diff --git a/Hadronization/ClusterFinder.cc b/Hadronization/ClusterFinder.cc
--- a/Hadronization/ClusterFinder.cc
+++ b/Hadronization/ClusterFinder.cc
@@ -1,490 +1,490 @@
// -*- C++ -*-
//
// ClusterFinder.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 ClusterFinder class.
//
#include "ClusterFinder.h"
#include <ThePEG/Interface/ClassDocumentation.h>
#include <ThePEG/Interface/Switch.h>
#include <ThePEG/Persistency/PersistentOStream.h>
#include <ThePEG/Persistency/PersistentIStream.h>
#include <ThePEG/PDT/StandardMatchers.h>
#include <ThePEG/PDT/EnumParticles.h>
#include <ThePEG/Repository/EventGenerator.h>
#include <ThePEG/EventRecord/Collision.h>
#include "Herwig/Utilities/EnumParticles.h"
#include "Herwig/Utilities/Kinematics.h"
#include "Cluster.h"
#include <ThePEG/Utilities/DescribeClass.h>
#include "ThePEG/Interface/Reference.h"
using namespace Herwig;
DescribeClass<ClusterFinder,Interfaced>
describeClusterFinder("Herwig::ClusterFinder","Herwig.so");
IBPtr ClusterFinder::clone() const {
return new_ptr(*this);
}
IBPtr ClusterFinder::fullclone() const {
return new_ptr(*this);
}
void ClusterFinder::persistentOutput(PersistentOStream & os) const {
os << heavyDiquarks_ << diQuarkSelection_ << diQuarkOnShell_ << _hadronSpectrum;
}
void ClusterFinder::persistentInput(PersistentIStream & is, int) {
is >> heavyDiquarks_ >> diQuarkSelection_ >> diQuarkOnShell_ >> _hadronSpectrum;
}
void ClusterFinder::Init() {
static ClassDocumentation<ClusterFinder> documentation
("This class is responsible of finding clusters.");
static Reference<ClusterFinder,HadronSpectrum> interfaceHadronSpectrum
("HadronSpectrum",
"Set the hadron spectrum for this parton splitter.",
&ClusterFinder::_hadronSpectrum, false, false, false, false, false);
static Switch<ClusterFinder,unsigned int> interfaceHeavyDiquarks
("HeavyDiquarks",
"How to treat heavy quarks in baryon number violating clusters",
&ClusterFinder::heavyDiquarks_, 2, false, false);
static SwitchOption interfaceHeavyDiquarksDefault
(interfaceHeavyDiquarks,
"Allow",
"No special treatment, allow both heavy and doubly heavy diquarks",
0);
static SwitchOption interfaceHeavyDiquarksNoDoublyHeavy
(interfaceHeavyDiquarks,
"NoDoublyHeavy",
"Avoid having diquarks with twoo heavy quarks",
1);
static SwitchOption interfaceHeavyDiquarksNoHeavy
(interfaceHeavyDiquarks,
"NoHeavy",
"Try and avoid diquarks contain c and b altogether",
2);
static Switch<ClusterFinder,unsigned int> interfaceDiQuarkSelection
("DiQuarkSelection",
"Option controlling the selection of quarks to merge into a diquark in baryon-number violating clusters",
&ClusterFinder::diQuarkSelection_, 1, false, false);
static SwitchOption interfaceDiQuarkSelectionRandom
(interfaceDiQuarkSelection,
"Random",
"Randomly pick a pair to combine",
0);
static SwitchOption interfaceDiQuarkSelectionLowestMass
(interfaceDiQuarkSelection,
"LowestMass",
"Combine the lowest mass pair",
1);
static Switch<ClusterFinder,bool> interfaceDiQuarkOnShell
("DiQuarkOnShell",
"Force the diquark produced in baryon-number violating clusters to be on-shell",
&ClusterFinder::diQuarkOnShell_, false, false, false);
static SwitchOption interfaceDiQuarkOnShellYes
(interfaceDiQuarkOnShell,
"Yes",
"Force to be on-shell",
true);
static SwitchOption interfaceDiQuarkOnShellNo
(interfaceDiQuarkOnShell,
"No",
"Leave off-shell",
false);
}
ClusterVector ClusterFinder::formClusters(const PVector & partons) {
set<tPPtr> examinedSet; // colour particles already included in a cluster
map<tColinePtr, pair<tPPtr,tPPtr> > quarkQuark; // quark quark
map<tColinePtr, pair<tPPtr,tPPtr> > aQuarkQuark; // anti quark anti quark
ParticleSet inputParticles(partons.begin(),partons.end());
ClusterVector clusters;
// Loop over all current particles.
for(PVector::const_iterator pit=partons.begin();pit!=partons.end();++pit){
// Skip to the next particle if it is not coloured or already examined.
