#include "ThePEG/Interface/Switch.h"
	#include "ThePEG/Interface/Reference.h"
	#include "ThePEG/Interface/Parameter.h"
	#include "ThePEG/Persistency/PersistentOStream.h"
	#include "ThePEG/Persistency/PersistentIStream.h"
	#include "ThePEG/PDT/EnumParticles.h"
	#include "ThePEG/MatrixElement/Tree2toNDiagram.h"
	#include "Herwig/Utilities/Maths.h"
	#include "ThePEG/PDT/EnumParticles.h"
	#include "ThePEG/PDT/StandardMatchers.h"
	#include "ThePEG/Repository/EventGenerator.h"
	#include "ThePEG/Repository/CurrentGenerator.h"
	#include "ThePEG/Helicity/Vertex/AbstractFFVVertex.h"
	#include "Herwig/PDT/StandardMatchers.h"
	#include "Herwig/Models/StandardModel/StandardModel.h"
	#include <numeric>
	#include "Herwig/Shower/RealEmissionProcess.h"
	#include "Herwig/Shower/QTilde/Base/ShowerProgenitor.h"
	#include "Herwig/Shower/QTilde/Base/Branching.h"

	using namespace Herwig;
	using namespace ThePEG::Helicity;

	// namespace {
	// using namespace Herwig;
	// using namespace ThePEG::Helicity;
	//
	// void debuggingMatrixElement(bool BGF,const Lorentz5Momentum & pin,
	// const Lorentz5Momentum & p1,
	// const Lorentz5Momentum & p2,
	// tcPDPtr gluon,
	// const Lorentz5Momentum & pl1,
	// const Lorentz5Momentum & pl2,
	// const Lorentz5Momentum & pq1,
	// const Lorentz5Momentum & pq2,
	// tcPDPtr lepton1,tcPDPtr lepton2,
	// tcPDPtr quark1 ,tcPDPtr quark2,
	// Energy2 Q2,double phi, double x2, double x3,
	// double xperp, double zp, double xp,
	// const vector<double> & azicoeff,
	// bool normalize) {
	// tcHwSMPtr hwsm=ThePEG::dynamic_ptr_cast<tcHwSMPtr>
	// (CurrentGenerator::current().standardModel());
	// assert(hwsm);
	// vector<AbstractFFVVertexPtr> weakVertex;
	// vector<PDPtr> bosons;
	// AbstractFFVVertexPtr strongVertex = hwsm->vertexFFG();
	// if(lepton1->id()==lepton2->id()) {
	// weakVertex.push_back(hwsm->vertexFFZ());
	// bosons.push_back(hwsm->getParticleData(ParticleID::Z0));
	// weakVertex.push_back(hwsm->vertexFFP());
	// bosons.push_back(hwsm->getParticleData(ParticleID::gamma));
	// }
	// else {
	// weakVertex.push_back(hwsm->vertexFFW());
	// bosons.push_back(hwsm->getParticleData(ParticleID::Wplus));
	// }
	// if(!BGF) {
	// SpinorWaveFunction l1,q1,qp1;
	// SpinorBarWaveFunction l2,q2,qp2;
	// VectorWaveFunction gl(p2,gluon,outgoing);
	// if(lepton1->id()>0) {
	// l1 = SpinorWaveFunction (pl1,lepton1,incoming);
	// l2 = SpinorBarWaveFunction(pl2,lepton2,outgoing);
	// }
	// else {
	// l1 = SpinorWaveFunction (pl2,lepton2,outgoing);
	// l2 = SpinorBarWaveFunction(pl1,lepton1,incoming);
	// }
	// if(quark1->id()>0) {
	// q1 = SpinorWaveFunction (pq1,quark1,incoming);
	// q2 = SpinorBarWaveFunction(pq2,quark2,outgoing);
	// qp1 = SpinorWaveFunction (pin,quark1,incoming);
	// qp2 = SpinorBarWaveFunction(p1 ,quark2,outgoing);
	// }
	// else {
	// q1 = SpinorWaveFunction (pq2,quark2,outgoing);
	// q2 = SpinorBarWaveFunction(pq1,quark1,incoming);
	// qp1 = SpinorWaveFunction (p1 ,quark2,outgoing);
	// qp2 = SpinorBarWaveFunction(pin,quark1,incoming);
	// }
	// double lome(0.),realme(0.);
	// for(unsigned int lhel1=0;lhel1<2;++lhel1) {
	// l1.reset(lhel1);
	// for(unsigned int lhel2=0;lhel2<2;++lhel2) {
	// l2.reset(lhel2);
	// for(unsigned int qhel1=0;qhel1<2;++qhel1) {
	// q1.reset(qhel1);
	// qp1.reset(qhel1);
	// for(unsigned int qhel2=0;qhel2<2;++qhel2) {
	// q2.reset(qhel2);
	// qp2.reset(qhel2);
	// // leading order matrix element
	// Complex diagLO(0.);
	// for(unsigned int ix=0;ix<weakVertex.size();++ix) {
	// VectorWaveFunction inter =
	// weakVertex[ix]->evaluate(Q2,3,bosons[ix],l1,l2);
	// diagLO += weakVertex[ix]->evaluate(Q2,q1,q2,inter);
	// }
	// lome += norm(diagLO);
	// // real emission matrix element
	// for(unsigned int ghel=0;ghel<2;++ghel) {
	// gl.reset(2*ghel);
	// Complex diagReal(0.);
	// for(unsigned int ix=0;ix<weakVertex.size();++ix) {
	// VectorWaveFunction inter =
	// weakVertex[ix]->evaluate(Q2,3,bosons[ix],l1,l2);
	// SpinorWaveFunction off1 =
	// strongVertex->evaluate(Q2,5,qp1.particle(),qp1,gl);
	// Complex diag1 = weakVertex[ix]->evaluate(Q2,off1,qp2,inter);
	// SpinorBarWaveFunction off2 =
	// strongVertex->evaluate(Q2,5,qp2.particle(),qp2,gl);
	// Complex diag2 = weakVertex[ix]->evaluate(Q2,qp1,off2,inter);
	// diagReal += diag1+diag2;
	// }
	// realme += norm(diagReal);
	// }
	// }
	// }
	// }
	// }
	// double test1 = realme/lome/hwsm->alphaS(Q2)Q2UnitRemoval::InvE2;
	// double cphi(cos(phi));
	// double test2;
	// if(normalize) {
	// test2 = 8.Constants::pi/(1.-xp)/(1.-zp)
	// (azicoeff[0]+azicoeff[1]cphi+azicoeff[2]sqr(cphi))*
	// (1.+sqr(xp)(sqr(x2)+1.5sqr(xperp)));
	// }
	// else {
	// test2 = 8.Constants::pi/(1.-xp)/(1.-zp)
	// (azicoeff[0]+azicoeff[1]cphi+azicoeff[2]sqr(cphi));
	// }
	// cerr << "testing RATIO A " << test1/test2 << "\n";
	// }
	// else {
	// SpinorWaveFunction l1,q1,qp1;
	// SpinorBarWaveFunction l2,q2,qp2;
	// VectorWaveFunction gl(pin,gluon,incoming);
	// if(lepton1->id()>0) {
	// l1 = SpinorWaveFunction (pl1,lepton1,incoming);
	// l2 = SpinorBarWaveFunction(pl2,lepton2,outgoing);
	// }
	// else {
	// l1 = SpinorWaveFunction (pl2,lepton2,outgoing);
	// l2 = SpinorBarWaveFunction(pl1,lepton1,incoming);
	// }
	// if(quark1->id()>0) {
	// q1 = SpinorWaveFunction (pq1,quark1 ,incoming);
	// q2 = SpinorBarWaveFunction(pq2,quark2 ,outgoing);
	// qp2 = SpinorBarWaveFunction(p1 ,quark2 ,outgoing);
	// qp1 = SpinorWaveFunction (p2 ,quark1->CC(),outgoing);
	// }
	// else {
	// q1 = SpinorWaveFunction (pq2,quark2 ,outgoing);
	// q2 = SpinorBarWaveFunction(pq1,quark1 ,incoming);
	// qp2 = SpinorBarWaveFunction(p2 ,quark1->CC(),outgoing);
	// qp1 = SpinorWaveFunction (p1 ,quark2 ,outgoing);
	// }
	// double lome(0.),realme(0.);
	// for(unsigned int lhel1=0;lhel1<2;++lhel1) {
	// l1.reset(lhel1);
	// for(unsigned int lhel2=0;lhel2<2;++lhel2) {
	// l2.reset(lhel2);
	// for(unsigned int qhel1=0;qhel1<2;++qhel1) {
	// q1.reset(qhel1);
	// qp1.reset(qhel1);
	// for(unsigned int qhel2=0;qhel2<2;++qhel2) {
	// q2.reset(qhel2);
	// qp2.reset(qhel2);
	// // leading order matrix element
	// Complex diagLO(0.);
	// for(unsigned int ix=0;ix<weakVertex.size();++ix) {
	// VectorWaveFunction inter =
	// weakVertex[ix]->evaluate(Q2,3,bosons[ix],l1,l2);
	// diagLO += weakVertex[ix]->evaluate(Q2,q1,q2,inter);
	// }
	// lome += norm(diagLO);
	// // real emission matrix element
	// for(unsigned int ghel=0;ghel<2;++ghel) {
	// gl.reset(2*ghel);
	// Complex diagReal(0.);
	// for(unsigned int ix=0;ix<weakVertex.size();++ix) {
	// VectorWaveFunction inter =
	// weakVertex[ix]->evaluate(Q2,3,bosons[ix],l1,l2);
	// SpinorWaveFunction off1 =
	// strongVertex->evaluate(Q2,5,qp1.particle(),qp1,gl);
	// Complex diag1 = weakVertex[ix]->evaluate(Q2,off1,qp2,inter);
	// SpinorBarWaveFunction off2 =
	// strongVertex->evaluate(Q2,5,qp2.particle(),qp2,gl);
	// Complex diag2 = weakVertex[ix]->evaluate(Q2,qp1,off2,inter);
	// diagReal += diag1+diag2;
	// }
	// realme += norm(diagReal);
	// }
	// }
	// }
	// }
	// }
	// double test1 = realme/lome/hwsm->alphaS(Q2)Q2UnitRemoval::InvE2;
	// double cphi(cos(phi));
	// double test2;
	// if(normalize) {
	// test2 = 8.Constants::pi/zp/(1.-zp)
	// (azicoeff[0]+azicoeff[1]cphi+azicoeff[2]sqr(cphi))*
	// sqr(xp)(sqr(x3)+sqr(x2)+3.sqr(xperp));
	// }
	// else {
	// test2 = 8.Constants::pi/zp/(1.-zp)
	// (azicoeff[0]+azicoeff[1]cphi+azicoeff[2]sqr(cphi));
	// }
	// cerr << "testing RATIO B " << test1/test2 << "\n";
	// }
	// }
	//
	// }

