diff --git a/Hadronization/ClusterFissioner.cc b/Hadronization/ClusterFissioner.cc
--- a/Hadronization/ClusterFissioner.cc
+++ b/Hadronization/ClusterFissioner.cc
@@ -1,1506 +1,1768 @@
 // -*- C++ -*-
 //
 // ClusterFissioner.cc is a part of Herwig - A multi-purpose Monte Carlo event generator
 // Copyright (C) 2002-2019 The Herwig Collaboration
 //
 // Herwig is licenced under version 3 of the GPL, see COPYING for details.
 // Please respect the MCnet academic guidelines, see GUIDELINES for details.
 //
 //
 // Thisk is the implementation of the non-inlined, non-templated member
 // functions of the ClusterFissioner class.
 //
 
 #include "ClusterFissioner.h"
 #include <ThePEG/Interface/ClassDocumentation.h>
 #include <ThePEG/Interface/Reference.h>
 #include <ThePEG/Interface/Parameter.h>
 #include <ThePEG/Interface/Switch.h>
 #include <ThePEG/Persistency/PersistentOStream.h>
 #include <ThePEG/Persistency/PersistentIStream.h>
 #include <ThePEG/PDT/EnumParticles.h>
 #include "Herwig/Utilities/Kinematics.h"
 #include "Cluster.h"
 #include "ThePEG/Repository/UseRandom.h"
 #include "ThePEG/Repository/EventGenerator.h"
 #include <ThePEG/Utilities/DescribeClass.h>
 #include "ThePEG/Interface/ParMap.h"
 
+#include <boost/numeric/ublas/matrix.hpp>
+#include <boost/numeric/ublas/io.hpp>
 using namespace Herwig;
 
 DescribeClass<ClusterFissioner,Interfaced>
 describeClusterFissioner("Herwig::ClusterFissioner","Herwig.so");
 
 ClusterFissioner::ClusterFissioner() :
   _clMaxLight(3.35*GeV),
   _clMaxExotic(3.35*GeV),
   _clPowLight(2.0),
   _clPowExotic(2.0),
   _pSplitLight(1.0),
   _pSplitExotic(1.0),
   _phaseSpaceWeights(false),
   _dim(4),
   _fissionCluster(0),
   _kinematicThresholdChoice(0),
   _pwtDIquark(0.0),
   _diquarkClusterFission(0),
   _btClM(1.0*GeV),
   _iopRem(1),
   _kappa(1.0e15*GeV/meter),
   _kinematics(0),
   _fluxTubeWidth(1.0*GeV),
   _enhanceSProb(0),
   _m0Fission(2.*GeV),
   _massMeasure(0),
   _probPowFactor(4.0),
   _probShift(0.0),
   _kinThresholdShift(1.0*sqr(GeV)),
   _strictDiquarkKinematics(0)
 {}
 
 IBPtr ClusterFissioner::clone() const {
   return new_ptr(*this);
 }
 
 IBPtr ClusterFissioner::fullclone() const {
   return new_ptr(*this);
 }
 
 void ClusterFissioner::persistentOutput(PersistentOStream & os) const {
   os << ounit(_clMaxLight,GeV)
      << ounit(_clMaxHeavy,GeV) << ounit(_clMaxExotic,GeV) << _clPowLight << _clPowHeavy
      << _clPowExotic << _pSplitLight
      << _pSplitHeavy << _pSplitExotic
      << _fissionCluster << _fissionPwt
 	 << _pwtDIquark
 	 << _diquarkClusterFission
 	 << _kinematics
 	 << ounit(_fluxTubeWidth,GeV)
 	 << ounit(_btClM,GeV)
      << _iopRem  << ounit(_kappa, GeV/meter)
      << _enhanceSProb << ounit(_m0Fission,GeV) << _massMeasure << _dim << _phaseSpaceWeights
      << _hadronSpectrum
      << _probPowFactor << _probShift << ounit(_kinThresholdShift,sqr(GeV))
 	 << _strictDiquarkKinematics;
 }
 
 void ClusterFissioner::persistentInput(PersistentIStream & is, int) {
   is >> iunit(_clMaxLight,GeV)
      >> iunit(_clMaxHeavy,GeV) >> iunit(_clMaxExotic,GeV) >> _clPowLight >> _clPowHeavy
      >> _clPowExotic >> _pSplitLight
      >> _pSplitHeavy >> _pSplitExotic
      >> _fissionCluster >> _fissionPwt
 	 >> _pwtDIquark
 	 >> _diquarkClusterFission
 	 >> _kinematics
 	 >> iunit(_fluxTubeWidth,GeV)
      >> iunit(_btClM,GeV)
 	 >> _iopRem >> iunit(_kappa, GeV/meter)
      >> _enhanceSProb >> iunit(_m0Fission,GeV) >> _massMeasure >> _dim >> _phaseSpaceWeights
 
      >> _hadronSpectrum
      >> _probPowFactor >> _probShift >> iunit(_kinThresholdShift,sqr(GeV))
 	 >> _strictDiquarkKinematics;
 }
 
 void ClusterFissioner::doinit() {
   Interfaced::doinit();
   for ( const long& id : spectrum()->heavyHadronizingQuarks() ) {
     if ( _pSplitHeavy.find(id) == _pSplitHeavy.end() ||
 	 _clPowHeavy.find(id) == _clPowHeavy.end() ||
 	 _clMaxHeavy.find(id) == _clMaxHeavy.end() )
       throw InitException() << "not all parameters have been set for heavy quark cluster fission";
   }
   // for default Pwts not needed to initialize
   if (_fissionCluster==0) return;  
   for ( const long& id : spectrum()->lightHadronizingQuarks() ) {
 	  if ( _fissionPwt.find(id) == _fissionPwt.end() )
 		  // check that all relevant weights are set
 		  throw InitException() << "fission weights for light quarks have not been set";
   }
   /*
   // Not needed since we set Diquark weights from quark weights
   for ( const long& id : spectrum()->lightHadronizingDiquarks() ) {
 	  if ( _fissionPwt.find(id) == _fissionPwt.end() )
 		  throw InitException() << "fission weights for light diquarks have not been set";
   }*/
   double pwtDquark=_fissionPwt.find(ParticleID::d)->second;
   double pwtUquark=_fissionPwt.find(ParticleID::u)->second;
   double pwtSquark=_fissionPwt.find(ParticleID::s)->second;
   // ERROR: TODO makeDiquarkID is protected function ?
   // _fissionPwt[spectrum()->makeDiquarkID(ParticleID::d,ParticleID::d,3)] =       _pwtDIquark * pwtDquark * pwtDquark;
   // _fissionPwt[spectrum()->makeDiquarkID(ParticleID::u,ParticleID::d,1)] = 0.5 * _pwtDIquark * pwtUquark * pwtDquark;
   // _fissionPwt[spectrum()->makeDiquarkID(ParticleID::u,ParticleID::u,3)] =       _pwtDIquark * pwtUquark * pwtUquark;
   // _fissionPwt[spectrum()->makeDiquarkID(ParticleID::s,ParticleID::d,1)] = 0.5 * _pwtDIquark * pwtSquark * pwtDquark;
   // _fissionPwt[spectrum()->makeDiquarkID(ParticleID::s,ParticleID::u,1)] = 0.5 * _pwtDIquark * pwtSquark * pwtUquark;
   // _fissionPwt[spectrum()->makeDiquarkID(ParticleID::s,ParticleID::s,3)] =       _pwtDIquark * pwtSquark * pwtSquark;
   // TODO magic  number alternative
   _fissionPwt[1103] =       _pwtDIquark * pwtDquark * pwtDquark;
   _fissionPwt[2101] = 0.5 * _pwtDIquark * pwtUquark * pwtDquark;
   _fissionPwt[2203] =       _pwtDIquark * pwtUquark * pwtUquark;
   _fissionPwt[3101] = 0.5 * _pwtDIquark * pwtSquark * pwtDquark;
   _fissionPwt[3201] = 0.5 * _pwtDIquark * pwtSquark * pwtUquark;
   _fissionPwt[3303] =       _pwtDIquark * pwtSquark * pwtSquark;
 }
 
 void ClusterFissioner::Init() {
 
   static ClassDocumentation<ClusterFissioner> documentation
     ("Class responsibles for chopping up the clusters");
 
   static Reference<ClusterFissioner,HadronSpectrum> interfaceHadronSpectrum
     ("HadronSpectrum",
      "Set the Hadron spectrum for this cluster fissioner.",
      &ClusterFissioner::_hadronSpectrum, false, false, true, false);
 
   // ClMax for light, Bottom, Charm and exotic (e.g. Susy) quarks
   static Parameter<ClusterFissioner,Energy>
     interfaceClMaxLight ("ClMaxLight","cluster max mass for light quarks (unit [GeV])",
                     &ClusterFissioner::_clMaxLight, GeV, 3.35*GeV, ZERO, 10.0*GeV,
 		    false,false,false);  
   static ParMap<ClusterFissioner,Energy> interfaceClMaxHeavy
     ("ClMaxHeavy",
      "ClMax for heavy quarkls",
      &ClusterFissioner::_clMaxHeavy, GeV, -1, 3.35*GeV, ZERO, 10.0*GeV,
      false, false, Interface::upperlim);
   static Parameter<ClusterFissioner,Energy>
     interfaceClMaxExotic ("ClMaxExotic","cluster max mass  for exotic quarks (unit [GeV])",
                     &ClusterFissioner::_clMaxExotic, GeV, 3.35*GeV, ZERO, 10.0*GeV,
 		    false,false,false);
 
  // ClPow for light, Bottom, Charm and exotic (e.g. Susy) quarks
  static Parameter<ClusterFissioner,double>
     interfaceClPowLight ("ClPowLight","cluster mass exponent for light quarks",
                     &ClusterFissioner::_clPowLight, 0, 2.0, 0.0, 10.0,false,false,false); 
   static ParMap<ClusterFissioner,double> interfaceClPowHeavy
     ("ClPowHeavy",
      "ClPow for heavy quarks",
      &ClusterFissioner::_clPowHeavy, -1, 1.0, 0.0, 10.0,
      false, false, Interface::upperlim); 
  static Parameter<ClusterFissioner,double>
     interfaceClPowExotic ("ClPowExotic","cluster mass exponent for exotic quarks",
                     &ClusterFissioner::_clPowExotic, 0, 2.0, 0.0, 10.0,false,false,false);
 
  // PSplit for light, Bottom, Charm and exotic (e.g. Susy) quarks
   static Parameter<ClusterFissioner,double>
     interfacePSplitLight ("PSplitLight","cluster mass splitting param for light quarks",
                     &ClusterFissioner::_pSplitLight, 0, 1.0, 0.0, 10.0,false,false,false);
   static ParMap<ClusterFissioner,double> interfacePSplitHeavy
     ("PSplitHeavy",
      "PSplit for heavy quarks",
      &ClusterFissioner::_pSplitHeavy, -1, 1.0, 0.0, 10.0,
      false, false, Interface::upperlim);
  static Parameter<ClusterFissioner,double>
     interfacePSplitExotic ("PSplitExotic","cluster mass splitting param for exotic quarks",
                     &ClusterFissioner::_pSplitExotic, 0, 1.0, 0.0, 10.0,false,false,false);
 
 
   static Switch<ClusterFissioner,int> interfaceFission
     ("Fission",
      "Option for different Fission options",
      &ClusterFissioner::_fissionCluster, 1, false, false);
   static SwitchOption interfaceFissionDefault
     (interfaceFission,
      "default",
      "Normal cluster fission which depends on the hadron selector class.",
      0);
   static SwitchOption interfaceFissionNew
     (interfaceFission,
      "new",
      "Alternative cluster fission which does not depend on the hadron selector class",
      1);
 
   
 
   static Switch<ClusterFissioner,int> interfaceDiquarkClusterFission
     ("DiquarkClusterFission",
      "Allow clusters to fission to 1 or 2 diquark Clusters",
      &ClusterFissioner::_diquarkClusterFission, 0, false, false);
   static SwitchOption interfaceDiquarkClusterFissionAll
 	(interfaceDiquarkClusterFission,
      "All",
      "Allow diquark clusters and baryon clusters to fission to new diquark Clusters",
      2);
   static SwitchOption interfaceDiquarkClusterFissionOnlyBaryonClusters
 	(interfaceDiquarkClusterFission,
      "OnlyBaryonClusters",
      "Allow only baryon clusters to fission to new diquark Clusters",
      1);
   static SwitchOption interfaceDiquarkClusterFissionNo
     (interfaceDiquarkClusterFission,
      "No",
      "Don't allow clusters to fission to new diquark Clusters",
      0);
 
   static ParMap<ClusterFissioner,double> interfaceFissionPwt
     ("FissionPwt",
      "The weights for quarks in the fission process.",
      &ClusterFissioner::_fissionPwt, -1, 1.0, 0.0, 10.0,
      false, false, Interface::upperlim);
 