	DISBase::DISBase() : initial_(6.), final_(3.),
	procProb_(0.35),
	comptonInt_(0.), bgfInt_(0.),
	comptonWeight_(50.), BGFWeight_(150.),
	pTmin_(0.1*GeV),
	scaleOpt_(1), muF_(100.*GeV), scaleFact_(1.),
	contrib_(0), power_(0.1)
	{}

	DISBase::~DISBase() {}

	void DISBase::persistentOutput(PersistentOStream & os) const {
	os << comptonInt_ << bgfInt_ << procProb_ << initial_ << final_ << alpha_
	<< ounit(pTmin_,GeV) << comptonWeight_ << BGFWeight_ << gluon_
	<< ounit(muF_,GeV) << scaleFact_ << scaleOpt_ << contrib_<< power_;
	}

	void DISBase::persistentInput(PersistentIStream & is, int) {
	is >> comptonInt_ >> bgfInt_ >> procProb_ >> initial_ >> final_ >> alpha_
	>> iunit(pTmin_,GeV) >> comptonWeight_ >> BGFWeight_ >> gluon_
	>> iunit(muF_,GeV) >> scaleFact_ >> scaleOpt_ >> contrib_ >> power_;
	}

	AbstractClassDescription<DISBase> DISBase::initDISBase;
	// Definition of the static class description member.

	void DISBase::Init() {

	static ClassDocumentation<DISBase> documentation
	("The DISBase class provides the base class for the "
	"implementation of DIS type processes including the "
	"hard corrections in either the old-fashioned matrix "
	"element correction of POWHEG approaches");

	static Parameter<DISBase,double> interfaceProcessProbability
	("ProcessProbability",
	"The probabilty of the QCD compton process for the process selection",
	&DISBase::procProb_, 0.3, 0.0, 1.,
	false, false, Interface::limited);

	static Reference<DISBase,ShowerAlpha> interfaceCoupling
	("Coupling",
	"Pointer to the object to calculate the coupling for the correction",
	&DISBase::alpha_, false, false, true, false, false);

	static Parameter<DISBase,Energy> interfacepTMin
	("pTMin",
	"The minimum pT",
	&DISBase::pTmin_, GeV, 1.GeV, 0.0GeV, 10.0*GeV,
	false, false, Interface::limited);

	static Parameter<DISBase,double> interfaceComptonWeight
	("ComptonWeight",
	"Weight for the overestimate ofthe compton channel",
	&DISBase::comptonWeight_, 50.0, 0.0, 100.0,
	false, false, Interface::limited);

	static Parameter<DISBase,double> interfaceBGFWeight
	("BGFWeight",
	"Weight for the overestimate of the BGF channel",
	&DISBase::BGFWeight_, 100.0, 0.0, 1000.0,
	false, false, Interface::limited);

	static Switch<DISBase,unsigned int> interfaceContribution
	("Contribution",
	"Which contributions to the cross section to include",
	&DISBase::contrib_, 0, 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<DISBase,unsigned int> interfaceScaleOption
	("ScaleOption",
	"Option for the choice of factorization (and renormalization) scale",
	&DISBase::scaleOpt_, 1, false, false);
	static SwitchOption interfaceDynamic
	(interfaceScaleOption,
	"Dynamic",
	"Dynamic factorization scale equal to the current sqrt(sHat())",
	1);
	static SwitchOption interfaceFixed
	(interfaceScaleOption,
	"Fixed",
	"Use a fixed factorization scale set with FactorizationScaleValue",
	2);

	static Parameter<DISBase,Energy> interfaceFactorizationScale
	("FactorizationScale",
	"Value to use in the event of a fixed factorization scale",
	&DISBase::muF_, GeV, 100.0GeV, 1.0GeV, 500.0*GeV,
	true, false, Interface::limited);

	static Parameter<DISBase,double> interfaceScaleFactor
	("ScaleFactor",
	"The factor used before Q2 if using a running scale",
	&DISBase::scaleFact_, 1.0, 0.0, 10.0,
	false, false, Interface::limited);

	static Parameter<DISBase,double> interfaceSamplingPower
	("SamplingPower",
	"Power for the sampling of xp",
	&DISBase::power_, 0.6, 0.0, 1.,
	false, false, Interface::limited);
	}

	void DISBase::doinit() {
	HwMEBase::doinit();
	// integrals of me over phase space
	double r5=sqrt(5.),darg((r5-1.)/(r5+1.)),ath(0.5*log((1.+1./r5)/(1.-1./r5)));
	comptonInt_ = 2.(-21./20.-6./(5.r5)*ath+sqr(Constants::pi)/3.
	-2.Math::ReLi2(1.-darg)-2.Math::ReLi2(1.-1./darg));
	bgfInt_ = 121./9.-56./r5*ath;
	// extract the gluon ParticleData objects
	gluon_ = getParticleData(ParticleID::g);
	}

	void DISBase::initializeMECorrection(RealEmissionProcessPtr born, double & initial,
	double & final) {
	initial = initial_;
	final = final_;
	// incoming particles
	for(unsigned int ix=0;ix<born->bornIncoming().size();++ix) {
	if(QuarkMatcher::Check(born->bornIncoming()[ix]->data())) {
	partons_[0] = born->bornIncoming()[ix]->dataPtr();
	pq_[0] = born->bornIncoming()[ix]->momentum();
	}
	else if(LeptonMatcher::Check(born->bornIncoming()[ix]->data())) {
	leptons_[0] = born->bornIncoming()[ix]->dataPtr();
	pl_[0] = born->bornIncoming()[ix]->momentum();
	}
	}
	// outgoing particles
	for(unsigned int ix=0;ix<born->bornOutgoing().size();++ix) {
	if(QuarkMatcher::Check(born->bornOutgoing()[ix]->data())) {
	partons_[1] = born->bornOutgoing()[ix]->dataPtr();
	pq_[1] = born->bornOutgoing()[ix]->momentum();
	}
	else if(LeptonMatcher::Check(born->bornOutgoing()[ix]->data())) {
	leptons_[1] = born->bornOutgoing()[ix]->dataPtr();
	pl_[1] = born->bornOutgoing()[ix]->momentum();
	}
	}
	// extract the born variables
	q_ =pl_[0]-pl_[1];
	q2_ = -q_.m2();
	double yB = (q_pq_[0])/(pl_[0]pq_[0]);
	l_ = 2./yB-1.;
	// calculate the A coefficient for the correlations
	acoeff_ = A(leptons_[0],leptons_[1],
	partons_[0],partons_[1],q2_);
	}

	RealEmissionProcessPtr DISBase::applyHardMatrixElementCorrection(RealEmissionProcessPtr born) {
	static const double eps=1e-6;
	// find the incoming and outgoing quarks and leptons
	PPtr quark[2],lepton[2];
	PPtr hadron;
	unsigned int iqIn(0),iqOut(0);
	// incoming particles
	for(unsigned int ix=0;ix<born->bornIncoming().size();++ix) {
	if(QuarkMatcher::Check(born->bornIncoming()[ix]->data())) {
	iqIn=ix;
	quark[0] = born->bornIncoming()[ix];
	hadron = born->hadrons()[ix];
	beam_ = dynamic_ptr_cast<tcBeamPtr>(hadron->dataPtr());
	xB_ = quark[0]->momentum().rho()/hadron->momentum().rho();
	}
	else if(LeptonMatcher::Check(born->bornIncoming()[ix]->data())) {
	lepton[0] = born->bornIncoming()[ix];
	}
	}
	pdf_ = beam_->pdf();
	assert(beam_&&pdf_&&quark[0]&&lepton[0]);
	// outgoing particles
	for(unsigned int ix=0;ix<born->bornOutgoing().size();++ix) {
	if(QuarkMatcher::Check(born->bornOutgoing()[ix]->data())) {
	iqOut=ix;
	quark [1] = born->bornOutgoing()[ix];
	}
	else if(LeptonMatcher::Check(born->bornOutgoing()[ix]->data())) {
	lepton[1] = born->bornOutgoing()[ix];
	}
	}
	// momentum fraction
	assert(quark[1]&&lepton[1]);
	// calculate the matrix element
	vector<double> azicoeff;
	// select the type of process
	bool BGF = UseRandom::rnd()>procProb_;
	double xp,zp,wgt,x1,x2,x3,xperp;
	// generate a QCD compton process
	if(!BGF) {
	wgt = generateComptonPoint(xp,zp);
	if(xp<eps) return RealEmissionProcessPtr();
	// common pieces
	Energy2 scale = q2_((1.-xp)(1-zp)*zp/xp+1.);
	wgt = 2./3./Constants::pialpha_->value(scale)/procProb_;
	// PDF piece
	wgt *= pdf_->xfx(beam_,quark[0]->dataPtr(),scale,xB_/xp)/
	pdf_->xfx(beam_,quark[0]->dataPtr(),q2_ ,xB_);
	// other bits
	xperp = sqrt(4.(1.-xp)(1.-zp)*zp/xp);
	x1 = -1./xp;
	x2 = 1.-(1.-zp)/xp;
	x3 = 2.+x1-x2;
	// matrix element pieces
	azicoeff = ComptonME(xp,x2,xperp,true);
	}
	// generate a BGF process
	else {
	wgt = generateBGFPoint(xp,zp);
	if(xp<eps) return RealEmissionProcessPtr();
	// common pieces
	Energy2 scale = q2_((1.-xp)(1-zp)*zp/xp+1);
	wgt = 0.25/Constants::pialpha_->value(scale)/(1.-procProb_);
	// PDF piece
	wgt *= pdf_->xfx(beam_,gluon_ ,scale,xB_/xp)/
	pdf_->xfx(beam_,quark[0]->dataPtr(),q2_ ,xB_);
	// other bits
	xperp = sqrt(4.(1.-xp)(1.-zp)*zp/xp);
	x1 = -1./xp;
	x2 = 1.-(1.-zp)/xp;
	x3 = 2.+x1-x2;
	// matrix element pieces
	azicoeff = BGFME(xp,x2,x3,xperp,true);
	}
	// compute the azimuthal average of the weight
	wgt = (azicoeff[0]+0.5azicoeff[2]);
	// decide whether or not to accept the weight
	if(UseRandom::rnd()>wgt) return RealEmissionProcessPtr();
	// if generate generate phi
	unsigned int itry(0);
	double phimax = std::accumulate(azicoeff.begin(),azicoeff.end(),0.);
	double phiwgt,phi;
	do {
	phi = UseRandom::rnd()*Constants::twopi;
	double cphi(cos(phi));
	phiwgt = azicoeff[0]+azicoeff[1]cphi+azicoeff[2]sqr(cphi);
	++itry;
	}
	while (phimax*UseRandom::rnd() > phiwgt && itry<200);
	if(itry==200) throw Exception() << "Too many tries in DISMECorrection"
	<< "::applyHardMatrixElementCorrection() to"
	<< " generate phi" << Exception::eventerror;
	// construct lorentz transform from lab to breit frame
	Lorentz5Momentum phadron = hadron->momentum();
	phadron.setMass(0.*GeV);
	phadron.rescaleEnergy();
	Lorentz5Momentum pcmf = phadron+0.5/xB_*q_;
	pcmf.rescaleMass();
	LorentzRotation rot(-pcmf.boostVector());
	Lorentz5Momentum pbeam = rot*phadron;
	Axis axis(pbeam.vect().unit());
	double sinth(sqrt(sqr(axis.x())+sqr(axis.y())));
	rot.rotate(-acos(axis.z()),Axis(-axis.y()/sinth,axis.x()/sinth,0.));
	Lorentz5Momentum pl = rot*pl_[0];
	rot.rotateZ(-atan2(pl.y(),pl.x()));
	pl_[0] *= rot;
	pl_[1] *= rot;
	pq_[0] *= rot;
	pq_[1] *= rot;
	// compute the new incoming and outgoing momenta
	Energy Q(sqrt(q2_));
	Lorentz5Momentum p1 = Lorentz5Momentum( 0.5Qxperpcos(phi), 0.5Qxperpsin(phi),
	-0.5Qx2,0.GeV,0.GeV);
	p1.rescaleEnergy();
	Lorentz5Momentum p2 = Lorentz5Momentum(-0.5Qxperpcos(phi),-0.5Qxperpsin(phi),
	-0.5Qx3,0.GeV,0.GeV);
	p2.rescaleEnergy();
	Lorentz5Momentum pin(0.GeV,0.GeV,-0.5x1Q,-0.5x1Q,0.*GeV);
	// debuggingMatrixElement(BGF,pin,p1,p2,gluon_,pl_[0],pl_[1],pq_[0],pq_[1],
	// lepton[0]->dataPtr(),lepton[1]->dataPtr(),
	// quark [0]->dataPtr(),quark [1]->dataPtr(),
	// q2_,phi,x2,x3,xperp,zp,xp,azicoeff,true);
	// we need the Lorentz transform back to the lab
	rot.invert();
	// transform the momenta to lab frame
	pin *= rot;
	p1 *= rot;
	p2 *= rot;
	// test to ensure outgoing particles can be put on-shell
	if(!BGF) {
	if(p1.e()<quark[1]->dataPtr()->constituentMass()) return RealEmissionProcessPtr();
	if(p2.e()<gluon_ ->constituentMass()) return RealEmissionProcessPtr();
	}
	else {
	if(p1.e()<quark[1]->dataPtr() ->constituentMass()) return RealEmissionProcessPtr();
	if(p2.e()<quark[0]->dataPtr()->CC()->constituentMass()) return RealEmissionProcessPtr();
	}
	// create the new particles and real emission process
	bool isQuark = quark[0]->colourLine();
	bool FSR = false;
	// incoming lepton if first
	if(iqIn==1)
	born->incoming().push_back(born->bornIncoming()[0]->dataPtr()->
	produceParticle(born->bornIncoming()[0]->momentum()));
	// outgoing lepton if first
	if(iqOut==1)
	born->outgoing().push_back(born->bornOutgoing()[0]->dataPtr()->
	produceParticle(born->bornOutgoing()[0]->momentum()));
	PPtr newin,newout,emitted;
	// radiating system
	if(!BGF) {
	newin = quark[0]->dataPtr()->produceParticle(pin);
	emitted = gluon_ ->produceParticle(p2 );
	newout = quark[1]->dataPtr()->produceParticle(p1 );
	emitted->incomingColour(newin,!isQuark);
	emitted->colourConnect(newout,!isQuark);
	FSR = xp>zp;
	}
	else {
	newin = gluon_ ->produceParticle(pin);
	emitted = quark[0]->dataPtr()->CC()->produceParticle(p2 );
	newout = quark[1]->dataPtr() ->produceParticle(p1 );
	emitted->incomingColour(newin, isQuark);
	newout ->incomingColour(newin,!isQuark);
	FSR = false;
	}
	// set x
	double x(xB_/xp);
	if(born->incoming().size()==0)
	born->x(make_pair(x,1.));
	else
	born->x(make_pair(1.,x));
	if(FSR) {
	born->emitter(born->outgoing().size()+2);
	born->spectator(born->incoming().size());
	}
	else {
	born->emitter(born->incoming().size());
	born->spectator(born->outgoing().size()+2);
	}
	born->emitted(4);
	// radiating particles
	born->incoming().push_back(newin );
	born->outgoing().push_back(newout);
	// incoming lepton if second
	if(iqIn==0)
	born->incoming().push_back(born->bornIncoming()[1]->dataPtr()->
	produceParticle(born->bornIncoming()[1]->momentum()));
	// outgoing lepton if second
	if(iqOut==0)
	born->outgoing().push_back(born->bornOutgoing()[1]->dataPtr()->
	produceParticle(born->bornOutgoing()[1]->momentum()));
	// radiated particle
	born->outgoing().push_back(emitted);
	return born;
	}