   
 
   static Switch<ClusterFissioner,int> interfaceRemnantOption
     ("RemnantOption",
      "Option for the treatment of remnant clusters",
      &ClusterFissioner::_iopRem, 1, false, false);
   static SwitchOption interfaceRemnantOptionSoft
     (interfaceRemnantOption,
      "Soft",
      "Both clusters produced in the fission of the beam cluster"
      " are treated as soft clusters.",
      0);
   static SwitchOption interfaceRemnantOptionHard
     (interfaceRemnantOption,
      "Hard",
      "Only the cluster containing the remnant is treated as a soft cluster.",
      1);
   static SwitchOption interfaceRemnantOptionVeryHard
     (interfaceRemnantOption,
      "VeryHard",
      "Even remnant clusters are treated as hard, i.e. all clusters the same",
      2);
 
   static Parameter<ClusterFissioner,Energy> interfaceBTCLM
     ("SoftClusterFactor",
      "Parameter for the mass spectrum of remnant clusters",
      &ClusterFissioner::_btClM, GeV, 1.*GeV, 0.1*GeV, 10.0*GeV,
      false, false, Interface::limited);
 
 
   static Parameter<ClusterFissioner,Tension> interfaceStringTension
     ("StringTension",
      "String tension used in vertex displacement calculation",
      &ClusterFissioner::_kappa, GeV/meter,
      1.0e15*GeV/meter, ZERO, ZERO,
      false, false, Interface::lowerlim);
 
   static Switch<ClusterFissioner,int> interfaceEnhanceSProb
     ("EnhanceSProb",
      "Option for enhancing strangeness",
      &ClusterFissioner::_enhanceSProb, 0, false, false);
   static SwitchOption interfaceEnhanceSProbNo
     (interfaceEnhanceSProb,
      "No",
      "No strangeness enhancement.",
      0);
   static SwitchOption interfaceEnhanceSProbScaled
     (interfaceEnhanceSProb,
      "Scaled",
      "Scaled strangeness enhancement",
      1);
   static SwitchOption interfaceEnhanceSProbExponential
     (interfaceEnhanceSProb,
      "Exponential",
      "Exponential strangeness enhancement",
      2);
   static Switch<ClusterFissioner,int> interfaceKinematics
     ("Kinematics",
      "Option for selecting different Kinematics for ClusterFission",
      &ClusterFissioner::_kinematics, 0, false, false);
   static SwitchOption interfaceKinematicsDefault
     (interfaceKinematics,
      "Default",
      "Fully aligned Cluster Fission along the Original cluster direction",
      0);
   static SwitchOption interfaceKinematicsIsotropic
     (interfaceKinematics,
      "Isotropic",
      "Fully isotropic two body decay. Not recommended!",
      1);
   static SwitchOption interfaceKinematicsFluxTube
     (interfaceKinematics,
      "FluxTube",
      "Aligned decay with gaussian pT kick with sigma=ClusterFissioner::FluxTube",
      2);
 
    static Switch<ClusterFissioner,int> interfaceMassMeasure
      ("MassMeasure",
       "Option to use different mass measures",
       &ClusterFissioner::_massMeasure,0,false,false);
    static SwitchOption interfaceMassMeasureMass
      (interfaceMassMeasure,
       "Mass",
       "Mass Measure",
       0);
    static SwitchOption interfaceMassMeasureLambda
      (interfaceMassMeasure,
       "Lambda",
       "Lambda Measure",
       1);
 
   static Parameter<ClusterFissioner,Energy> interfaceFissionMassScale
     ("FissionMassScale",
      "Cluster fission mass scale",
      &ClusterFissioner::_m0Fission, GeV, 2.0*GeV, 0.1*GeV, 50.*GeV,
      false, false, Interface::limited);
 
   static Parameter<ClusterFissioner,double> interfaceProbPowFactor
      ("ProbablityPowerFactor",
       "Power factor in ClausterFissioner bell probablity function",
       &ClusterFissioner::_probPowFactor, 2.0, 1.0, 20.0,
       false, false, Interface::limited);
 
   static Parameter<ClusterFissioner,Energy> interfaceFluxTubeWidth
     ("FluxTubeWidth",
      "sigma of gaussian sampling of pT for FluxTube kinematics",
      &ClusterFissioner::_fluxTubeWidth, GeV, 2.0*GeV, 1.0e-30*GeV, 5.0*GeV,
      false, false, Interface::limited);
 
   static Parameter<ClusterFissioner,double> interfaceProbShift
      ("ProbablityShift",
       "Shifts from the center in ClausterFissioner bell probablity function",
       &ClusterFissioner::_probShift, 0.0, -10.0, 10.0,
       false, false, Interface::limited);
 
   static Parameter<ClusterFissioner,Energy2> interfaceKineticThresholdShift
      ("KineticThresholdShift",
       "Shifts from the kinetic threshold in ClausterFissioner",
       &ClusterFissioner::_kinThresholdShift, sqr(GeV), 0.*sqr(GeV), -10.0*sqr(GeV), 10.0*sqr(GeV),
       false, false, Interface::limited);
 
   static Switch<ClusterFissioner,int> interfaceKinematicThreshold
     ("KinematicThreshold",
      "Option for using static or dynamic kinematic thresholds in cluster splittings",
      &ClusterFissioner::_kinematicThresholdChoice, 0, false, false);
   static SwitchOption interfaceKinematicThresholdStatic
     (interfaceKinematicThreshold,
      "Static",
      "Set static kinematic thresholds for cluster splittings.",
      0);
   static SwitchOption interfaceKinematicThresholdDynamic
     (interfaceKinematicThreshold,
      "Dynamic",
      "Set dynamic kinematic thresholds for cluster splittings.",
      1);
 
   
   static Switch<ClusterFissioner,bool> interfacePhaseSpaceWeights
     ("PhaseSpaceWeights",
      "Include phase space weights.",
      &ClusterFissioner::_phaseSpaceWeights, false, false, false);
   static SwitchOption interfacePhaseSpaceWeightsYes
     (interfacePhaseSpaceWeights,
      "Yes",
      "Do include the effect of cluster fission phase space",
      true);
   static SwitchOption interfacePhaseSpaceWeightsNo
     (interfacePhaseSpaceWeights,
      "No",
      "Do not include the effect of cluster phase space",
      false);
 
   static Parameter<ClusterFissioner,double>
     interfaceDim ("Dimension","Dimension in which phase space weights are calculated",
 	 &ClusterFissioner::_dim, 0, 4.0, 3.0, 10.0,false,false, Interface::limited);
 
   static Switch<ClusterFissioner,int> interfaceStrictDiquarkKinematics
     ("StrictDiquarkKinematics",
      "Option for selecting different selection criterions of diquarks for ClusterFission",
      &ClusterFissioner::_strictDiquarkKinematics, 0, false, false);
   static SwitchOption interfaceStrictDiquarkKinematicsLoose
     (interfaceStrictDiquarkKinematics,
      "Loose",
      "No kinematic threshold for diquark selection except for Mass bigger than 2 baryons",
      0);
   static SwitchOption interfaceStrictDiquarkKinematicsStrict
     (interfaceStrictDiquarkKinematics,
      "Strict",
      "Resulting clusters are at least as heavy as 2 lightest baryons",
      1);
 
   static Parameter<ClusterFissioner,double> interfacePwtDIquark
      ("PwtDIquark",
       "specific probability for choosing a d diquark",
       &ClusterFissioner::_pwtDIquark, 0.0, 0.0, 10.0,
       false, false, Interface::limited);
 }
 
 tPVector ClusterFissioner::fission(ClusterVector & clusters, bool softUEisOn) {
   // return if no clusters
   if (clusters.empty()) return tPVector();
 
   /*****************
    * Loop over the (input) collection of cluster pointers, and store in
    * the vector  splitClusters  all the clusters that need to be split
    * (these are beam clusters, if soft underlying event is off, and
    *  heavy non-beam clusters).
    ********************/
 
   stack<ClusterPtr> splitClusters;
   for(ClusterVector::iterator it = clusters.begin() ;
       it != clusters.end() ; ++it) {
     /**************
      * Skip 3-component clusters that have been redefined (as 2-component
      * clusters) or not available clusters. The latter check is indeed
      * redundant now, but it is used for possible future extensions in which,
      * for some reasons, some of the clusters found by ClusterFinder are tagged
      * straight away as not available.
      **************/
     if((*it)->isRedefined() || !(*it)->isAvailable()) continue;
     // if the cluster is a beam cluster add it to the vector of clusters
     // to be split or if it is heavy
     if((*it)->isBeamCluster() || isHeavy(*it)) splitClusters.push(*it);
   }
   tPVector finalhadrons;
   cut(splitClusters, clusters, finalhadrons, softUEisOn);
   return finalhadrons;
 }
 
 void ClusterFissioner::cut(stack<ClusterPtr> & clusterStack,
    			   ClusterVector &clusters, tPVector & finalhadrons,
 			   bool softUEisOn) {
   /**************************************************
    * This method does the splitting of the cluster pointed by  cluPtr
    * and "recursively" by all of its cluster children, if heavy. All of these
    * new children clusters are added (indeed the pointers to them) to the
    * collection of cluster pointers  collecCluPtr. The method works as follows.
    * Initially the vector vecCluPtr contains just the input pointer to the
    * cluster to be split. Then it will be filled "recursively" by all
    * of the cluster's children that are heavy enough to require, in their turn,
    * to be split. In each loop, the last element of the vector vecCluPtr is
    * considered (only once because it is then removed from the vector).
    * This approach is conceptually recursive, but avoid the overhead of
    * a concrete recursive function. Furthermore it requires minimal changes
    * in the case that the fission of an heavy cluster could produce more
    * than two cluster children as assumed now.
    *
    * Draw the masses: for normal, non-beam clusters a power-like mass dist
    * is used, whereas for beam clusters a fast-decreasing exponential mass
    * dist is used instead (to avoid many iterative splitting which could
    * produce an unphysical large transverse energy from a supposed soft beam
    * remnant process).
    ****************************************/
   // Here we recursively loop over clusters in the stack and cut them
   while (!clusterStack.empty()) {
     // take the last element of the vector
     ClusterPtr iCluster = clusterStack.top(); clusterStack.pop();
     // split it
     cutType ct = iCluster->numComponents() == 2 ?
       cutTwo(iCluster, finalhadrons, softUEisOn) :
       cutThree(iCluster, finalhadrons, softUEisOn);
 
     // There are cases when we don't want to split, even if it fails mass test
     if(!ct.first.first || !ct.second.first) {
       // if an unsplit beam cluster leave if for the underlying event
       if(iCluster->isBeamCluster() && softUEisOn)
 	iCluster->isAvailable(false);
       continue;
     }
     // check if clusters
     ClusterPtr one = dynamic_ptr_cast<ClusterPtr>(ct.first.first);
     ClusterPtr two = dynamic_ptr_cast<ClusterPtr>(ct.second.first);
     // is a beam cluster must be split into two clusters
     if(iCluster->isBeamCluster() && (!one||!two) && softUEisOn) {
       iCluster->isAvailable(false);
       continue;
     }
 
     // There should always be a intermediate quark(s) from the splitting
     assert(ct.first.second && ct.second.second);
     /// \todo sort out motherless quark pairs here. Watch out for 'quark in final state' errors
     iCluster->addChild(ct.first.first);
     //    iCluster->addChild(ct.first.second);
     //    ct.first.second->addChild(ct.first.first);
 
     iCluster->addChild(ct.second.first);
     //    iCluster->addChild(ct.second.second);
     //    ct.second.second->addChild(ct.second.first);
 
     // Sometimes the clusters decay C -> H + C' or C -> H + H' rather then C -> C' + C''
     if(one) {
       clusters.push_back(one);
       if(one->isBeamCluster() && softUEisOn)
 	one->isAvailable(false);
       if(isHeavy(one) && one->isAvailable())
 	clusterStack.push(one);
     }
     if(two) {
       clusters.push_back(two);
       if(two->isBeamCluster() && softUEisOn)
 	two->isAvailable(false);
       if(isHeavy(two) && two->isAvailable())
 	clusterStack.push(two);
     }
   }
 }
 
 ClusterFissioner::cutType
 ClusterFissioner::cutTwo(ClusterPtr & cluster, tPVector & finalhadrons,
 			 bool softUEisOn) {
   // need to make sure only 2-cpt clusters get here
   assert(cluster->numComponents() == 2);
   tPPtr ptrQ1 = cluster->particle(0);
   tPPtr ptrQ2 = cluster->particle(1);
   Energy Mc = cluster->mass();
   assert(ptrQ1);
   assert(ptrQ2);
 
   // And check if those particles are from a beam remnant
   bool rem1 = cluster->isBeamRemnant(0);
   bool rem2 = cluster->isBeamRemnant(1);
   // workout which distribution to use
   bool soft1(false),soft2(false);
   switch (_iopRem) {
   case 0:
     soft1 = rem1 || rem2;
     soft2 = rem2 || rem1;
     break;
   case 1:
     soft1 = rem1;
     soft2 = rem2;
     break;
   }
   // Initialization for the exponential ("soft") mass distribution.
   static const int max_loop = 1000;
   int counter = 0;
   Energy Mc1 = ZERO, Mc2 = ZERO,m1=ZERO,m2=ZERO,m=ZERO;
   tcPDPtr toHadron1, toHadron2;
   PPtr newPtr1 = PPtr ();
   PPtr newPtr2 = PPtr ();
   bool succeeded = false;
   Lorentz5Momentum pClu1, pClu2, pQ1, pQone, pQtwo, pQ2;
   do
     {
       succeeded = false;
       ++counter;
       // get a flavour for the qqbar pair
       drawNewFlavour(newPtr1,newPtr2,cluster);
       // check for right ordering
       assert (ptrQ2);
       assert (newPtr2);
       assert (ptrQ2->dataPtr());
       assert (newPtr2->dataPtr());
 	  // TODO careful if DiquarkClusters can exist
 	  bool Q1diq = DiquarkMatcher::Check(ptrQ1->id());
 	  bool Q2diq = DiquarkMatcher::Check(ptrQ2->id());
 	  bool newQ1diq = DiquarkMatcher::Check(newPtr1->id());
 	  bool newQ2diq = DiquarkMatcher::Check(newPtr2->id());
 	  bool diqClu1 = Q1diq && newQ1diq;
 	  bool diqClu2 = Q2diq && newQ2diq;
 	  // std::cout << "Make Clusters: ( " << ptrQ1->PDGName() << " " << newPtr1->PDGName() << " ), ( "
 					// << ptrQ2->PDGName() << " " << newPtr2->PDGName() << " )\n";
 	  if (!( diqClu1 || diqClu2 )
 		  && (cantMakeHadron(ptrQ1, newPtr1) || cantMakeHadron(ptrQ2, newPtr2))) {
 		  swap(newPtr1, newPtr2);
 		  // check again
 		  if(cantMakeHadron(ptrQ1, newPtr1) || cantMakeHadron(ptrQ2, newPtr2)) {
 			  throw Exception()
 				  << "ClusterFissioner cannot split the cluster ("
 				  << ptrQ1->PDGName() << ' ' << ptrQ2->PDGName()
 				  << ") into hadrons.\n"
 				  << "drawn Flavour: "<< newPtr1->PDGName()<<"\n"<< Exception::runerror;
 		  }
       }
 	  else if ( diqClu1 || diqClu2 ){
 		  bool swapped=false;
 		  if ( !diqClu1 && cantMakeHadron(ptrQ1,newPtr1) ) {
 			  swap(newPtr1, newPtr2);
 			  swapped=true;
 		  }
 		  if ( !diqClu2 && cantMakeHadron(ptrQ2,newPtr2) ) {
 			  assert(!swapped);
 			  swap(newPtr1, newPtr2);
 		  }
 		  if ( diqClu2 && diqClu1 && ptrQ1->id()*newPtr1->id()>0 ) {
 			  assert(!swapped);
 			  swap(newPtr1, newPtr2);
 		  }
 		  // std::cout << "Make Clusters: ( " << ptrQ1->PDGName() << " " << newPtr1->PDGName() << " ), ( "
 					// << ptrQ2->PDGName() << " " << newPtr2->PDGName() << " )\n";
 		  if (!diqClu1) assert(!cantMakeHadron(ptrQ1,newPtr1));
 		  if (!diqClu2) assert(!cantMakeHadron(ptrQ2,newPtr2));
 	  }
       // Check that new clusters can produce particles and there is enough
       // phase space to choose the drawn flavour
       m1 = ptrQ1->data().constituentMass();
       m2 = ptrQ2->data().constituentMass();
       m  = newPtr1->data().constituentMass();
       // Do not split in the case there is no phase space available
       if(Mc <  m1+m + m2+m) continue;
 
       pQ1.setMass(m1);
       pQone.setMass(m);
       pQtwo.setMass(m);
       pQ2.setMass(m2);
 
       pair<Energy,Energy> res = drawNewMasses(Mc, soft1, soft2, pClu1, pClu2,
 					      ptrQ1, pQ1, newPtr1, pQone,
 					      newPtr2, pQtwo, ptrQ2, pQ2);
 
       // derive the masses of the children
       Mc1 = res.first;
       Mc2 = res.second;
       // static kinematic threshold
       if(_kinematicThresholdChoice == 0) {
         if(Mc1 < m1+m || Mc2 < m+m2 || Mc1+Mc2 > Mc) continue;
       // dynamic kinematic threshold
       } else if(_kinematicThresholdChoice == 1) {
         bool C1 = ( sqr(Mc1) )/( sqr(m1) + sqr(m) + _kinThresholdShift ) < 1.0 ? true : false;
         bool C2 = ( sqr(Mc2) )/( sqr(m2) + sqr(m) + _kinThresholdShift ) < 1.0 ? true : false;
         bool C3 = ( sqr(Mc1) + sqr(Mc2) )/( sqr(Mc) ) > 1.0 ? true : false;
 
         if( C1 || C2 || C3 ) continue;
       }
 
       if ( _phaseSpaceWeights ) {
 		  if ( phaseSpaceVeto(Mc,Mc1,Mc2,m,m1,m2) )
 			  continue;
       }
 
 	  if ( Mc1 < spectrum()->massLightestHadronPair(ptrQ1->dataPtr(),newPtr1->dataPtr())) {
 		  // std::cout << "Cluster decays to hadron MC"<< Mc1/GeV << "\t MLHP "<<  spectrum()->massLightestHadronPair(ptrQ1->dataPtr(),newPtr1->dataPtr())/GeV<<"\n";
 		  // std::cout << "Flavour " << ptrQ1->PDGName() <<", " <<  newPtr1->PDGName()<< "\n";
 		  continue;
 	  }
 	  if ( Mc2 < spectrum()->massLightestHadronPair(ptrQ2->dataPtr(),newPtr2->dataPtr())) {
 		  // std::cout << "Cluster decays to hadron MC"<< Mc2/GeV << "\t MLHP "<<  spectrum()->massLightestHadronPair(ptrQ2->dataPtr(),newPtr2->dataPtr())/GeV<<"\n";
 		  // std::cout << "Flavour " << ptrQ2->PDGName() <<", " <<  newPtr2->PDGName()<< "\n";
 		  continue;
 	  }
 
 	  // if (diqClu1) {
 		  // if (Mc1 < spectrum()->massLightestBaryonPair(ptrQ1->dataPtr(),newPtr1->dataPtr())) {
 			  // continue;
 		  // }
 	  // }
 	  // if (diqClu2) {
 		  // if (Mc2 < spectrum()->massLightestBaryonPair(ptrQ2->dataPtr(),newPtr2->dataPtr())) {
 			  // continue;
 		  // }
 	  // }
 
       /**************************
        * New (not present in Fortran Herwig):
        * check whether the fragment masses  Mc1  and  Mc2  are above the
        * threshold for the production of the lightest pair of hadrons with the
        * right flavours. If not, then set by hand the mass to the lightest
        * single hadron with the right flavours, in order to solve correctly
        * the kinematics, and (later in this method) create directly such hadron
        * and add it to the children hadrons of the cluster that undergoes the
        * fission (i.e. the one pointed by iCluPtr). Notice that in this special
        * case, the heavy cluster that undergoes the fission has one single
        * cluster child and one single hadron child. We prefer this approach,
        * rather than to create a light cluster, with the mass set equal to
        * the lightest hadron, and let then the class LightClusterDecayer to do
        * the job to decay it to that single hadron, for two reasons:
        * First, because the sum of the masses of the two constituents can be,
        * in this case, greater than the mass of that hadron, hence it would
        * be impossible to solve the kinematics for such two components, and
        * therefore we would have a cluster whose components are undefined.
        * Second, the algorithm is faster, because it avoids the reshuffling
        * procedure that would be necessary if we used LightClusterDecayer
        * to decay the light cluster to the lightest hadron.
        ****************************/
       // override chosen masses if needed
       toHadron1 = _hadronSpectrum->chooseSingleHadron(ptrQ1->dataPtr(), newPtr1->dataPtr(),Mc1);
       if(toHadron1) { Mc1 = toHadron1->mass(); pClu1.setMass(Mc1); }
       toHadron2 = _hadronSpectrum->chooseSingleHadron(ptrQ2->dataPtr(), newPtr2->dataPtr(),Mc2);
       if(toHadron2) { Mc2 = toHadron2->mass(); pClu2.setMass(Mc2); }
 	  if (toHadron1 || toHadron2) throw Exception()
 		  << "Cluster wants to go to H,C or H,H'" << Exception::runerror;
       // if a beam cluster not allowed to decay to hadrons
       if(cluster->isBeamCluster() && (toHadron1||toHadron2) && softUEisOn)
 	continue;
       // Check if the decay kinematics is still possible: if not then
       // force the one-hadron decay for the other cluster as well.
       if(Mc1 + Mc2  >  Mc) {
 	if(!toHadron1) {
 	  toHadron1 = _hadronSpectrum->chooseSingleHadron(ptrQ1->dataPtr(), newPtr1->dataPtr(),Mc-Mc2);
 	  if(toHadron1) { Mc1 = toHadron1->mass(); pClu1.setMass(Mc1); }
 	}
 	else if(!toHadron2) {
 	  toHadron2 = _hadronSpectrum->chooseSingleHadron(ptrQ2->dataPtr(), newPtr2->dataPtr(),Mc-Mc1);
 	  if(toHadron2) { Mc2 = toHadron2->mass(); pClu2.setMass(Mc2); }
 	}
       }
       succeeded = (Mc >= Mc1+Mc2);
     }
   while (!succeeded && counter < max_loop);
 
   if(counter >= max_loop) {
     static const PPtr null = PPtr();
     return cutType(PPair(null,null),PPair(null,null));
   }
 
   // Determined the (5-components) momenta (all in the LAB frame)
   Lorentz5Momentum pClu = cluster->momentum(); // known
   Lorentz5Momentum p0Q1 = ptrQ1->momentum(); // known (mom Q1 before fission)
   calculateKinematics(pClu,p0Q1,toHadron1,toHadron2,
 		      pClu1,pClu2,pQ1,pQone,pQtwo,pQ2);
 
   /******************
    * The previous methods have determined the kinematics and positions
    * of C -> C1 + C2.
    * In the case that one of the two product is light, that means either
    * decayOneHadronClu1 or decayOneHadronClu2 is true, then the momenta
    * of the components of that light product have not been determined,
    * and a (light) cluster will not be created: the heavy father cluster
    * decays, in this case, into a single (not-light) cluster and a
    * single hadron. In the other, "normal", cases the father cluster
    * decays into two clusters, each of which has well defined components.
    * Notice that, in the case of components which point to particles, the
    * momenta of the components is properly set to the new values, whereas
    * we do not change the momenta of the pointed particles, because we
    * want to keep all of the information (that is the new momentum of a
    * component after the splitting, which is contained in the _momentum
    * member of the Component class, and the (old) momentum of that component
    * before the splitting, which is contained in the momentum of the
    * pointed particle). Please not make confusion of this only apparent
    * inconsistency!
    ********************/
   LorentzPoint posC,pos1,pos2;
   posC = cluster->vertex();
   calculatePositions(pClu, posC, pClu1, pClu2, pos1, pos2);
   cutType rval;
   if(toHadron1) {
     rval.first = produceHadron(toHadron1, newPtr1, pClu1, pos1);
     finalhadrons.push_back(rval.first.first);
   }
   else {
     rval.first = produceCluster(ptrQ1, newPtr1, pClu1, pos1, pQ1, pQone, rem1);
   }
   if(toHadron2) {
     rval.second = produceHadron(toHadron2, newPtr2, pClu2, pos2);
     finalhadrons.push_back(rval.second.first);
   }
   else {
     rval.second = produceCluster(ptrQ2, newPtr2, pClu2, pos2, pQ2, pQtwo, rem2);
   }
   return rval;
 }
 