	bool DISBase::softMatrixElementVeto(ShowerProgenitorPtr initial,
	ShowerParticlePtr parent, Branching br) {
	bool veto = !UseRandom::rndbool(parent->isFinalState() ? 1./final_ : 1./initial_);
	// check if me correction should be applied
	long id[2]={initial->id(),parent->id()};
	if(id[0]!=id[1]\|\|id[1]==ParticleID::g) return veto;
	// get the pT
	Energy pT=br.kinematics->pT();
	// check if hardest so far
	if(pT<initial->highestpT()) return veto;
	double kappa(sqr(br.kinematics->scale())/q2_),z(br.kinematics->z());
	double zk((1.-z)*kappa);
	// final-state
	double wgt(0.);
	if(parent->isFinalState()) {
	double zp=z,xp=1./(1.+z*zk);
	double xperp = sqrt(4.(1.-xp)(1.-zp)*zp/xp);
	double x2 = 1.-(1.-zp)/xp;
	vector<double> azicoeff = ComptonME(xp,x2,xperp,false);
	wgt = (azicoeff[0]+0.5azicoeff[2])xp/(1.+sqr(z))/final_;
	if(wgt<.0\|\|wgt>1.) {
	ostringstream wstring;
	wstring << "Soft ME correction weight too large or "
	<< "negative for FSR in DISBase::"
	<< "softMatrixElementVeto() soft weight "
	<< " xp = " << xp << " zp = " << zp
	<< " weight = " << wgt << "\n";
	generator()->logWarning( Exception(wstring.str(),
	Exception::warning) );
	}
	}
	else {
	double xp = 2.z/(1.+zk+sqrt(sqr(1.+zk)-4.z*zk));
	double zp = 0.5* (1.-zk+sqrt(sqr(1.+zk)-4.zzk));
	double xperp = sqrt(4.(1.-xp)(1.-zp)*zp/xp);
	double x1 = -1./xp, x2 = 1.-(1.-zp)/xp, x3 = 2.+x1-x2;
	// compton
	if(br.ids[0]->id()!=ParticleID::g) {
	vector<double> azicoeff = ComptonME(xp,x2,xperp,false);
	wgt = (azicoeff[0]+0.5azicoeff[2])xp*(1.-z)/(1.-xp)/(1.+sqr(z))/
	(1.-zp+xp-2.xp(1.-zp));
	}
	// BGF
	else {
	vector<double> azicoeff = BGFME(xp,x2,x3,xperp,true);
	wgt = (azicoeff[0]+0.5azicoeff[2])xp/(1.-zp+xp-2.xp(1.-zp))/(sqr(z)+sqr(1.-z));
	}
	wgt /=initial_;
	if(wgt<.0\|\|wgt>1.) {
	ostringstream wstring;
	wstring << "Soft ME correction weight too large or "
	<< "negative for ISR in DISBase::"
	<< "softMatrixElementVeto() soft weight "
	<< " xp = " << xp << " zp = " << zp
	<< " weight = " << wgt << "\n";
	generator()->logWarning( Exception(wstring.str(),
	Exception::warning) );
	}
	}
	// if not vetoed
	if(UseRandom::rndbool(wgt)) return false;
	// otherwise
	parent->vetoEmission(br.type,br.kinematics->scale());
	return true;
	}

	double DISBase::generateComptonPoint(double &xp, double & zp) {
	static const double maxwgt = 1.;
	double wgt;
	do {
	xp = UseRandom::rnd();
	double zpmin = xp, zpmax = 1./(1.+xp*(1.-xp));
	zp = 1.-pow((1.-zpmin)/(1.-zpmax),UseRandom::rnd())*(1.-zpmax);
	wgt = log((1.-zpmin)/(1.-zpmax))*(1.-zp);
	if(UseRandom::rndbool()) swap(xp,zp);
	double xperp2 = 4.(1.-xp)(1.-zp)*zp/xp,x2=1.-(1.-zp)/xp;
	wgt = 2.(1.+sqr(xp)(sqr(x2)+1.5xperp2))/(1.-xp)/(1.-zp);
	if(wgt>maxwgt) {
	ostringstream wstring;
	wstring << "DISBase::generateComptonPoint "
	<< "Weight greater than maximum "
	<< "wgt = " << wgt << " maxwgt = 1\n";
	generator()->logWarning( Exception(wstring.str(),
	Exception::warning) );
	}
	}
	while(wgt<UseRandom::rnd()*maxwgt);
	return comptonInt_;
	}

	double DISBase::generateBGFPoint(double &xp, double & zp) {
	static const double maxwgt = 25.;
	double wgt;
	do {
	xp = UseRandom::rnd();
	double zpmax = 1./(1.+xp*(1.-xp)), zpmin = 1.-zpmax;
	zp = 1.-pow((1.-zpmin)/(1.-zpmax),UseRandom::rnd())*(1.-zpmax);
	wgt = log((1.-zpmin)/(1.-zpmax))*(1.-zp);
	double x1 = -1./xp;
	double x2 = 1.-(1.-zp)/xp;
	double x3 = 2.+x1-x2;
	double xperp2 = 4.(1.-xp)(1.-zp)*zp/xp;
	wgt = sqr(xp)/(1.-zp)(sqr(x3)+sqr(x2)+3.*xperp2);
	if(wgt>maxwgt) {
	ostringstream wstring;
	wstring << "DISBase::generateBGFPoint "
	<< "Weight greater than maximum "
	<< "wgt = " << wgt << " maxwgt = 1\n";
	generator()->logWarning( Exception(wstring.str(),
	Exception::warning) );
	}
	}
	while(wgt<UseRandom::rnd()*maxwgt);
	return bgfInt_;
	// static const double maxwgt = 2.,npow=0.34,ac=1.0;
	// double wgt;
	// do {
	// double rho = UseRandom::rnd();
	// xp = 1.-pow(rho,1./(1.-npow));
	// wgt = (sqr(xp)+ac+sqr(1.-xp));
	// if(wgt>1.+ac) cerr << "testing violates BGF maxA " << wgt << "\n";
	// }
	// while(wgt<UseRandom::rnd()*(1.+ac));
	// double xpwgt = -((6.-5.npow+sqr(npow))ac-3.*npow+sqr(npow)+4)
	// /(sqr(npow)(npow-6.)+11.npow-6.);
	// xpwgt *= pow(1.-xp,npow)/wgt;
	// double xp2(sqr(xp)),lxp(log(xp)),xp4(sqr(xp2)),lxp1(log(1.-xp));
	// double zpwgt = (2.xp4(lxp+lxp1-3.)+4.xpxp2*(3.-lxp-lxp1)
	// +xp2(-13.+lxp+lxp1)+xp(+7.+lxp+lxp1)-lxp-lxp1-1.)/(1.+xp-xp2);
	// do {
	// double zpmax = 1./(1.+xp*(1.-xp)), zpmin = 1.-zpmax;
	// zp = 1.-pow((1.-zpmin)/(1.-zpmax),UseRandom::rnd())*(1.-zpmax);
	// wgt = log((1.-zpmin)/(1.-zpmax))*(1.-zp);
	// double x1 = -1./xp;
	// double x2 = 1.-(1.-zp)/xp;
	// double x3 = 2.+x1-x2;
	// double xperp2 = 4.(1.-xp)(1.-zp)*zp/xp;
	// wgt = sqr(xp)/(1.-zp)(sqr(x3)+sqr(x2)+3.*xperp2);
	// if(wgt>maxwgt*zpwgt) cerr << "testing violates BGF maxB " << wgt/xpwgt << "\n";
	// }
	// while(wgt<UseRandom::rnd()*maxwgt);
	// return zpwgt*xpwgt;
	}

	vector<double> DISBase::ComptonME(double xp, double x2, double xperp,
	bool norm) {
	vector<double> output(3,0.);
	double cos2 = x2 /sqrt(sqr(x2)+sqr(xperp));
	double sin2 = xperp/sqrt(sqr(x2)+sqr(xperp));
	double root = sqrt(sqr(l_)-1.);
	output[0] = sqr(cos2)+acoeff_cos2l_+sqr(l_);
	output[1] = -acoeff_cos2rootsin2-2.l_rootsin2;
	output[2] = sqr(root)*sqr(sin2);
	double lo(1+acoeff_*l_+sqr(l_));
	double denom = norm ? 1.+sqr(xp)(sqr(x2)+1.5sqr(xperp)) : 1.;
	double fact = sqr(xp)*(sqr(x2)+sqr(xperp))/lo;
	for(unsigned int ix=0;ix<output.size();++ix)
	output[ix] = ((ix==0 ? 1. : 0.) +fact*output[ix])/denom;
	return output;
	}

	vector<double> DISBase::BGFME(double xp, double x2, double x3,
	double xperp, bool norm) {
	vector<double> output(3,0.);
	double cos2 = x2 /sqrt(sqr(x2)+sqr(xperp));
	double sin2 = xperp/sqrt(sqr(x2)+sqr(xperp));
	double fact2 = sqr(xp)*(sqr(x2)+sqr(xperp));
	double cos3 = x3 /sqrt(sqr(x3)+sqr(xperp));
	double sin3 = xperp/sqrt(sqr(x3)+sqr(xperp));
	double fact3 = sqr(xp)*(sqr(x3)+sqr(xperp));
	double root = sqrt(sqr(l_)-1.);
	output[0] = fact2(sqr(cos2)+acoeff_cos2*l_+sqr(l_)) +
	fact3(sqr(cos3)-acoeff_cos3*l_+sqr(l_));
	output[1] = - fact2(acoeff_cos2rootsin2+2.l_root*sin2)
	- fact3(acoeff_cos3rootsin3-2.l_root*sin3);
	output[2] = fact2(sqr(root)sqr(sin2)) +
	fact3(sqr(root)sqr(sin3));
	double lo(1+acoeff_*l_+sqr(l_));
	double denom = norm ? sqr(xp)(sqr(x3)+sqr(x2)+3.sqr(xperp))*lo : lo;
	for(unsigned int ix=0;ix<output.size();++ix) output[ix] /= denom;
	return output;
	}