 
 ClusterFissioner::cutType
 ClusterFissioner::cutThree(ClusterPtr & cluster, tPVector & finalhadrons,
 			   bool softUEisOn) {
   // need to make sure only 3-cpt clusters get here
   assert(cluster->numComponents() == 3);
   // extract quarks
   tPPtr ptrQ[3] = {cluster->particle(0),cluster->particle(1),cluster->particle(2)};
   assert( ptrQ[0] && ptrQ[1] && ptrQ[2] );
   // find maximum mass pair
   Energy mmax(ZERO);
   Lorentz5Momentum pDiQuark;
   int iq1(-1),iq2(-1);
   Lorentz5Momentum psum;
   for(int q1=0;q1<3;++q1) {
     psum+= ptrQ[q1]->momentum();
     for(int q2=q1+1;q2<3;++q2) {
       Lorentz5Momentum ptest = ptrQ[q1]->momentum()+ptrQ[q2]->momentum();
       ptest.rescaleMass();
       Energy mass = ptest.m();
       if(mass>mmax) {
 	mmax = mass;
 	pDiQuark = ptest;
 	iq1  = q1;
 	iq2  = q2;
       }
     }
   }
   // and the spectators
   int iother(-1);
   for(int ix=0;ix<3;++ix) if(ix!=iq1&&ix!=iq2) iother=ix;
   assert(iq1>=0&&iq2>=0&&iother>=0);
 
   // And check if those particles are from a beam remnant
   bool rem1 = cluster->isBeamRemnant(iq1);
   bool rem2 = cluster->isBeamRemnant(iq2);
   // workout which distribution to use
   bool soft1(false),soft2(false);
   switch (_iopRem) {
   case 0:
     soft1 = rem1 || rem2;
     soft2 = rem2 || rem1;
     break;
   case 1:
     soft1 = rem1;
     soft2 = rem2;
     break;
   }
   // Initialization for the exponential ("soft") mass distribution.
   static const int max_loop = 1000;
   int counter = 0;
   Energy Mc1 = ZERO, Mc2 = ZERO, m1=ZERO, m2=ZERO, m=ZERO;
   tcPDPtr toHadron;
   bool toDiQuark(false);
   PPtr newPtr1 = PPtr(),newPtr2 = PPtr();
   PDPtr diquark;
   bool succeeded = false;
   Lorentz5Momentum pClu1, pClu2, pQ1, pQone, pQtwo, pQ2;
   do {
     succeeded = false;
     ++counter;
 
     // get a flavour for the qqbar pair
     drawNewFlavour(newPtr1,newPtr2,cluster);
     
     // randomly pick which will be (anti)diquark and which a mesonic cluster
     if(UseRandom::rndbool()) {
       swap(iq1,iq2);
       swap(rem1,rem2);
     }
     // check first order
     if(cantMakeHadron(ptrQ[iq1], newPtr1) || !spectrum()->canMakeDiQuark(ptrQ[iq2], newPtr2)) {
       swap(newPtr1,newPtr2);
     }
     // check again
     if(cantMakeHadron(ptrQ[iq1], newPtr1) || !spectrum()->canMakeDiQuark(ptrQ[iq2], newPtr2)) {
       throw Exception()
 	<< "ClusterFissioner cannot split the cluster ("
 	<< ptrQ[iq1]->PDGName() << ' ' << ptrQ[iq2]->PDGName()
 	<< ") into a hadron and diquark.\n" << Exception::runerror;
     }
     // Check that new clusters can produce particles and there is enough
     // phase space to choose the drawn flavour
     m1 = ptrQ[iq1]->data().constituentMass();
     m2 = ptrQ[iq2]->data().constituentMass();
     m  = newPtr1->data().constituentMass();
     // Do not split in the case there is no phase space available
     if(mmax <  m1+m + m2+m) continue;
 
     pQ1.setMass(m1);
     pQone.setMass(m);
     pQtwo.setMass(m);
     pQ2.setMass(m2);
 
     pair<Energy,Energy> res = drawNewMasses(mmax, soft1, soft2, pClu1, pClu2,
 					    ptrQ[iq1], pQ1, newPtr1, pQone,
 					    newPtr2, pQtwo, ptrQ[iq1], pQ2);
 
     Mc1 = res.first; Mc2 = res.second;
 
     if(Mc1 < m1+m || Mc2 < m+m2 || Mc1+Mc2 > mmax) continue;
 
     if ( _phaseSpaceWeights ) {
 		if ( phaseSpaceVeto(mmax,Mc1,Mc2,m,m1,m2) )
 			continue;
     }
     
     // check if need to force meson clster to hadron
     toHadron = _hadronSpectrum->chooseSingleHadron(ptrQ[iq1]->dataPtr(), newPtr1->dataPtr(),Mc1);
     if(toHadron) { Mc1 = toHadron->mass(); pClu1.setMass(Mc1); }
     // check if need to force diquark cluster to be on-shell
     toDiQuark = false;
     diquark = spectrum()->makeDiquark(ptrQ[iq2]->dataPtr(), newPtr2->dataPtr());
     if(Mc2 < diquark->constituentMass()) {
       Mc2 = diquark->constituentMass(); pClu2.setMass(Mc2);
       toDiQuark = true;
     }
     // if a beam cluster not allowed to decay to hadrons
     if(cluster->isBeamCluster() && toHadron && softUEisOn)
       continue;
     // Check if the decay kinematics is still possible: if not then
     // force the one-hadron decay for the other cluster as well.
     if(Mc1 + Mc2  >  mmax) {
       if(!toHadron) {
 	toHadron = _hadronSpectrum->chooseSingleHadron(ptrQ[iq1]->dataPtr(), newPtr1->dataPtr(),mmax-Mc2);
 	if(toHadron) { Mc1 = toHadron->mass(); pClu1.setMass(Mc1); }
       }
       else if(!toDiQuark) {
 	Mc2 = _hadronSpectrum->massLightestHadron(ptrQ[iq2]->dataPtr(), newPtr2->dataPtr()); pClu2.setMass(Mc2);
 	toDiQuark = true;
       }
     }
     succeeded = (mmax >= Mc1+Mc2);
   }
   while (!succeeded && counter < max_loop);
   // check no of tries
   if(counter >= max_loop) return cutType();
 
   // Determine the (5-components) momenta (all in the LAB frame)
   Lorentz5Momentum p0Q1 = ptrQ[iq1]->momentum();
   calculateKinematics(pDiQuark,p0Q1,toHadron,toDiQuark,
 		      pClu1,pClu2,pQ1,pQone,pQtwo,pQ2);
   // positions of the new clusters
   LorentzPoint pos1,pos2;
   Lorentz5Momentum pBaryon = pClu2+ptrQ[iother]->momentum();
   calculatePositions(cluster->momentum(), cluster->vertex(), pClu1, pBaryon, pos1, pos2);
   // first the mesonic cluster/meson
   cutType rval;
    if(toHadron) {
      rval.first = produceHadron(toHadron, newPtr1, pClu1, pos1);
      finalhadrons.push_back(rval.first.first);
    }
    else {
      rval.first = produceCluster(ptrQ[iq1], newPtr1, pClu1, pos1, pQ1, pQone, rem1);
    }
    if(toDiQuark) {
      rem2 |= cluster->isBeamRemnant(iother);
      PPtr newDiQuark = diquark->produceParticle(pClu2);
      rval.second = produceCluster(newDiQuark, ptrQ[iother], pBaryon, pos2, pClu2,
       				  ptrQ[iother]->momentum(), rem2);
    }
    else {
      rval.second = produceCluster(ptrQ[iq2], newPtr2, pBaryon, pos2, pQ2, pQtwo, rem2,
 				  ptrQ[iother],cluster->isBeamRemnant(iother));
    }
    cluster->isAvailable(false);
    return rval;
 }
 
 ClusterFissioner::PPair
 ClusterFissioner::produceHadron(tcPDPtr hadron, tPPtr newPtr, const Lorentz5Momentum &a,
 				const LorentzPoint &b) const {
   PPair rval;
   if(hadron->coloured()) {
     rval.first = (_hadronSpectrum->lightestHadron(hadron,newPtr->dataPtr()))->produceParticle();
   }
   else
     rval.first = hadron->produceParticle();
   rval.second = newPtr;
   rval.first->set5Momentum(a);
   rval.first->setVertex(b);
   return rval;
 }
 
 ClusterFissioner::PPair ClusterFissioner::produceCluster(tPPtr ptrQ, tPPtr newPtr,
 							 const Lorentz5Momentum & a,
 				                         const LorentzPoint & b,
 							 const Lorentz5Momentum & c,
 				                         const Lorentz5Momentum & d,
 							 bool isRem,
 							 tPPtr spect, bool remSpect) const {
   PPair rval;
   rval.second = newPtr;
   ClusterPtr cluster = !spect ? new_ptr(Cluster(ptrQ,rval.second)) : new_ptr(Cluster(ptrQ,rval.second,spect));
   rval.first = cluster;
   cluster->set5Momentum(a);
   cluster->setVertex(b);
   assert(cluster->particle(0)->id() == ptrQ->id());
   cluster->particle(0)->set5Momentum(c);
   cluster->particle(1)->set5Momentum(d);
   cluster->setBeamRemnant(0,isRem);
   if(remSpect) cluster->setBeamRemnant(2,remSpect);
   return rval;
 }
 void ClusterFissioner::drawNewFlavourDiquarks(PPtr& newPtrPos,PPtr& newPtrNeg,
 		const ClusterPtr & clu) const {
 
   // Flavour is assumed to be only  u, d, s,  with weights
   // (which are not normalized probabilities) given
   // by the same weights as used in HadronsSelector for
   // the decay of clusters into two hadrons.
 
   unsigned hasDiquarks=0;
   assert(clu->numComponents()==2);
   tcPDPtr pD1=clu->particle(0)->dataPtr();
   tcPDPtr pD2=clu->particle(1)->dataPtr();
   bool isDiq1=DiquarkMatcher::Check(pD1->id());
   if (isDiq1) hasDiquarks++;
   bool isDiq2=DiquarkMatcher::Check(pD2->id());
   if (isDiq2) hasDiquarks++;
   assert(hasDiquarks<=2);
   Energy Mc=(clu->momentum().mass());
   // if (fabs(clu->momentum().massError() )>1e-14) std::cout << "Mass inconsistency CF : " << std::scientific  << clu->momentum().massError() <<"\n";
   // Not allow yet Diquark Clusters 
   // if ( hasDiquarks>=1 || Mc < spectrum()->massLightestBaryonPair(pD1,pD2) )
 	  // return drawNewFlavour(newPtrPos,newPtrNeg);
 
   Energy minMass;
   Selector<long> choice;
   // int countQ=0;
   // int countDiQ=0;
   // adding quark-antiquark pairs to the selection list
   for ( const long& id : spectrum()->lightHadronizingQuarks() ) {
 	  // TODO uncommenting below gives sometimes 0 selection possibility,
 	  // maybe need to be checked in the LightClusterDecayer and ColourReconnector
 	  // if (Mc < spectrum()->massLightestHadronPair(pD1,pD2)) continue;
 	  // countQ++;
 	  if (_fissionCluster==0) choice.insert(_hadronSpectrum->pwtQuark(id),id);
 	  else if (_fissionCluster==1) choice.insert(_fissionPwt.find(id)->second,id);
 	  else assert(false);
   }
   // adding diquark-antidiquark pairs to the selection list
   switch (hasDiquarks)
   {
   	case 0:
 		for ( const long& id : spectrum()->lightHadronizingDiquarks() ) {
 			if (_strictDiquarkKinematics) {
 				tPDPtr cand = getParticleData(id);
 				minMass = spectrum()->massLightestHadron(pD2,cand)
 						+ spectrum()->massLightestHadron(cand,pD1);
 			}
 			else minMass = spectrum()->massLightestBaryonPair(pD1,pD2);
 			if (Mc < minMass) continue;
 			// countDiQ++;
 			if (_fissionCluster==0) choice.insert(_hadronSpectrum->pwtQuark(id),id);
 			else if (_fissionCluster==1) choice.insert(_fissionPwt.find(id)->second,id);
 			else assert(false);
 		}
   		break;
   	case 1:
 		if (_diquarkClusterFission<1) break;
 		for ( const long& id : spectrum()->lightHadronizingDiquarks() ) {
 			tPDPtr diq = getParticleData(id);
 			if (isDiq1)
 				minMass = spectrum()->massLightestHadron(pD2,diq)
 						+ spectrum()->massLightestBaryonPair(diq,pD1);
 			else
 				minMass = spectrum()->massLightestHadron(pD1,diq)
 						+ spectrum()->massLightestBaryonPair(diq,pD2);
 			if (Mc < minMass) continue;
 			// countDiQ++;
 			if (_fissionCluster==0) choice.insert(_hadronSpectrum->pwtQuark(id),id);
 			else if (_fissionCluster==1) choice.insert(_fissionPwt.find(id)->second,id);
 			else assert(false);
 		}
 		break;
   	case 2:
 		if (_diquarkClusterFission<2) break;
 		for ( const long& id : spectrum()->lightHadronizingDiquarks() ) {
 			tPDPtr diq = getParticleData(id);
 			if (Mc < spectrum()->massLightestBaryonPair(pD1,pD2)) {
 				throw Exception() << "Found Diquark Cluster:\n" << *clu << "\nwith  MassCluster = "
 					<< ounit(Mc,GeV) <<" GeV MassLightestBaryonPair = "
 					<< ounit(spectrum()->massLightestBaryonPair(pD1,pD2) ,GeV)
 					<< " GeV cannot decay" << Exception::eventerror;
 			}
 			minMass = spectrum()->massLightestBaryonPair(pD1,diq)
 					+ spectrum()->massLightestBaryonPair(diq,pD2);
 			if (Mc < minMass) continue;
 			// countDiQ++;
 			if (_fissionCluster==0) choice.insert(_hadronSpectrum->pwtQuark(id),id);
 			else if (_fissionCluster==1) choice.insert(_fissionPwt.find(id)->second,id);
 			else assert(false);
 		}
   		break;
   	default:
   		assert(false);
   }
   assert(choice.size()>0);
   long idNew = choice.select(UseRandom::rnd());
   newPtrPos = getParticle(idNew);
   newPtrNeg = getParticle(-idNew);
   assert (newPtrPos);
   assert(newPtrNeg);
   assert (newPtrPos->dataPtr());
   assert(newPtrNeg->dataPtr());
 