	-RealEmissionProcessPtr DISBase::generateHardest(RealEmissionProcessPtr tree,
	+RealEmissionProcessPtr DISBase::generateHardest(RealEmissionProcessPtr born,
	ShowerInteraction::Type inter) {
	- assert(false);
	- return RealEmissionProcessPtr();
	-// // check if generating QCD radiation
	-// if(inter==ShowerInteraction::QED) return HardTreePtr();
	-// ShowerParticlePtr quark[2],lepton[2];
	-// PPtr hadron;
	-// // incoming particles
	-// for(map<ShowerProgenitorPtr,ShowerParticlePtr>::const_iterator
	-// cit=tree->incomingLines().begin();cit!=tree->incomingLines().end();++cit) {
	-// if(QuarkMatcher::Check(cit->first->progenitor()->data())) {
	-// hadron = cit->first->original()->parents()[0];
	-// quark [0] = cit->first->progenitor();
	-// beam_ = cit->first->beam();
	-// }
	-// else if(LeptonMatcher::Check(cit->first->progenitor()->data())) {
	-// lepton[0] = cit->first->progenitor();
	-// leptons_[0] = lepton[0]->dataPtr();
	-// }
	-// }
	-// pdf_=beam_->pdf();
	-// assert(beam_&&pdf_&&quark[0]&&lepton[0]);
	-// // outgoing particles
	-// for(map<ShowerProgenitorPtr,tShowerParticlePtr>::const_iterator
	-// cit=tree->outgoingLines().begin();cit!=tree->outgoingLines().end();++cit) {
	-// if(QuarkMatcher::Check(cit->first->progenitor()->data()))
	-// quark [1] = cit->first->progenitor();
	-// else if(LeptonMatcher::Check(cit->first->progenitor()->data())) {
	-// lepton[1] = cit->first->progenitor();
	-// leptons_[1] = lepton[1]->dataPtr();
	-// }
	-// }
	-// assert(quark[1]&&lepton[1]);
	-// // Particle data objects
	-// for(unsigned int ix=0;ix<2;++ix) partons_[ix] = quark[ix]->dataPtr();
	-// // extract the born variables
	-// q_ =lepton[0]->momentum()-lepton[1]->momentum();
	-// q2_ = -q_.m2();
	-// xB_ = quark[0]->x();
	-// double yB =
	-// ( q_*quark[0]->momentum())/
	-// (lepton[0]->momentum()*quark[0]->momentum());
	-// l_ = 2./yB-1.;
	-// // construct lorentz transform from lab to breit frame
	-// Lorentz5Momentum phadron = hadron->momentum();
	-// phadron.setMass(0.*GeV);
	-// phadron.rescaleRho();
	-// Lorentz5Momentum pb = quark[0]->momentum();
	-// Axis axis(q_.vect().unit());
	-// double sinth(sqrt(sqr(axis.x())+sqr(axis.y())));
	-// LorentzRotation rot_ = LorentzRotation();
	-// if(axis.perp2()>1e-20) {
	-// rot_.setRotate(-acos(axis.z()),Axis(-axis.y()/sinth,axis.x()/sinth,0.));
	-// rot_.rotateX(Constants::pi);
	-// }
	-// if(abs(1.-q_.e()/q_.vect().mag())>1e-6) rot_.boostZ( q_.e()/q_.vect().mag());
	-// pb *= rot_;
	-// if(pb.perp2()/GeV2>1e-20) {
	-// Boost trans = -1./pb.e()*pb.vect();
	-// trans.setZ(0.);
	-// rot_.boost(trans);
	-// }
	-// Lorentz5Momentum pl = rot_*lepton[0]->momentum();
	-// rot_.rotateZ(-atan2(pl.y(),pl.x()));
	-// // momenta of the particles
	-// pl_[0]=rot_*lepton[0]->momentum();
	-// pl_[1]=rot_*lepton[1]->momentum();
	-// pq_[0]=rot_* quark[0]->momentum();
	-// pq_[1]=rot_* quark[1]->momentum();
	-// q_ *= rot_;
	-// // coefficient for the matrix elements
	-// acoeff_ = A(lepton[0]->dataPtr(),lepton[1]->dataPtr(),
	-// quark [0]->dataPtr(),quark [1]->dataPtr(),q2_);
	-// // generate a compton point
	-// generateCompton();
	-// generateBGF();
	-// // no valid emission, return
	-// if(pTCompton_<ZERO&&pTBGF_<ZERO) return HardTreePtr();
	-// // type of emission, pick highest pT
	-// bool isCompton=pTCompton_>pTBGF_;
	-// // // find the sudakov for the branching
	-// // SudakovPtr sudakov;
	-// // // ISR
	-// // if(ComptonISFS_\|\|!isCompton) {
	-// // BranchingList branchings=evolver()->splittingGenerator()->initialStateBranchings();
	-// // long index = abs(partons_[0]->id());
	-// // IdList br(3);
	-// // if(isCompton) {
	-// // br[0] = index;
	-// // br[1] = index;
	-// // br[2] = ParticleID::g;
	-// // }
	-// // else {
	-// // br[0] = ParticleID::g;
	-// // br[1] = abs(partons_[0]->id());
	-// // br[2] = -abs(partons_[0]->id());
	-// // }
	-// // for(BranchingList::const_iterator cit = branchings.lower_bound(index);
	-// // cit != branchings.upper_bound(index); ++cit ) {
	-// // IdList ids = cit->second.second;
	-// // if(ids[0]==br[0]&&ids[1]==br[1]&&ids[2]==br[2]) {
	-// // sudakov=cit->second.first;
	-// // break;
	-// // }
	-// // }
	-// // }
	-// // // FSR
	-// // else {
	-// // BranchingList branchings =
	-// // evolver()->splittingGenerator()->finalStateBranchings();
	-// // long index=abs(partons_[1]->id());
	-// // for(BranchingList::const_iterator cit = branchings.lower_bound(index);
	-// // cit != branchings.upper_bound(index); ++cit ) {
	-// // IdList ids = cit->second.second;
	-// // if(ids[0]==index&&ids[1]==index&&ids[2]==ParticleID::g) {
	-// // sudakov = cit->second.first;
	-// // break;
	-// // }
	-// // }
	-// // }
	-// // if(!sudakov) throw Exception() << "Can't find Sudakov for the hard emission in "
	-// // << "DISBase::generateHardest()"
	-// // << Exception::runerror;
	-// // add the leptons
	-// vector<HardBranchingPtr> spaceBranchings,allBranchings;
	-// spaceBranchings.push_back(new_ptr(HardBranching(lepton[0],SudakovPtr(),
	-// HardBranchingPtr(),
	-// HardBranching::Incoming)));
	-// allBranchings.push_back(spaceBranchings.back());
	-// allBranchings.push_back(new_ptr(HardBranching(lepton[1],SudakovPtr(),
	-// HardBranchingPtr(),
	-// HardBranching::Outgoing)));
	-// // compton hardest
	-// if(isCompton) {
	-// rot_.invert();
	-// for(unsigned int ix=0;ix<ComptonMomenta_.size();++ix) {
	-// ComptonMomenta_[ix].transform(rot_);
	-// }
	-// ShowerParticlePtr newqout (new_ptr(ShowerParticle(partons_[1],true)));
	-// newqout->set5Momentum(ComptonMomenta_[1]);
	-// ShowerParticlePtr newg(new_ptr(ShowerParticle(gluon_,true)));
	-// newg->set5Momentum(ComptonMomenta_[2]);
	-// ShowerParticlePtr newqin (new_ptr(ShowerParticle(partons_[0],false )));
	-// newqin->set5Momentum(ComptonMomenta_[0]);
	-// if(ComptonISFS_) {
	-// ShowerParticlePtr newspace(new_ptr(ShowerParticle(partons_[0],false)));
	-// newspace->set5Momentum(ComptonMomenta_[0]-ComptonMomenta_[2]);
	-// HardBranchingPtr spaceBranch(new_ptr(HardBranching(newqin,SudakovPtr(),
	-// HardBranchingPtr(),
	-// HardBranching::Incoming)));
	-// HardBranchingPtr offBranch(new_ptr(HardBranching(newspace,SudakovPtr(),
	-// spaceBranch,
	-// HardBranching::Incoming)));
	-// spaceBranch->addChild(offBranch);
	-// HardBranchingPtr g(new_ptr(HardBranching(newg,SudakovPtr(),spaceBranch,
	-// HardBranching::Outgoing)));
	-// spaceBranch->addChild(g);
	-// spaceBranch->type(offBranch->branchingParticle()->id()>0 ?
	-// ShowerPartnerType::QCDColourLine : ShowerPartnerType::QCDAntiColourLine);
	-// HardBranchingPtr outBranch(new_ptr(HardBranching(newqout,SudakovPtr(),
	-// HardBranchingPtr(),
	-// HardBranching::Outgoing)));
	-// spaceBranchings.push_back(spaceBranch);
	-// allBranchings.push_back(offBranch);
	-// allBranchings.push_back(outBranch);
	-// ColinePtr newin(new_ptr(ColourLine())),newout(new_ptr(ColourLine()));
	-// newin ->addColoured(newqin ,partons_[0]->id()<0);
	-// newin ->addColoured(newg ,partons_[0]->id()<0);
	-// newout->addColoured(newspace,partons_[0]->id()<0);
	-// newout->addColoured(newqout ,partons_[1]->id()<0);
	-// newout->addColoured(newg ,partons_[1]->id()>0);
	-// }
	-// else {
	-// ShowerParticlePtr newtime(new_ptr(ShowerParticle(partons_[1],true)));
	-// newtime->set5Momentum(ComptonMomenta_[1]+ComptonMomenta_[2]);
	-// HardBranchingPtr spaceBranch(new_ptr(HardBranching(newqin,SudakovPtr(),
	-// HardBranchingPtr(),
	-// HardBranching::Incoming)));
	-// HardBranchingPtr offBranch(new_ptr(HardBranching(newtime,SudakovPtr(),
	-// HardBranchingPtr(),
	-// HardBranching::Outgoing)));
	-// HardBranchingPtr g(new_ptr(HardBranching(newg,SudakovPtr(),offBranch,
	-// HardBranching::Outgoing)));
	-// HardBranchingPtr outBranch(new_ptr(HardBranching(newqout,SudakovPtr(),offBranch,
	-// HardBranching::Outgoing)));
	-// offBranch->addChild(outBranch);
	-// offBranch->addChild(g);
	-// offBranch->type(offBranch->branchingParticle()->id()>0 ?
	-// ShowerPartnerType::QCDColourLine : ShowerPartnerType::QCDAntiColourLine);
	-// spaceBranchings.push_back(spaceBranch);
	-// allBranchings.push_back(spaceBranch);
	-// allBranchings.push_back(offBranch);
	-// ColinePtr newin(new_ptr(ColourLine())),newout(new_ptr(ColourLine()));
	-// newin ->addColoured(newqin ,newqin->dataPtr()->iColour()!=PDT::Colour3);
	-// newin ->addColoured(newtime,newqin->dataPtr()->iColour()!=PDT::Colour3);
	-// newin ->addColoured(newg ,newqin->dataPtr()->iColour()!=PDT::Colour3);
	-// newout->addColoured(newg ,newqin->dataPtr()->iColour()==PDT::Colour3);
	-// newout->addColoured(newqout,newqin->dataPtr()->iColour()!=PDT::Colour3);
	-// }
	-// }
	-// // BGF hardest
	-// else {
	-// rot_.invert();
	-// for(unsigned int ix=0;ix<BGFMomenta_.size();++ix) {
	-// BGFMomenta_[ix].transform(rot_);
	-// }
	-// ShowerParticlePtr newq (new_ptr(ShowerParticle(partons_[1],true)));
	-// newq->set5Momentum(BGFMomenta_[1]);
	-// ShowerParticlePtr newqbar(new_ptr(ShowerParticle(partons_[0]->CC(),true)));
	-// newqbar->set5Momentum(BGFMomenta_[2]);
	-// ShowerParticlePtr newg (new_ptr(ShowerParticle(gluon_,false)));
	-// newg->set5Momentum(BGFMomenta_[0]);
	-// ShowerParticlePtr newspace(new_ptr(ShowerParticle(partons_[0],false)));
	-// newspace->set5Momentum(BGFMomenta_[0]-BGFMomenta_[2]);
	-// HardBranchingPtr spaceBranch(new_ptr(HardBranching(newg,SudakovPtr(),HardBranchingPtr(),
	-// HardBranching::Incoming)));
	-// HardBranchingPtr offBranch(new_ptr(HardBranching(newspace,SudakovPtr(),spaceBranch,
	-// HardBranching::Incoming)));
	-// HardBranchingPtr qbar(new_ptr(HardBranching(newqbar,SudakovPtr(),spaceBranch,
	-// HardBranching::Outgoing)));
	-// spaceBranch->addChild(offBranch);
	-// spaceBranch->addChild(qbar);
	-// spaceBranch->type(offBranch->branchingParticle()->id()>0 ?
	-// ShowerPartnerType::QCDColourLine : ShowerPartnerType::QCDAntiColourLine);
	-// HardBranchingPtr outBranch(new_ptr(HardBranching(newq,SudakovPtr(),
	-// HardBranchingPtr(),
	-// HardBranching::Outgoing)));
	-// spaceBranchings.push_back(spaceBranch);
	-// allBranchings.push_back(offBranch);
	-// allBranchings.push_back(outBranch);
	-// ColinePtr newin(new_ptr(ColourLine())),newout(new_ptr(ColourLine()));
	-// newout->addColoured(newspace,newspace->dataPtr()->iColour()!=PDT::Colour3);
	-// newout->addColoured(newq ,newspace->dataPtr()->iColour()!=PDT::Colour3);
	-// newout->addColoured(newg ,newspace->dataPtr()->iColour()!=PDT::Colour3);
	-// newin ->addColoured(newg ,newspace->dataPtr()->iColour()==PDT::Colour3);
	-// newin ->addColoured(newqbar ,newspace->dataPtr()->iColour()==PDT::Colour3);
	-// }
	-// allBranchings[2]->colourPartner(allBranchings[3]);
	-// allBranchings[3]->colourPartner(allBranchings[2]);
	-// HardTreePtr newTree(new_ptr(HardTree(allBranchings,spaceBranchings,
	-// ShowerInteraction::QCD)));
	-// // Set the maximum pt for all other emissions and connect hard and shower tree
	-// Energy pT = isCompton ? pTCompton_ : pTBGF_;
	-// // incoming particles
	-// for(map<ShowerProgenitorPtr,ShowerParticlePtr>::const_iterator
	-// cit=tree->incomingLines().begin();cit!=tree->incomingLines().end();++cit) {
	-// // set maximum pT
	-// if(QuarkMatcher::Check(cit->first->progenitor()->data()))
	-// cit->first->maximumpT(pT,ShowerInteraction::QCD);
	-// for(set<HardBranchingPtr>::iterator cjt=newTree->branchings().begin();
	-// cjt!=newTree->branchings().end();++cjt) {
	-// if(!(*cjt)->branchingParticle()->isFinalState()&&
	-// (*cjt)->branchingParticle()->id()==cit->first->progenitor()->id()) {
	-// newTree->connect(cit->first->progenitor(),*cjt);
	-// tPPtr beam =cit->first->original();
	-// if(!beam->parents().empty()) beam=beam->parents()[0];
	-// (*cjt)->beam(beam);
	-// HardBranchingPtr parent=(*cjt)->parent();
	-// while(parent) {
	-// parent->beam(beam);
	-// parent=parent->parent();
	-// };
	-// }
	-// }
	-// }
	-// // outgoing particles
	-// for(map<ShowerProgenitorPtr,tShowerParticlePtr>::const_iterator
	-// cit=tree->outgoingLines().begin();cit!=tree->outgoingLines().end();++cit) {
	-// // set maximum pT
	-// if(QuarkMatcher::Check(cit->first->progenitor()->data()))
	-// cit->first->maximumpT(pT,ShowerInteraction::QCD);
	-// for(set<HardBranchingPtr>::iterator cjt=newTree->branchings().begin();
	-// cjt!=newTree->branchings().end();++cjt) {
	-// if((*cjt)->branchingParticle()->isFinalState()&&
	-// (*cjt)->branchingParticle()->id()==cit->first->progenitor()->id()) {
	-// newTree->connect(cit->first->progenitor(),*cjt);
	-// }
	-// }
	-// }
	-// return newTree;
	+ // check if generating QCD radiation
	+ if(inter==ShowerInteraction::QED) return RealEmissionProcessPtr();
	+ PPtr quark[2],lepton[2];
	+ PPtr hadron;
	+ unsigned int iqIn(0),iqOut(0);
	+ // incoming particles
	+ for(unsigned int ix=0;ix<born->bornIncoming().size();++ix) {
	+ if(QuarkMatcher::Check(born->bornIncoming()[ix]->data())) {
	+ iqIn=ix;
	+ hadron = born->hadrons()[ix];
	+ quark [0] = born->bornIncoming()[ix];
	+ beam_ = dynamic_ptr_cast<tcBeamPtr>(hadron->dataPtr());
	+ xB_ = quark[0]->momentum().rho()/hadron->momentum().rho();
	+ }
	+ else if(LeptonMatcher::Check(born->bornIncoming()[ix]->data())) {
	+ lepton[0] = born->bornIncoming()[ix];
	+ leptons_[0] = lepton[0]->dataPtr();
	+ }
	+ }
	+ pdf_=beam_->pdf();
	+ assert(beam_&&pdf_&&quark[0]&&lepton[0]);
	+ // outgoing particles
	+ for(unsigned int ix=0;ix<born->bornOutgoing().size();++ix) {
	+ if(QuarkMatcher::Check(born->bornOutgoing()[ix]->data())) {
	+ iqOut=ix;
	+ quark [1] = born->bornOutgoing()[ix];
	+ }
	+ else if(LeptonMatcher::Check(born->bornOutgoing()[ix]->data())) {
	+ lepton[1] = born->bornOutgoing()[ix];
	+ leptons_[1] = lepton[1]->dataPtr();
	+ }
	+ }
	+ assert(quark[1]&&lepton[1]);
	+ // Particle data objects
	+ for(unsigned int ix=0;ix<2;++ix) partons_[ix] = quark[ix]->dataPtr();
	+ // extract the born variables
	+ q_ =lepton[0]->momentum()-lepton[1]->momentum();
	+ q2_ = -q_.m2();
	+ double yB =
	+ ( q_*quark[0]->momentum())/
	+ (lepton[0]->momentum()*quark[0]->momentum());
	+ l_ = 2./yB-1.;
	+ // construct lorentz transform from lab to breit frame
	+ Lorentz5Momentum phadron = hadron->momentum();
	+ phadron.setMass(0.*GeV);
	+ phadron.rescaleRho();
	+ Lorentz5Momentum pb = quark[0]->momentum();
	+ Axis axis(q_.vect().unit());
	+ double sinth(sqrt(sqr(axis.x())+sqr(axis.y())));
	+ LorentzRotation rot_ = LorentzRotation();
	+ if(axis.perp2()>1e-20) {
	+ rot_.setRotate(-acos(axis.z()),Axis(-axis.y()/sinth,axis.x()/sinth,0.));
	+ rot_.rotateX(Constants::pi);
	+ }
	+ if(abs(1.-q_.e()/q_.vect().mag())>1e-6) rot_.boostZ( q_.e()/q_.vect().mag());
	+ pb *= rot_;
	+ if(pb.perp2()/GeV2>1e-20) {
	+ Boost trans = -1./pb.e()*pb.vect();
	+ trans.setZ(0.);
	+ rot_.boost(trans);
	+ }
	+ Lorentz5Momentum pl = rot_*lepton[0]->momentum();
	+ rot_.rotateZ(-atan2(pl.y(),pl.x()));
	+ // momenta of the particles
	+ pl_[0]=rot_*lepton[0]->momentum();
	+ pl_[1]=rot_*lepton[1]->momentum();
	+ pq_[0]=rot_* quark[0]->momentum();
	+ pq_[1]=rot_* quark[1]->momentum();
	+ q_ *= rot_;
	+ // coefficient for the matrix elements
	+ acoeff_ = A(lepton[0]->dataPtr(),lepton[1]->dataPtr(),
	+ quark [0]->dataPtr(),quark [1]->dataPtr(),q2_);
	+ // generate a compton point
	+ generateCompton();
	+ generateBGF();
	+ // no valid emission, return
	+ if(pTCompton_<ZERO&&pTBGF_<ZERO) {
	+ born->pT()[ShowerInteraction::QCD] = pTmin_;
	+ return born;
	+ }
	+ // type of emission, pick highest pT
	+ bool isCompton=pTCompton_>pTBGF_;
	+ // create the process with real emission
	+ bool isQuark = quark[0]->colourLine();
	+ bool FSR = false;
	+ // incoming lepton if first
	+ if(iqIn==1)
	+ born->incoming().push_back(born->bornIncoming()[0]->dataPtr()->
	+ produceParticle(born->bornIncoming()[0]->momentum()));
	+ // outgoing lepton if first
	+ if(iqOut==1)
	+ born->outgoing().push_back(born->bornOutgoing()[0]->dataPtr()->
	+ produceParticle(born->bornOutgoing()[0]->momentum()));
	+ PPtr newout,newin,emitted;
	+ // compton hardest
	+ if(isCompton) {
	+ rot_.invert();
	+ for(unsigned int ix=0;ix<ComptonMomenta_.size();++ix) {
	+ ComptonMomenta_[ix].transform(rot_);
	+ }
	+ newout = partons_[1]->produceParticle(ComptonMomenta_[1]);
	+ emitted = gluon_ ->produceParticle(ComptonMomenta_[2]);
	+ newin = partons_[0]->produceParticle(ComptonMomenta_[0]);
	+ emitted->incomingColour(newin,!isQuark);
	+ emitted->colourConnect(newout,!isQuark);
	+ FSR = !ComptonISFS_;
	+ born->pT()[ShowerInteraction::QCD] = pTCompton_;
	+ }
	+ // BGF hardest
	+ else {
	+ rot_.invert();
	+ for(unsigned int ix=0;ix<BGFMomenta_.size();++ix) {
	+ BGFMomenta_[ix].transform(rot_);
	+ }
	+ newin = gluon_ ->produceParticle(BGFMomenta_[0]);
	+ emitted = quark[0]->dataPtr()->CC()->produceParticle(BGFMomenta_[2]);
	+ newout = quark[1]->dataPtr() ->produceParticle(BGFMomenta_[1]);
	+ emitted->incomingColour(newin, isQuark);
	+ newout ->incomingColour(newin,!isQuark);
	+ FSR = false;
	+ born->pT()[ShowerInteraction::QCD] = pTBGF_;
	+ }
	+ double x = newin->momentum().rho()/hadron->momentum().rho();
	+ if(born->incoming().size()==0)
	+ born->x(make_pair(x,1.));
	+ else
	+ born->x(make_pair(1.,x));
	+ if(FSR) {
	+ born->emitter(born->outgoing().size()+2);
	+ born->spectator(born->incoming().size());
	+ }
	+ else {
	+ born->emitter(born->incoming().size());
	+ born->spectator(born->outgoing().size()+2);
	+ }
	+ born->emitted(4);
	+ // radiating particles
	+ born->incoming().push_back(newin );
	+ born->outgoing().push_back(newout);
	+ // incoming lepton if second
	+ if(iqIn==0)
	+ born->incoming().push_back(born->bornIncoming()[1]->dataPtr()->
	+ produceParticle(born->bornIncoming()[1]->momentum()));
	+ // outgoing lepton if second
	+ if(iqOut==0)
	+ born->outgoing().push_back(born->bornOutgoing()[1]->dataPtr()->
	+ produceParticle(born->bornOutgoing()[1]->momentum()));
	+ // radiated particle
	+ born->outgoing().push_back(emitted);
	+ return born;
	}