 }
 
 void ClusterFissioner::drawNewFlavour(PPtr& newPtrPos,PPtr& newPtrNeg) const {
 
   // Flavour is assumed to be only  u, d, s,  with weights
   // (which are not normalized probabilities) given
   // by the same weights as used in HadronsSelector for
   // the decay of clusters into two hadrons.
 
 
   Selector<long> choice;
   switch(_fissionCluster){
   case 0:
     for ( const long& id : spectrum()->lightHadronizingQuarks() )
       choice.insert(_hadronSpectrum->pwtQuark(id),id);
     break;
   case 1:
     for ( const long& id : spectrum()->lightHadronizingQuarks() )
       choice.insert(_fissionPwt.find(id)->second,id);
     break;
   default :
     assert(false);
   }
   long idNew = choice.select(UseRandom::rnd());
   newPtrPos = getParticle(idNew);
   newPtrNeg = getParticle(-idNew);
   assert (newPtrPos);
   assert(newPtrNeg);
   assert (newPtrPos->dataPtr());
   assert(newPtrNeg->dataPtr());
 
 }
 
 void ClusterFissioner::drawNewFlavourEnhanced(PPtr& newPtrPos,PPtr& newPtrNeg,
                                               Energy2 mass2) const {
 
   if ( spectrum()->gluonId() != ParticleID::g )
     throw Exception() << "strange enhancement only working with Standard Model hadronization"
 		      << Exception::runerror;
   
   // Flavour is assumed to be only  u, d, s,  with weights
   // (which are not normalized probabilities) given
   // by the same weights as used in HadronsSelector for
   // the decay of clusters into two hadrons.
 
     double prob_d = 0.;
     double prob_u = 0.;
     double prob_s = 0.;
     double scale = abs(double(sqr(_m0Fission)/mass2));
     // Choose which splitting weights you wish to use
 switch(_fissionCluster){
   // 0: ClusterFissioner and ClusterDecayer use the same weights
   case 0:
     prob_d = _hadronSpectrum->pwtQuark(ParticleID::d);
      prob_u = _hadronSpectrum->pwtQuark(ParticleID::u);
      /* Strangeness enhancement:
         Case 1: probability scaling
         Case 2: Exponential scaling
      */
      if (_enhanceSProb == 1)
         prob_s = (_maxScale < scale) ? 0. : pow(_hadronSpectrum->pwtQuark(ParticleID::s),scale);
      else if (_enhanceSProb == 2)
         prob_s = (_maxScale < scale) ? 0. : exp(-scale);
     break;
     /* 1: ClusterFissioner uses its own unique set of weights,
        i.e. decoupled from ClusterDecayer */
   case 1:
     prob_d = _fissionPwt.find(ParticleID::d)->second;
     prob_u = _fissionPwt.find(ParticleID::u)->second;
      if (_enhanceSProb == 1)
        prob_s = (_maxScale < scale) ? 0. : pow(_fissionPwt.find(ParticleID::s)->second,scale);
      else if (_enhanceSProb == 2)
         prob_s = (_maxScale < scale) ? 0. : exp(-scale);
     break;
   default:
     assert(false);
   }
 
   int choice = UseRandom::rnd3(prob_u, prob_d, prob_s);
   long idNew = 0;
   switch (choice) {
   case 0: idNew = ThePEG::ParticleID::u; break;
   case 1: idNew = ThePEG::ParticleID::d; break;
   case 2: idNew = ThePEG::ParticleID::s; break;
   }
   newPtrPos = getParticle(idNew);
   newPtrNeg = getParticle(-idNew);
   assert (newPtrPos);
   assert(newPtrNeg);
   assert (newPtrPos->dataPtr());
   assert(newPtrNeg->dataPtr());
 
 }
 
 
 Energy2 ClusterFissioner::clustermass(const ClusterPtr & cluster) const {
   Lorentz5Momentum pIn = cluster->momentum();
   Energy2 endpointmass2 = sqr(cluster->particle(0)->mass() +
   cluster->particle(1)->mass());
   Energy2 singletm2 = pIn.m2();
   // Return either the cluster mass, or the lambda measure
   return (_massMeasure == 0) ? singletm2 : singletm2 - endpointmass2;
 }
 
 
 Energy ClusterFissioner::drawChildMass(const Energy M, const Energy m1,
 				       const Energy m2, const Energy m,
 				       const double expt, const bool soft) const {
 
   /***************************
    * This method, given in input the cluster mass Mclu of an heavy cluster C,
    * made of consituents of masses m1 and m2, draws the masses Mclu1 and Mclu2
    * of, respectively, the children cluster C1, made of constituent masses m1
    * and m, and cluster C2, of mass Mclu2 and made of constituent masses m2
    * and m. The mass is extracted from one of the two following mass
    * distributions:
    *   --- power-like ("normal" distribution)
    *                        d(Prob) / d(M^exponent) = const
    *       where the exponent can be different from the two children C1 (exp1)
    *       and C2 (exponent2).
    *   --- exponential ("soft" distribution)
    *                        d(Prob) / d(M^2) = exp(-b*M)
    *       where b = 2.0 / average.
    * Such distributions are limited below by the masses of
    * the constituents quarks, and above from the mass of decaying cluster C.
    * The choice of which of the two mass distributions to use for each of the
    * two cluster children is dictated by  iRemnant  (see below).
    * If the number of attempts to extract a pair of mass values that are
    * kinematically acceptable is above some fixed number (max_loop, see below)
    * the method gives up and returns false; otherwise, when it succeeds, it
    * returns true.
    *
    * These distributions have been modified from HERWIG:
    * Before these were:
    *      Mclu1 = m1 + (Mclu - m1 - m2)*pow( rnd(), 1.0/exponent1 );
    * The new one coded here is a more efficient version, same density
    * but taking into account 'in phase space from' beforehand
    ***************************/
   // hard cluster
   if(!soft) {
     return pow(UseRandom::rnd(pow((M-m1-m2-m)*UnitRemoval::InvE, expt),
 			      pow(m*UnitRemoval::InvE, expt)), 1./expt
 	       )*UnitRemoval::E + m1;
   }
   // Otherwise it uses a soft mass distribution
   else {
     static const InvEnergy b = 2.0 / _btClM;
     Energy max = M-m1-m2-2.0*m;
     double rmin = b*max;
     rmin = ( rmin < 50 ) ? exp(-rmin) : 0.;
     double r1;
     do {
       r1 = UseRandom::rnd(rmin, 1.0) * UseRandom::rnd(rmin, 1.0);
     }
     while (r1 < rmin);
     return m1 + m - log(r1)/b;
   }
 }
 
 Axis ClusterFissioner::sampleDirectionAligned(const Lorentz5Momentum & pRelCOM) const {
 	return pRelCOM.vect().unit();
 }
 
 Axis ClusterFissioner::sampleDirectionUniform() const {
   double cosTheta = -1 + 2.0 * UseRandom::rnd();
   double sinTheta = sqrt(1.0-cosTheta*cosTheta);
   double Phi = 2.0 * Constants::pi * UseRandom::rnd();
   Axis uClusterUniform(cos(Phi)*cosTheta, sin(Phi)*cosTheta, sinTheta);
   return uClusterUniform.unit();
 }
 
 Axis ClusterFissioner::sampleDirectionGaussianPT(const Lorentz5Momentum & pRelCOM,
 		const Energy Mass, const Energy mass1, const Energy mass2) const {
 	Energy pstarCOM = Kinematics::pstarTwoBodyDecay(Mass,mass1,mass2);
 	Energy pTx;
 	Energy pTy;
 	Energy2 pT2;
 	const int maxcount=100;
 	int count=0;
 	Energy sigmaPT=_fluxTubeWidth;
 	do {
 		if (count>=maxcount) {
 			if (pstarCOM>0.5*sigmaPT) throw Exception() << "Could not sample direction in ClusterFissioner::sampleDirectionGaussianPT() "
 				<< Exception::eventerror;
 			// Fallback uniform sampling
 			double phi=UseRandom::rnd()*Constants::pi;
 			Energy magnitude=UseRandom::rnd()*pstarCOM;
 			pTx = magnitude*cos(phi);
 			pTy = magnitude*sin(phi);
 			pT2 = sqr(pTx)+sqr(pTy);
 			break;
 		}
 		pTx = UseRandom::rndGauss(sigmaPT);
 		pTy = UseRandom::rndGauss(sigmaPT);
 		pT2 = sqr(pTx)+sqr(pTy);
 		count++;
 	}
 	while (pT2>sqr(pstarCOM));
 	Axis pRelativeDir=pRelCOM.vect().unit();
 
 	Axis TrvX = pRelativeDir.orthogonal().unit();
 	Axis TrvY = TrvX.cross(pRelativeDir).unit();
 	Axis pTkick = pTx/pstarCOM*TrvX + pTy/pstarCOM*TrvY;
 	Axis uClusterFluxTube = (pRelativeDir*sqrt(1.0-pT2/sqr(pstarCOM)) + pTkick);
 	return uClusterFluxTube.unit();
 }
+static void printVec(const Lorentz5Momentum & p);
+static void printVec(const Lorentz5Momentum & p){
+  std::cout << "( "
+	  << p.t()/GeV << ",\t"
+	  << p.vect().x()/GeV << ",\t"
+	  << p.vect().y()/GeV << ",\t"
+	  << p.vect().z()/GeV
+	  << " )\t|p| = "
+	  << sqrt(sqr(p.vect())/GeV2) <<"\tm = "
+	  << p.m()/GeV <<"\tmass = "
+	  << p.mass()/GeV <<"\n";
+}
 
+// static void printVecBoost(const boost::numeric::ublas::vector<Energy> & p);
+// static void printVecBoost(const boost::numeric::ublas::vector<Energy> & p){
+  // std::cout << "( "
+	  // << p[0]/GeV << ",\t"
+	  // << p[1]/GeV << ",\t"
+	  // << p[2]/GeV << ",\t"
+	  // << p[3]/GeV
+	  // << " )\t|p| = "
+	  // << sqrt(sqr(p[1]*p[1]+p[2]*p[2]+p[3]*p[3])/GeV2) <<"\tmass = "
+	  // << sqrt(sqr(p[0]*p[0]-(p[1]*p[1]+p[2]*p[2]+p[3]*p[3]))/GeV2) <<"\n";
+// }
+
+static void printVecBoostDBL(const boost::numeric::ublas::vector<double> & p);
+static void printVecBoostDBL(const boost::numeric::ublas::vector<double> & p){
+  std::cout << "( "
+	  << p[0] << ",\t"
+	  << p[1] << ",\t"
+	  << p[2] << ",\t"
+	  << p[3]
+	  << " )\t|p| = "
+	  << sqrt(p[1]*p[1]+p[2]*p[2]+p[3]*p[3]) <<"\tmass = "
+	  << sqrt(p[0]*p[0]-(p[1]*p[1]+p[2]*p[2]+p[3]*p[3])) <<"\n";
+}
 void ClusterFissioner::calculateKinematics(const Lorentz5Momentum & pClu,
 					   const Lorentz5Momentum & p0Q1,
 					   const bool toHadron1,
 					   const bool toHadron2,
 					   Lorentz5Momentum & pClu1,
 					   Lorentz5Momentum & pClu2,
 					   Lorentz5Momentum & pQ1,
 					   Lorentz5Momentum & pQbar,
 					   Lorentz5Momentum & pQ,
 					   Lorentz5Momentum & pQ2bar) const {
 
   /******************
    * This method solves the kinematics of the two body cluster decay:
    *    C (Q1 Q2bar)  --->  C1 (Q1 Qbar)  +  C2 (Q Q2bar)
    * In input we receive the momentum of C, pClu, and the momentum
    * of the quark Q1 (constituent of C), p0Q1, both in the LAB frame.
    * Furthermore, two boolean variables inform whether the two fission
    * products (C1, C2) decay immediately into a single hadron (in which
    * case the cluster itself is identify with that hadron) and we do
    * not have to solve the kinematics of the components (Q1,Qbar) for
    * C1 and (Q,Q2bar) for C2.
    * The output is given by the following momenta (all 5-components,
    * and all in the LAB frame):
    *   pClu1 , pClu2   respectively of   C1 , C2
    *   pQ1 , pQbar     respectively of   Q1 , Qbar  in  C1
    *   pQ  , pQ2bar    respectively of   Q  , Q2    in  C2
    * The assumption, suggested from the string model, is that, in C frame,
    * C1 and its constituents Q1 and Qbar are collinear, and collinear to
    * the direction of Q1 in C (that is before cluster decay); similarly,
    * (always in the C frame) C2 and its constituents Q and Q2bar are
    * collinear (and therefore anti-collinear with C1,Q1,Qbar).
    * The solution is then obtained by using Lorentz boosts, as follows.
    * The kinematics of C1 and C2 is solved in their parent C frame,
    * and then boosted back in the LAB. The kinematics of Q1 and Qbar
    * is solved in their parent C1 frame and then boosted back in the LAB;
    * similarly, the kinematics of Q and Q2bar is solved in their parent
    * C2 frame and then boosted back in the LAB. In each of the three
    * "two-body decay"-like cases, we use the fact that the direction
    * of the motion of the decay products is known in the rest frame of
    * their parent. This is obvious for the first case in which the
    * parent rest frame is C; but it is also true in the other two cases
    * where the rest frames are C1 and C2. This is because C1 and C2
    * are boosted w.r.t. C in the same direction where their components,
    * respectively (Q1,Qbar) and (Q,Q2bar) move in C1 and C2 rest frame
    * respectively.
    * Of course, although the notation used assumed that C = (Q1 Q2bar)
    * where Q1 is a quark and Q2bar an antiquark, indeed everything remain
    * unchanged also in all following cases:
    *  Q1 quark, Q2bar antiquark;           --> Q quark;
    *  Q1 antiquark , Q2bar quark;          --> Q antiquark;
    *  Q1 quark, Q2bar diquark;             --> Q quark
    *  Q1 antiquark, Q2bar anti-diquark;    --> Q antiquark
    *  Q1 diquark, Q2bar quark              --> Q antiquark
    *  Q1 anti-diquark, Q2bar antiquark;    --> Q quark
    **************************/
 
 
   if (pClu.m() < pClu1.mass() + pClu2.mass()
 		  || pClu1.mass()<ZERO
 		  || pClu2.mass()<ZERO  ) {
     throw Exception() << "Impossible Kinematics in ClusterFissioner::calculateKinematics[FluxTube]() (A)"
 		      << Exception::eventerror;
   }
+  // INTERLUDE TODO:
+  Axis zAxis(0,0,1);
+  Axis xAxis(1,0,0);
+
+  // Energy Pcom=Kinematics::pstarTwoBodyDecay(pClu.m(),pClu1.mass(),pClu2.mass());
+  std::cout << "deltaMsqr = " << (pClu.m()-sqrt(sqr(pClu)))/GeV << std::endl;
+  std::cout << "deltaMass = " << (pClu.mass()-sqrt(sqr(pClu)))/GeV << std::endl;
+  Lorentz5Momentum pivector(p0Q1);
+  Lorentz5Momentum pjvector(pClu-p0Q1);
+  Energy Ei=sqrt(pQ1.mass()*pQ1.mass()+sqr(pivector.vect()));
+  Energy Ej=sqrt(pQ2bar.mass()*pQ2bar.mass()+sqr(pjvector.vect()));
+  double phi=acos(pivector.vect().unit()*pjvector.vect().unit());
+  Energy2 Ei2=Ei*Ei;
+  Energy2 Ej2=Ej*Ej;
+  Energy mi=pQ1.mass();
+  Energy mj=pQ2bar.mass();
+  std::cout << "mi = " << (mi)/GeV << std::endl;
+  std::cout << "mj = " << (mj)/GeV << std::endl;
+  Energy2 mi2=mi*mi;
+  Energy2 mj2=mj*mj;
+  Energy Pi=sqrt(Ei2-mi2);
+  Energy Pj=sqrt(Ej2-mj2);
+  Lorentz5Momentum pi(Pi*zAxis,Ei);
+  Lorentz5Momentum pj(Pj*(xAxis*sin(phi)+zAxis*cos(phi)),Ej);
+  pi.setMass(mi);
+  pj.setMass(mj);
+  Lorentz5Momentum pitmp(pi);
+  Lorentz5Momentum pjtmp(pj);
+  Energy2 pipj=pitmp*pjtmp;
+  std::cout << "pQ1.m() = "<<pQ1.m()/GeV << "pQ1.mass() = "<<pQ1.mass()/GeV << std::endl;
+  std::cout << "pQ2bar.m() = "<<pQ2bar.m()/GeV << "pQ2bar.mass() = "<<pQ2bar.mass()/GeV << std::endl;
+
+
+  std::cout << "PI : " << std::endl;
+  printVec(pi);
+  std::cout << "PJ : " << std::endl;
+  printVec(pj);
+  std::cout << "##################" << std::endl;
+
+
+
+  boost::numeric::ublas::matrix<double> Lambda(4,4);
+  
+  Energy sqrtS=sqrt(mi2+mj2+2*pipj);
+  Energy4 A4=(pipj*pipj-mi2*mj2);
+  Energy4 B4=-(Ej2*mi2+Ei2*mj2-mi2*mj2-2*Ei*Ej*pipj+pipj*pipj);
+  std::cout << "A4 = "<<A4/(GeV2*GeV2) << std::endl;
+  std::cout << "B4 = "<<B4/(GeV2*GeV2) << std::endl;
+  std::cout << "sqrtS = "<<(sqrtS)/(GeV) << std::endl;
+  std::cout << "pClu.mass() = "<<(pClu.mass())/(GeV) << std::endl;
+  std::cout << "pClu.mass() = "<<sqrt(sqr(pClu)/(GeV2)) << std::endl;
+  std::cout << "pipj = "<<(pipj)/(GeV2) << std::endl;
+  std::cout << "pipj dotted = "<<(pi.dot(pj))/(GeV2) << std::endl;
+  std::cout << "pipj should be = "<<(sqrtS*sqrtS-mi2-mj2)/(2*GeV2) << std::endl;
+  Energy2 A2=sqrt(A4);
+  Energy2 B2=sqrt(B4);
+
+  Lambda(0,0) = (Ei+Ej)/sqrtS;
+  Lambda(0,1) = B2/A2;
+  Lambda(0,2) = 0;
+  Lambda(0,3) = (Ei*(mj2+pipj)-Ej*(mi2+pipj))/(sqrtS*A2);
+
+  Lambda(1,0) = B2/(Pi*sqrtS);
+  Lambda(1,1) = (Ei*pipj-Ej*mi2)/(Pi*A2);
+  Lambda(1,2) = 0;
+  Lambda(1,3) = -(mi2+pipj)*B2/(Pi*sqrtS*A2);
+
+  Lambda(2,0) = 0;
+  Lambda(2,1) = 0;
+  Lambda(2,2) = 1;
+  Lambda(2,3) = 0;
+
+  Lambda(3,0) = (Ei2+Ei*Ej-mi2-pipj)/(Pi*sqrtS);
+  Lambda(3,1) = -Ei*B2/(Pi*A2);
+  Lambda(3,2) = 0;
+  Lambda(3,3) = (pipj*pipj-mi2*mj2-Ei*Ej*(mi2+pipj)+Ei2*(mj2+pipj))/(Pi*sqrtS*A2);
+
+  double det=0;
+  det += Lambda(0,0)*Lambda(1,1)*Lambda(3,3);
+  det += Lambda(1,0)*Lambda(3,1)*Lambda(0,3);
+  det += Lambda(3,0)*Lambda(0,1)*Lambda(1,3);
+
+  det -= Lambda(0,3)*Lambda(1,1)*Lambda(3,0);
+  det -= Lambda(1,0)*Lambda(0,1)*Lambda(3,3);
+  det -= Lambda(1,3)*Lambda(3,1)*Lambda(0,0);
+  std::cout << "DET = "<< det << std::endl;
+
+  boost::numeric::ublas::vector<double> PvecHati(4);
+  boost::numeric::ublas::vector<double> PvecHatj(4);
+
+
+  
+  Energy Pcom=Kinematics::pstarTwoBodyDecay(pClu.mass(),pQ1.mass(),pQ2bar.mass());
+  PvecHati[0]=sqrt(mi2+Pcom*Pcom)/GeV;
+  PvecHati[1]=0;
+  PvecHati[2]=0;
+  PvecHati[3]=Pcom/GeV;
+
+  PvecHatj[0]=sqrt(mj2+Pcom*Pcom)/GeV;
+  PvecHatj[1]=0;
+  PvecHatj[2]=0;
+  PvecHatj[3]=-Pcom/GeV;
+
+
+  std::cout << "piHat before : \n";
+  printVecBoostDBL(PvecHati);
+  std::cout << "pjHat before : \n";
+  printVecBoostDBL(PvecHatj);
+
+
+
+  std::cout << "Lambda:" << std::endl;
+  for (int i = 0; i < 4; i++)
+  {
+  	for (int j = 0; j < 4; j++)
+  	{
+  		std::cout << Lambda(i,j) << "\t";
+  	}
+  	std::cout << "\n";
+  }
+
+  // boost::numeric::ublas::vector<Energy> Pveci(4);
+  // boost::numeric::ublas::vector<Energy> Pvecj(4);
+  auto Pveci=boost::numeric::ublas::prod(Lambda,PvecHati);
+  auto Pvecj=boost::numeric::ublas::prod(Lambda,PvecHatj);
+  std::cout << "pi after : \n";
+  printVecBoostDBL(Pveci);
+  std::cout << "pj after : \n";
+  printVecBoostDBL(Pvecj);
+
+  std::cout << "pi should be : \n";
+  printVec(pi);
+  std::cout << "pj should be : \n";
+  printVec(pj);
+
+  // Lorentz5Momentum pi(pQ2bar.mass(),(pClu-p0Q1).vect());
+  // Lorentz5Momentum pj(pQ1.mass(),p0Q1.vect());
+
+
+
+  // std::cout << "pi before : \n";
+  // printVec(pi);
+  // std::cout << "pj before : \n";
+  // printVec(pj);
+
+  // pi.boost(-pClu.boostVector());
+  // pj.boost(-pClu.boostVector());
+
+  // pi.boost(pClu.boostVector());
+  // pj.boost(pClu.boostVector());
+
+  // std::cout << "pi after : \n";
+  // printVec(pi);
+  // std::cout << "pj after : \n";
+  // printVec(pj);
+  // Axis zax(0,0,1);
+  // Energy Pcom=Kinematics::pstarTwoBodyDecay(pClu.m(),pClu1.mass(),pClu2.mass());
+  // Energy Pcom=Kinematics::pstarTwoBodyDecay(pClu.m(),pQ1.mass(),pQ2bar.mass());
+  // Kinematics::twoBodyBoost(pi,pj,Pcom,zax);
+  // Lorentz5Momentum p0Q2_2(pClu-p0Q1);
+  // Lorentz5Momentum p0Q1_cp(p0Q1);
+  // Lorentz5Momentum prel1(pClu-2.0*p0Q1);
+  // Lorentz5Momentum prel2(pClu-2.0*p0Q1);
+  // Lorentz5Momentum ptot1(pClu);
+  // Lorentz5Momentum ptot2(pClu);
+
+  // ptot1.boost(-p0Q2_1.boostVector());
+  // prel1.boost(-p0Q2_1.boostVector());
+  // prel1.boost(-ptot1.boostVector());
+
+  // ptot2.boost(-p0Q1_cp.boostVector());
+  // prel2.boost(-p0Q1_cp.boostVector());
+
+  // ptot.boost(-prel.boostVector());
+  // prel.boost(-prel.boostVector());
+  // std::cout << "\nPrel in pRel frame: ( "
+	  // << prel.t()/GeV << ",\t"
+	  // << prel.vect().x()/GeV << ",\t"
+	  // << prel.vect().y()/GeV << ",\t"
+	  // << prel.vect().z()/GeV
+	  // << " )\n";
+  // std::cout << "Ptot in pRel frame: ( "
+	  // << ptot.t()/GeV << ",\t"
+	  // << ptot.vect().x()/GeV << ",\t"
+	  // << ptot.vect().y()/GeV << ",\t"
+	  // << ptot.vect().z()/GeV
+	  // << " )\n";
+  // prel.boost(-ptot.boostVector());
+  // ptot.boost(-ptot.boostVector());
+  // std::cout << "\nPrel in pTot frame: ( "
+	  // << prel.t()/GeV << ",\t"
+	  // << prel.vect().x()/GeV << ",\t"
+	  // << prel.vect().y()/GeV << ",\t"
+	  // << prel.vect().z()/GeV
+	  // << " )\n";
+  // std::cout << "Ptot in pTot frame: ( "
+	  // << ptot.t()/GeV << ",\t"
+	  // << ptot.vect().x()/GeV << ",\t"
+	  // << ptot.vect().y()/GeV << ",\t"
+	  // << ptot.vect().z()/GeV
+	  // << " )\n";
+  // ptot2.boost(-pClu.boostVector());
+  // prel2.boost(-pClu.boostVector());
+  // std::cout << "Ptot Naive in pTot frame: ( "
+	  // << ptot2.t()/GeV << ",\t"
+	  // << ptot2.vect().x()/GeV << ",\t"
+	  // << ptot2.vect().y()/GeV << ",\t"
+	  // << ptot2.vect().z()/GeV
+	  // << " )\n";
+  // std::cout << "Prel Naive in pTot frame: ( "
+	  // << prel2.t()/GeV << ",\t"
+	  // << prel2.vect().x()/GeV << ",\t"
+	  // << prel2.vect().y()/GeV << ",\t"
+	  // << prel2.vect().z()/GeV
+	  // << " )\n";
+
+
+  // END
 