	void DISBase::generateCompton() {
	// maximum value of the xT
	double xT = sqrt((1.-xB_)/xB_);
	double xTMin = 2.*pTmin_/sqrt(q2_);
	double zp;
	// prefactor
	double a = alpha_->overestimateValue()*comptonWeight_/Constants::twopi;
	// loop to generate kinematics
	double wgt(0.),xp(0.);
	vector<double> azicoeff;
	do {
	wgt = 0.;
	// intergration variables dxT/xT^3
	xT = 1./sqrt(1.-2.log(UseRandom::rnd())/a*sqr(xT));
	// zp
	zp = UseRandom::rnd();
	xp = 1./(1.+0.25*sqr(xT)/zp/(1.-zp));
	// check allowed
	if(xp<xB_\|\|xp>1.) continue;
	// phase-space piece of the weight
	wgt = 8.(1.-xp)zp/comptonWeight_;
	// PDF piece of the weight
	Energy2 scale = q2_((1.-xp)(1-zp)*zp/xp+1.);
	wgt *= pdf_->xfx(beam_,partons_[0],scale,xB_/xp)/
	pdf_->xfx(beam_,partons_[0],q2_ ,xB_);
	// me piece of the weight
	double x2 = 1.-(1.-zp)/xp;
	azicoeff = ComptonME(xp,x2,xT,false);
	wgt = 4./3.alpha_->ratio(0.25q2_sqr(xT))(azicoeff[0]+0.5azicoeff[2]);
	if(wgt>1.\|\|wgt<0.) {
	ostringstream wstring;
	wstring << "DISBase::generateCompton() "
	<< "Weight greater than one or less than zero"
	<< "wgt = " << wgt << "\n";
	generator()->logWarning( Exception(wstring.str(),
	Exception::warning) );
	}
	}
	while(xT>xTMin&&UseRandom::rnd()>wgt);
	if(xT<=xTMin) {
	pTCompton_=-GeV;
	return;
	}
	// generate phi
	unsigned int itry(0);
	double phimax = std::accumulate(azicoeff.begin(),azicoeff.end(),0.);
	double phiwgt,phi;
	do {
	phi = UseRandom::rnd()*Constants::twopi;
	double cphi(cos(phi));
	phiwgt = azicoeff[0]+azicoeff[1]cphi+azicoeff[2]sqr(cphi);
	++itry;
	}
	while (phimax*UseRandom::rnd() > phiwgt && itry<200);
	if(itry==200) throw Exception() << "Too many tries in DISMECorrection"
	<< "::generateCompton() to"
	<< " generate phi" << Exception::eventerror;
	// momenta for the configuration
	Energy Q(sqrt(q2_));
	double x1 = -1./xp;
	double x2 = 1.-(1.-zp)/xp;
	double x3 = 2.+x1-x2;
	Lorentz5Momentum p1( 0.5QxTcos(phi), 0.5QxTsin(phi),
	-0.5Qx2, 0.5Qsqrt(sqr(xT)+sqr(x2)));
	Lorentz5Momentum p2(-0.5QxTcos(phi), -0.5QxTsin(phi),
	-0.5Qx3, 0.5Qsqrt(sqr(xT)+sqr(x3)));
	Lorentz5Momentum p0(ZERO,ZERO,-0.5Qx1,-0.5Qx1);
	pTCompton_ = 0.5QxT;
	ComptonMomenta_.resize(3);
	ComptonMomenta_[0] = p0;
	ComptonMomenta_[1] = p1;
	ComptonMomenta_[2] = p2;
	ComptonISFS_ = zp>xp;
	// debuggingMatrixElement(false,p0,p1,p2,gluon_,pl_[0],pl_[1],pq_[0],pq_[1],
	// leptons_[0],leptons_[1],
	// partons_[0],partons_[1],
	// q2_,phi,x2,x3,xT,zp,xp,azicoeff,false);
	}