   // Calculate the unit three-vector, in the Cluster frame,
   // using the sampling funtion sampleDirection in the respective
   // clusters rest frame
 
   // Calculate the momenta of C1 and C2 in the (parent) C frame first,
   // where the direction of C1 is samples according to sampleDirection,
   // and then boost back in the LAB frame.
   //
   // relative momentum in centre of mass of cluster
+  //  OLD
   Lorentz5Momentum uRelCluster(p0Q1);
   uRelCluster.boost( -pClu.boostVector() );        // boost from LAB to C
+  // NEW ? :
+  // Lorentz5Momentum uRelCluster(p0Q1);
+  // Lorentz5Momentum pCluTmp(pClu);
+  // uRelCluster.boost(-p0Q1.boostVector());
+  // pCluTmp.boost(-p0Q1.boostVector());
+  // uRelCluster.boost(-pCluTmp.boostVector());
 
   // sample direction (options = Default(aligned), Isotropic
   // or FluxTube(gaussian pT kick))
   const Axis DirClu = sampleDirection(uRelCluster,
 		  pClu.mass(), pClu1.mass(), pClu2.mass());
 
   Kinematics::twoBodyDecay(pClu, pClu1.mass(), pClu2.mass(),
 		  DirClu, pClu1, pClu2);
 
   // In the case that cluster1 does not decay immediately into a single hadron,
   // calculate the momenta of Q1 (as constituent of C1) and Qbar in the
   // (parent) C1 frame first, where the direction of Q1 is u.vect().unit(),
   // and then boost back in the LAB frame.
   if(!toHadron1) {
 	  if (pClu1.m() < pQ1.mass() + pQbar.mass() ) {
 		  throw Exception() << "Impossible Kinematics in ClusterFissioner::calculateKinematics[FluxTube]() (B)"
 			  << Exception::eventerror;
 	  }
 	  // sample direction (options = Default(aligned), Isotropic
 	  // or FluxTube(gaussian pT kick))
 	  // Axis DirClu1 = sampleDirection(uRelCluster,
 			  // pClu1.mass(), pQ1.mass(), pQbar.mass());
 
 	  Kinematics::twoBodyDecay(pClu1, pQ1.mass(), pQbar.mass(),
 			  DirClu, pQ1, pQbar);
   }
 
   // In the case that cluster2 does not decay immediately into a single hadron,
   // Calculate the momenta of Q and Q2bar (as constituent of C2) in the
   // (parent) C2 frame first, where the direction of Q is u.vect().unit(),
   // and then boost back in the LAB frame.
   if(!toHadron2) {
 	  if (pClu2.m() < pQ.mass() + pQ2bar.mass() ) {
 		  throw Exception() << "Impossible Kinematics in ClusterFissioner::calculateKinematics[FluxTube]() (C)"
 			  << Exception::eventerror;
 	  }
 	  // sample direction (options = Default(aligned), Isotropic
 	  // or FluxTube(gaussian pT kick))
 	  // Axis DirClu2 = sampleDirection(uRelCluster,
 			  // pClu2.mass(), pQ2bar.mass(), pQ.mass());
 
 	  Kinematics::twoBodyDecay(pClu2, pQ.mass(), pQ2bar.mass(),
 			  DirClu, pQ, pQ2bar);
   }
 }
 
 
 void ClusterFissioner::calculatePositions(const Lorentz5Momentum & pClu,
 					  const LorentzPoint & positionClu,
 					  const Lorentz5Momentum & pClu1,
 					  const Lorentz5Momentum & pClu2,
 					  LorentzPoint & positionClu1,
 					  LorentzPoint & positionClu2) const {
   // Determine positions of cluster children.
   // See Marc Smith's thesis, page 127, formulas (4.122) and (4.123).
   Energy Mclu  = pClu.m();
   Energy Mclu1 = pClu1.m();
   Energy Mclu2 = pClu2.m();
 
   // Calculate the unit three-vector, in the C frame, along which
   // children clusters move.
   Lorentz5Momentum u(pClu1);
   u.boost( -pClu.boostVector() );        // boost from LAB to C frame
 
   // the unit three-vector is then  u.vect().unit()
 
   Energy pstarChild = Kinematics::pstarTwoBodyDecay(Mclu,Mclu1,Mclu2);
 
   // First, determine the relative positions of the children clusters
   // in the parent cluster reference frame.
 
   Energy2 mag2 = u.vect().mag2();
   InvEnergy fact = mag2>ZERO ? 1./sqrt(mag2) : 1./GeV;
 
   Length x1 = ( 0.25*Mclu + 0.5*( pstarChild + (sqr(Mclu2) - sqr(Mclu1))/(2.0*Mclu)))/_kappa;
   Length t1 = Mclu/_kappa - x1;
   LorentzDistance distanceClu1( x1 * fact * u.vect(), t1 );
 
   Length x2 = (-0.25*Mclu + 0.5*(-pstarChild + (sqr(Mclu2) - sqr(Mclu1))/(2.0*Mclu)))/_kappa;
   Length t2 = Mclu/_kappa + x2;
   LorentzDistance distanceClu2( x2 * fact * u.vect(), t2 );
 
   // Then, transform such relative positions from the parent cluster
   // reference frame to the Lab frame.
   distanceClu1.boost( pClu.boostVector() );
   distanceClu2.boost( pClu.boostVector() );
 
   // Finally, determine the absolute positions in the Lab frame.
   positionClu1 = positionClu + distanceClu1;
   positionClu2 = positionClu + distanceClu2;
 
 }
 
 bool ClusterFissioner::ProbablityFunction(double scale, double threshold) {
   double cut = UseRandom::rnd(0.0,1.0);
   return 1./(1.+pow(abs((threshold-_probShift)/scale),_probPowFactor)) > cut ? true : false;
 }
 
 bool ClusterFissioner::isHeavy(tcClusterPtr clu) {
   // particle data for constituents
   tcPDPtr cptr[3]={tcPDPtr(),tcPDPtr(),tcPDPtr()};
   for(size_t ix=0;ix<min(clu->numComponents(),3);++ix) {
     cptr[ix]=clu->particle(ix)->dataPtr();
   }
   // different parameters for exotic, bottom and charm clusters
   double clpow = !spectrum()->isExotic(cptr[0],cptr[1],cptr[1]) ? _clPowLight : _clPowExotic;
   Energy clmax = !spectrum()->isExotic(cptr[0],cptr[1],cptr[1]) ? _clMaxLight : _clMaxExotic;
   for ( const long& id : spectrum()->heavyHadronizingQuarks() ) {
     if ( spectrum()->hasHeavy(id,cptr[0],cptr[1],cptr[1]) ) {
       clpow = _clPowHeavy[id];
       clmax = _clMaxHeavy[id];
     }
   }
    // required test for SUSY clusters, since aboveCutoff alone
   // cannot guarantee (Mc > m1 + m2 + 2*m) in cut()
   static const Energy minmass
     = getParticleData(ParticleID::d)->constituentMass();
   bool aboveCutoff = false, canSplitMinimally = false;
   // static kinematic threshold
   if(_kinematicThresholdChoice == 0) {
     aboveCutoff = (
     	      pow(clu->mass()*UnitRemoval::InvE , clpow)
     	      >
     	      pow(clmax*UnitRemoval::InvE, clpow)
     	      + pow(clu->sumConstituentMasses()*UnitRemoval::InvE, clpow)
     	      );
 
     canSplitMinimally = clu->mass() > clu->sumConstituentMasses() + 2.0 * minmass;
   }
   // dynamic kinematic threshold
   else if(_kinematicThresholdChoice == 1) {
     //some smooth probablity function to create a dynamic thershold
     double scale     = pow(clu->mass()/GeV , clpow);
     double threshold = pow(clmax/GeV, clpow)
                      + pow(clu->sumConstituentMasses()/GeV, clpow);
     aboveCutoff = ProbablityFunction(scale,threshold);
 
     scale     = clu->mass()/GeV;
     threshold = clu->sumConstituentMasses()/GeV + 2.0 * minmass/GeV;
 
     canSplitMinimally = ProbablityFunction(scale,threshold);
   }
 
   return aboveCutoff && canSplitMinimally;
 }
diff --git a/Utilities/Kinematics.cc b/Utilities/Kinematics.cc
--- a/Utilities/Kinematics.cc
+++ b/Utilities/Kinematics.cc
@@ -1,119 +1,215 @@
 // -*- C++ -*-
 //
 // Kinematics.cc is a part of Herwig - A multi-purpose Monte Carlo event generator
 // Copyright (C) 2002-2019 The Herwig Collaboration
 //
 // Herwig is licenced under version 3 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 Kinematics class.
 //
 
 #include "Kinematics.h"
 #include <ThePEG/Vectors/Lorentz5Vector.h>
 #include <ThePEG/Vectors/LorentzVector.h>
 #include <ThePEG/Vectors/LorentzRotation.h>
 #include <ThePEG/Repository/EventGenerator.h>
 #include <ThePEG/Repository/CurrentGenerator.h>
 #include <ThePEG/EventRecord/Event.h>
 
 using namespace Herwig;
 using namespace ThePEG;
 