	void DISBase::generateBGF() {
	// maximum value of the xT
	double xT = (1.-xB_)/xB_;
	double xTMin = 2.*max(pTmin_,pTCompton_)/sqrt(q2_);
	double zp;
	// prefactor
	double a = alpha_->overestimateValue()*BGFWeight_/Constants::twopi;
	// loop to generate kinematics
	double wgt(0.),xp(0.);
	vector<double> azicoeff;
	do {
	wgt = 0.;
	// intergration variables dxT/xT^3
	xT = 1./sqrt(1.-2.log(UseRandom::rnd())/a*sqr(xT));
	// zp
	zp = UseRandom::rnd();
	xp = 1./(1.+0.25*sqr(xT)/zp/(1.-zp));
	// check allowed
	if(xp<xB_\|\|xp>1.) continue;
	// phase-space piece of the weight
	wgt = 8.sqr(1.-xp)zp/BGFWeight_;
	// PDF piece of the weight
	Energy2 scale = q2_((1.-xp)(1-zp)*zp/xp+1.);
	wgt *= pdf_->xfx(beam_,gluon_ ,scale,xB_/xp)/
	pdf_->xfx(beam_,partons_[0],q2_ ,xB_);
	// me piece of the weight
	double x1 = -1./xp;
	double x2 = 1.-(1.-zp)/xp;
	double x3 = 2.+x1-x2;
	azicoeff = BGFME(xp,x2,x3,xT,false);
	wgt = 0.5alpha_->ratio(0.25q2_sqr(xT))*
	(azicoeff[0]+0.5*azicoeff[2]);
	if(wgt>1.\|\|wgt<0.) {
	ostringstream wstring;
	wstring << "DISBase::generateBGF() "
	<< "Weight greater than one or less than zero"
	<< "wgt = " << wgt << "\n";
	generator()->logWarning( Exception(wstring.str(),
	Exception::warning) );
	}
	}
	while(xT>xTMin&&UseRandom::rnd()>wgt);
	if(xT<=xTMin) {
	pTBGF_=-GeV;
	return;
	}
	// generate phi
	unsigned int itry(0);
	double phimax = std::accumulate(azicoeff.begin(),azicoeff.end(),0.);
	double phiwgt,phi;
	do {
	phi = UseRandom::rnd()*Constants::twopi;
	double cphi(cos(phi));
	phiwgt = azicoeff[0]+azicoeff[1]cphi+azicoeff[2]sqr(cphi);
	++itry;
	}
	while (phimax*UseRandom::rnd() > phiwgt && itry<200);
	if(itry==200) throw Exception() << "Too many tries in DISMECorrection"
	<< "::generateBGF() to"
	<< " generate phi" << Exception::eventerror;
	// momenta for the configuration
	Energy Q(sqrt(q2_));
	double x1 = -1./xp;
	double x2 = 1.-(1.-zp)/xp;
	double x3 = 2.+x1-x2;
	Lorentz5Momentum p1( 0.5QxTcos(phi), 0.5QxTsin(phi),
	-0.5Qx2, 0.5Qsqrt(sqr(xT)+sqr(x2)));
	Lorentz5Momentum p2(-0.5QxTcos(phi), -0.5QxTsin(phi),
	-0.5Qx3, 0.5Qsqrt(sqr(xT)+sqr(x3)));
	Lorentz5Momentum p0(ZERO,ZERO,-0.5Qx1,-0.5Qx1);
	pTBGF_=0.5QxT;
	BGFMomenta_.resize(3);
	BGFMomenta_[0]=p0;
	BGFMomenta_[1]=p1;
	BGFMomenta_[2]=p2;
	// debuggingMatrixElement(true,p0,p1,p2,gluon_,pl_[0],pl_[1],pq_[0],pq_[1],
	// leptons_[0],leptons_[1],
	// partons_[0],partons_[1],
	// q2_,phi,x2,x3,xT,zp,xp,azicoeff,false);
	}