+
+static void printVec(const Lorentz5Momentum & p);
+static void printVec(const Lorentz5Momentum & p){
+  std::cout << "( "
+	  << p.t()/GeV << ",\t"
+	  << p.vect().x()/GeV << ",\t"
+	  << p.vect().y()/GeV << ",\t"
+	  << p.vect().z()/GeV
+	  << " )\t|p| = "
+	  << sqrt(sqr(p.vect())/GeV2) <<"\tmass = "
+	  << sqrt(sqr(p)/GeV2) <<"\n";
+}
+
+bool Kinematics::twoBodyBoost(Lorentz5Momentum & p1, 
+			Lorentz5Momentum & p2,
+			// Lorentz5Momentum & q1,
+			// Lorentz5Momentum & q2,
+			const Energy & Pcom,
+			const Axis & Dir) {
+	Lorentz5Momentum pTot(p1+p2);
+	Energy2 Msq=sqr(p1+p2);
+	Energy2 m1sq=sqr(p1);
+	Energy2 m2sq=sqr(p2);
+	Lorentz5Momentum q1(sqrt(m1sq),Pcom*Dir);
+	Lorentz5Momentum q2(sqrt(m2sq),-Pcom*Dir);
+	Energy2 p1p2=p1.dot(p2);
+	Energy2 p1q2=p1.dot(q2);
+	Energy2 p1q1=p1.dot(q1);
+	Energy2 p2q1=q1.dot(p2);
+	Energy2 p2q2=q2.dot(p2);
+	Lorentz5Momentum k;
+	Energy4 denom = (m1sq+m2sq+2*p1p2)*(m1sq+m2sq+2*p1p2+p1q1+p1q2+p2q1+p2q2);
+	if (denom==ZERO) std::cout << "ERROR denom==ZERO" << std::endl;
+	Energy4 A=m1sq*m1sq+m1sq*m2sq+2*p1p2*p1p2+(m1sq-m2sq)*p1q1+2*m1sq*p1q2+m1sq*p2q1-m2sq*p2q1+2*m1sq*p2q2;
+	double Lam=(A+p1p2*(3*m1sq+m2sq+2*p1q2+2*p2q2))/denom;
+	std::cout << "Lam = "<<Lam<<"\n";
+	k  = (Lam - 1.0)*p1;
+	k += (Lam      )*p2;
+	std::cout << "before k addition\n";
+	printVec(p1);
+	printVec(p2);
+	std::cout << "the k Vector\n";
+	printVec(k);
+	p1.boost(-pTot.boostVector());
+	p2.boost(-pTot.boostVector());
+	p1+=k;
+	p2-=k;
+	// p1=q1;
+	// p2=q2;
+	std::cout << "after k addition\n";
+	printVec(p1);
+	printVec(p2);
+	return true;
+}
+
+/*
+
+bool Kinematics::twoBodyBoost(Lorentz5Momentum & p1, 
+			Lorentz5Momentum & p2,
+			// Lorentz5Momentum & q1,
+			// Lorentz5Momentum & q2,
+			const Energy & Pcom,
+			const Axis & Dir) {
+	Lorentz5Momentum pTot(p1+p2);
+	Energy2 Msq=sqr(p1+p2);
+	Energy2 m1sq=sqr(p1);
+	Energy2 m2sq=sqr(p2);
+	Lorentz5Momentum q1(sqrt(m1sq),Pcom*Dir);
+	Lorentz5Momentum q2(sqrt(m2sq),-Pcom*Dir);
+	// Energy2 p1p2=p1.dot(p2);
+	Energy2 p1q2=p1.dot(q2);
+	Energy2 p1q1=p1.dot(q1);
+	Energy2 p2q1=q1.dot(p2);
+	Energy2 p2q2=q2.dot(p2);
+	Lorentz5Momentum k;
+	Energy2 denom = 2*(p1q1+p1q2+p2q1+p2q2-Msq);
+	if (denom==ZERO) std::cout << "ERROR denom==ZERO" << std::endl;
+	k  = p1*(m1sq-m2sq-Msq+2*(p1q2+p2q2))/denom;
+	k += p2*(m1sq-m2sq+Msq-2*(p1q1+p2q1))/denom;
+	k += q1*(m2sq-m1sq+Msq-2*(p1q2+p2q2))/denom;
+	k += q2*(m2sq-m1sq-Msq+2*(p1q1+p2q1))/denom;
+	std::cout << "before k addition\n";
+	printVec(q1);
+	printVec(q2);
+	std::cout << "the k Vector\n";
+	printVec(k);
+	p1-=k;
+	p2+=k;
+	// p1=q1;
+	// p2=q2;
+	std::cout << "after k addition\n";
+	printVec(p1);
+	printVec(p2);
+	return true;
+}*/
+
 bool Kinematics::twoBodyDecay(const Lorentz5Momentum & p, 
            const Energy m1, const Energy m2,
            const Axis & unitDir1,
            Lorentz5Momentum & p1, Lorentz5Momentum & p2) {
       Energy min=p.mass();
       if ( min >= m1 + m2  &&  m1 >= ZERO  &&  m2 >= ZERO  ) {
   Momentum3 pstarVector = unitDir1 * pstarTwoBodyDecay(min,m1,m2);
   p1 = Lorentz5Momentum(m1, pstarVector);
   p2 = Lorentz5Momentum(m2,-pstarVector);
   // boost from CM to LAB
   Boost bv = p.boostVector();
   double gammarest = p.e()/p.mass();
   p1.boost( bv, gammarest );
   p2.boost( bv, gammarest );
   return true;
       }
       return false;
     }
 
 /*****
  * This function, as the name implies, performs a three body decay. The decay
  * products are distributed uniformly in all three directions.
  ****/
 bool Kinematics::threeBodyDecay(Lorentz5Momentum p0, Lorentz5Momentum &p1, 
 				Lorentz5Momentum &p2, Lorentz5Momentum &p3,
 				double (*fcn)(Energy2,Energy2,Energy2,InvEnergy4)) {
   // Variables needed in calculation...named same as fortran version
   Energy a = p0.mass() + p1.mass();
   Energy b = p0.mass() - p1.mass();
   Energy c = p2.mass() + p3.mass();
   
   if(b < c) {
      CurrentGenerator::log() 
        << "Kinematics::threeBodyDecay() phase space problem\n"
        << p0.mass()/GeV << " -> "
        << p1.mass()/GeV << ' '
        << p2.mass()/GeV << ' '
        << p3.mass()/GeV << '\n';
      return false;
   }
   
   Energy d = abs(p2.mass()-p3.mass());
   Energy2 aa = sqr(a); 
   Energy2 bb = sqr(b); 
   Energy2 cc = sqr(c); 
   Energy2 dd = sqr(d); 
   Energy2 ee = (b-c)*(a-d);
   
   Energy2 a1 = 0.5 * (aa+bb);
   Energy2 b1 = 0.5 * (cc+dd);
   InvEnergy4 c1 = 4./(sqr(a1-b1));
   
   Energy2 ff; 
   double ww; 
   Energy4 pp,qq,rr;
   // Choose mass of subsystem 23 with prescribed distribution
   const unsigned int MAXTRY = 100;
   unsigned int ntry=0;
   do {
     // ff is the mass squared of the 23 subsystem
     ff = UseRandom::rnd()*(cc-bb)+bb;
     
     // pp is ((m0+m1)^2 - m23^2)((m0-m1)^2-m23)
     pp = (aa-ff)*(bb-ff);
     
     // qq is ((m2+m3)^2 - m23^2)(|m2-m3|^2-m23^2)
     qq = (cc-ff)*(dd-ff);
     
     // weight
     ww = (fcn != NULL) ? (*fcn)(ff,a1,b1,c1) : 1.0;
     ww = sqr(ww);
     rr = ee*ff*UseRandom::rnd();
     ++ntry;
   } 
   while(pp*qq*ww < rr*rr && ntry < MAXTRY );
   if(ntry >= MAXTRY) {
     CurrentGenerator::log() << "Kinematics::threeBodyDecay can't generate momenta" 
 			    << " after " << MAXTRY << " attempts\n";
     return false;
   }
 
   // ff is the mass squared of subsystem 23
   // do 2 body decays 0->1+23, 23->2+3
   double CosAngle, AzmAngle;
   Lorentz5Momentum p23;
   
   p23.setMass(sqrt(ff));
   
   generateAngles(CosAngle,AzmAngle);
   bool status = twoBodyDecay(p0,p1.mass(),p23.mass(),CosAngle,AzmAngle,p1,p23);
   
   generateAngles(CosAngle,AzmAngle);
   status &= twoBodyDecay(p23,p2.mass(),p3.mass(),CosAngle,AzmAngle,p2,p3);
   return status;
 }
diff --git a/Utilities/Kinematics.h b/Utilities/Kinematics.h
--- a/Utilities/Kinematics.h
+++ b/Utilities/Kinematics.h
@@ -1,112 +1,120 @@
 // -*- C++ -*-
 //
 // Kinematics.h is a part of Herwig - A multi-purpose Monte Carlo event generator
 // Copyright (C) 2002-2019 The Herwig Collaboration
 //
 // Herwig is licenced under version 3 of the GPL, see COPYING for details.
 // Please respect the MCnet academic guidelines, see GUIDELINES for details.
 //
 //
 #ifndef HERWIG_Kinematics_H
 #define HERWIG_Kinematics_H
 
 // This is the declaration of the Kinematics class.
 
 #include <ThePEG/Config/ThePEG.h>
 #include "ThePEG/Vectors/ThreeVector.h"
 #include "ThePEG/Vectors/LorentzRotation.h"
 #include "ThePEG/Repository/UseRandom.h"
 #include <ThePEG/Vectors/Lorentz5Vector.h>
 
 namespace Herwig {
 
   using namespace ThePEG;
 
   /** \ingroup Utilities
    *  This is a namespace which provides some useful methods
    *  for kinematics computation, as the two body decays.
    * 
    *  NB) For other useful kinematical methods (and probably even those
    *      implemented in Kinematics class!):
    *          @see UtilityBase
    */
   namespace Kinematics {
 
     /**
+     *  Covariant boost for 2 not neccessarily collinear Vectors
+	 *  */
+    bool twoBodyBoost(Lorentz5Momentum & p1, 
+			Lorentz5Momentum & p2,
+			const Energy & Pcom,
+			const Axis & Dir);
+
+    /**
      *  Calculate the momenta for a two body decay
      * The return value indicates success or failure.
      * @param p The momentum of the decaying particle
      * @param m1 The mass of the first decay product
      * @param m2 The mass of the second decay product
      * @param unitDir1 Direction for the products in the rest frame of
      * the decaying particle
      * @param p1 The momentum of the first decay product
      * @param p2 The momentum of the second decay product
      */
     bool twoBodyDecay(const Lorentz5Momentum & p, 
 			     const Energy m1, const Energy m2,
 			     const Axis & unitDir1,
 			     Lorentz5Momentum & p1, Lorentz5Momentum & p2);
     
     /**
      * It returns the unit 3-vector with the given  cosTheta  and  phi.
      */
     inline Axis unitDirection(const double cosTheta, const double phi) {
       return ( fabs( cosTheta ) <= 1.0  ? 
          Axis( cos(phi)*sqrt(1.0-cosTheta*cosTheta) , 
          sin(phi)*sqrt(1.0-cosTheta*cosTheta) , cosTheta) : Axis() );
     }
 
     /**
      *  Calculate the momenta for a two body decay
      * The return value indicates success or failure.
      * @param p The momentum of the decaying particle
      * @param m1 The mass of the first decay product
      * @param m2 The mass of the second decay product
      * @param cosThetaStar1 Polar angle in rest frame 
      * @param phiStar1 Azimuthal angle in rest frame
      * @param p1 The momentum of the first decay product
      * @param p2 The momentum of the second decay product
      */
     inline bool twoBodyDecay(const Lorentz5Momentum & p, 
 			     const Energy m1, const Energy m2,
 			     const double cosThetaStar1, 
 			     const double phiStar1,
 			     Lorentz5Momentum & p1, Lorentz5Momentum & p2) {
       return twoBodyDecay(p,m1,m2,unitDirection(cosThetaStar1,phiStar1),p1,p2); 
     }
 
     /**
      * As the name implies, this takes the momentum p0 and does a flat three
      * body decay into p1..p3. The argument fcn is used to add additional
      * weights. If it is not used, the default is just flat in phasespace.
      * The return value indicates success or failure.
      */
     bool threeBodyDecay(Lorentz5Momentum p0, Lorentz5Momentum &p1, 
 			       Lorentz5Momentum &p2, Lorentz5Momentum &p3,
 			       double (*fcn)(Energy2,Energy2,Energy2,InvEnergy4) = NULL);
 
     /**
      * For the two body decay  M -> m1 + m2  it gives the module of the 
      * 3-momentum of the decay product in the rest frame of M.
      */
     inline Energy pstarTwoBodyDecay(const Energy M, 
 				    const Energy m1, const Energy m2) {
       return ( M > ZERO &&  m1 >=ZERO && m2 >= ZERO  && M > m1+m2 ?  
 	       Energy(sqrt(( sqr(M) - sqr(m1+m2) )*( sqr(M) - sqr(m1-m2) )) 
 		      / (2.0*M) ) : ZERO); 
     }
     
     /**
      * This just generates angles. First flat -1..1, second flat 0..2Pi
      */
     inline void generateAngles(double & ct, double & az) {
       ct = UseRandom::rnd()*2.0 - 1.0;  // Flat from -1..1
       az = UseRandom::rnd()*Constants::twopi;   
     }
   }
 
 }
 
 #endif /* HERWIG_Kinematics_H */