	int DISBase::nDim() const {
	return HwMEBase::nDim() + (contrib_>0 ? 1 : 0 );
	}

	bool DISBase::generateKinematics(const double * r) {
	// Born kinematics
	if(!HwMEBase::generateKinematics(r)) return false;
	if(contrib_!=0) {
	// hadron and momentum fraction
	if(HadronMatcher::Check(*lastParticles().first->dataPtr())) {
	hadron_ = dynamic_ptr_cast<tcBeamPtr>(lastParticles().first->dataPtr());
	xB_ = lastX1();
	}
	else {
	hadron_ = dynamic_ptr_cast<tcBeamPtr>(lastParticles().second->dataPtr());
	xB_ = lastX2();
	}
	// Q2
	q2_ = -(meMomenta()[0]-meMomenta()[2]).m2();
	// xp
	int ndim=nDim();
	double rhomin = pow(1.-xB_,1.-power_);
	double rho = r[ndim-1]*rhomin;
	xp_ = 1.-pow(rho,1./(1.-power_));
	jac_ = rhomin/(1.-power_)*pow(1.-xp_,power_);
	jacobian(jacobian()*jac_);
	}
	return true;
	}

	Energy2 DISBase::scale() const {
	return scaleOpt_ == 1 ?
	-sqr(scaleFact_)tHat() : sqr(scaleFact_muF_);
	}

	CrossSection DISBase::dSigHatDR() const {
	return NLOWeight()*HwMEBase::dSigHatDR();
	}

	double DISBase::NLOWeight() const {
	// If only leading order is required return 1:
	if(contrib_==0) return 1.;
	// scale and prefactors
	Energy2 mu2(scale());
	double aS = SM().alphaS(mu2);
	double CFfact = 4./3.*aS/Constants::twopi;
	double TRfact = 1./2.*aS/Constants::twopi;
	// LO + dipole subtracted virtual + collinear quark bit with LO pdf
	double virt = 1.+CFfact(-4.5-1./3.sqr(Constants::pi)+1.5*log(q2_/mu2/(1.-xB_))
	+2.log(1.-xB_)log(q2_/mu2)+sqr(log(1.-xB_)));
	virt /= jac_;
	// PDF from leading-order
	double loPDF = hadron_->pdf()->xfx(hadron_,mePartonData()[1],mu2,xB_)/xB_;
	// NLO gluon PDF
	tcPDPtr gluon = getParticleData(ParticleID::g);
	double gPDF = hadron_->pdf()->xfx(hadron_,gluon,mu2,xB_/xp_)*xp_/xB_;
	// NLO quark PDF
	double qPDF = hadron_->pdf()->xfx(hadron_,mePartonData()[1],mu2,xB_/xp_)*xp_/xB_;
	// collinear counterterms
	// gluon
	double collg =
	TRfact/xp_gPDF(2.xp_(1.-xp_)+(sqr(xp_)+sqr(1.-xp_))log((1.-xp_)q2_/xp_/mu2));
	// quark
	double collq =
	CFfact/xp_qPDF(1-xp_-2./(1.-xp_)log(xp_)-(1.+xp_)log((1.-xp_)/xp_*q2_/mu2))+
	CFfact/xp_(qPDF-xp_loPDF)(2./(1.-xp_)log(q2_*(1.-xp_)/mu2)-1.5/(1.-xp_));
	// calculate the A coefficient for the real pieces
	double a(A(mePartonData()[0],mePartonData()[2],
	mePartonData()[1],mePartonData()[3],q2_));
	// cacluate lepton kinematic variables
	Lorentz5Momentum q = meMomenta()[0]-meMomenta()[2];
	double yB = (qmeMomenta()[1])/(meMomenta()[0]meMomenta()[1]);
	double l = 2./yB-1.;
	// q -> qg term
	double realq = CFfact/xp_/(1.+al+sqr(l))qPDF/loPDF*
	(2.+2.sqr(l)-xp_+3.xp_sqr(l)+al(2.xp_+1.));
	// g -> q qbar term
	double realg =-TRfact/xp_/(1.+al+sqr(l))gPDF/loPDF*
	((1.+sqr(l)+2.(1.-3.sqr(l))xp_(1.-xp_))
	+2.al(1.-2.xp_*(1.-xp_)));
	// return the full result
	double wgt = virt+((collq+collg)/loPDF+realq+realg);
	// double f2g = gPDF/xp_TRfact((sqr(1-xp_)+sqr(xp_))*log((1-xp_)/xp_)+
	// 8xp_(1.-xp_)-1.);
	// double f2q =
	// loPDF/jac_(1.+CFfact(-1.5*log(1.-xB_)+sqr(log(1.-xB_))
	// -sqr(Constants::pi)/3.-4.5))
	// +qPDF CFfact/xp_(3.+2.xp_-(1.+xp_)log(1.-xp_)
	// -(1.+sqr(xp_))/(1.-xp_)*log(xp_))
	// +(qPDF-xp_loPDF)CFfact/xp_(2.log(1.-xp_)/(1.-xp_)-1.5/(1.-xp_));
	// double wgt = (f2g+f2q)/loPDF;
	return contrib_ == 1 ? max(0.,wgt) : max(0.,-wgt);
	}

File Metadata

Mime Type: text/x-diff
Expires: Tue, Nov 19, 8:41 PM (1 d, 3 h)
Storage Engine: blob
Storage Format: Raw Data
Storage Handle: 3797247
Default Alt Text: (56 KB)

No OneTemporaryActions

View Options

File Metadata

Event Timeline

No OneTemporary
Actions