assert(*pit);
assert((*pit)->dataPtr());
if(!(**pit).data().coloured()
|| examinedSet.find(*pit) != examinedSet.end()) {
continue;
}
// We assume that a cluster is made of, at most, 3 constituents although
// in most cases the number will be 2; however, for baryon violating decays
// (for example in Susy model without R parity conservation) we can have 3
// constituents. In the latter case, a quark (antiquark) do not have an
// anticolour (colour) partner as usual, but its colour line either stems
// from a colour source, or ends in a colour sink. In the case of double
// baryon violating decays, but with overall baryon conservation
// ( for instance:
// tilde_u_R -> dbar_1 + dbar_2
// tilde_u_R_star -> d1 + d2
// where tilde_u_R and tilde_u_R_star are colour connected )
// a special treatment is needed, because first we have to process all
// partons in the current step, and then for each left pair of quarks which
// stem from a colour source we have to find the corresponding pair of
// anti-quarks which ends in a colour sink and is connected with the
// above colour source. These special pairs are kept into the maps:
// spec/CluHadConfig.hialQuarkQuarkMap and specialAntiQuarkAntiQuarkMap.
tParticleVector connected(3);
int iElement = 0;
connected[iElement++] = *pit;
bool specialCase = false;
if((*pit)->hasColour()) {
tPPtr partner =
(*pit)->colourLine()->getColouredParticle(partons.begin(),
partons.end(),
true);
if(partner) {
connected[iElement++]= partner;
}
// colour source : baryon-violating process
else {
if((*pit)->colourLine()->sourceNeighbours() != tColinePair()) {
tColinePair sourcePair = (*pit)->colourLine()->sourceNeighbours();
tColinePtr intCL = tColinePtr();
for(int i = 0; i < 2; ++i) {
tColinePtr pLine = i==0 ? sourcePair.first : sourcePair.second;
int saveNumElements = iElement;
for(tPVector::const_iterator cit = pLine->coloured().begin();
cit != pLine->coloured().end(); ++cit ) {
ParticleSet::const_iterator cjt = inputParticles.find(*cit);
if(cjt!=inputParticles.end()) connected[iElement++]= (*cit);
}
if(iElement == saveNumElements) intCL = pLine;
}
if(intCL && iElement == 2) {
specialCase = true;
pair<tPPtr,tPPtr> qp=pair<tPPtr,tPPtr>(connected[0],connected[1]);
quarkQuark.insert(pair<tColinePtr,pair<tPPtr,tPPtr> >(intCL,qp));
}
else if(iElement != 3) {
throw Exception() << "Colour connections fail in the hadronization for "
<< **pit << "in ClusterFinder::formClusters"
<< " for a coloured particle."
<< " Failed to find particles from a source"
<< Exception::runerror;
}
}
else {
throw Exception() << "Colour connections fail in the hadronization for "
<< **pit << "in ClusterFinder::formClusters for"
<< " a coloured particle"
<< Exception::runerror;
}
}
}
if((*pit)->hasAntiColour()) {
tPPtr partner =
(*pit)->antiColourLine()->getColouredParticle(partons.begin(),
partons.end(),
false);
if(partner) {
connected[iElement++]=partner;
}
// colour sink : baryon-violating process
else {
if((*pit)->antiColourLine()->sinkNeighbours() != tColinePair()) {
tColinePair sinkPair = (*pit)->antiColourLine()->sinkNeighbours();
tColinePtr intCL = tColinePtr();
for(int i = 0; i < 2; ++i) {
tColinePtr pLine = i==0 ? sinkPair.first : sinkPair.second;
int saveNumElements = iElement;
for(tPVector::const_iterator cit = pLine->antiColoured().begin();
cit != pLine->antiColoured().end(); ++cit ) {
ParticleSet::const_iterator cjt = inputParticles.find(*cit);
if(cjt!=inputParticles.end()) connected[iElement++]= (*cit);
}
if(iElement == saveNumElements) intCL = pLine;
}
if(intCL && iElement == 2) {
specialCase = true;
pair<tPPtr,tPPtr> aqp=pair<tPPtr,tPPtr>(connected[0],connected[1]);
aQuarkQuark.insert(pair<tColinePtr,pair<tPPtr,tPPtr> >(intCL,aqp));
}
else if( iElement !=3) {
throw Exception() << "Colour connections fail in the hadronization for "
<< **pit << "in ClusterFinder::formClusters for"
<< " an anti-coloured particle."
<< " Failed to find particles from a sink"
<< Exception::runerror;
}
}
else {
throw Exception() << "Colour connections fail in the hadronization for "
<< **pit << "in ClusterFinder::formClusters for"
<< " an anti-coloured particle"
<< Exception::runerror;
}
}
}
if(!specialCase) {
// Tag the components of the found cluster as already examined.
for (int i=0; i<iElement; ++i) examinedSet.insert(connected[i]);
// Create the cluster object with the colour connected particles
ClusterPtr cluPtr = new_ptr(Cluster(connected[0],connected[1],
connected[2]));
// add to the step
connected[0]->addChild(cluPtr);
connected[1]->addChild(cluPtr);
if(connected[2]) connected[2]->addChild(cluPtr);
clusters.push_back(cluPtr);
// Check if any of the components is a beam remnant, and if this
// is the case then inform the cluster.
// this will only work for baryon collisions
for (int i=0; i<iElement; ++i) {
bool fromRemnant = false;
tPPtr parent=connected[i];
while(parent) {
if(parent->id()==ParticleID::Remnant) {
fromRemnant = true;
break;
}
parent = parent->parents().empty() ? tPPtr() : parent->parents()[0];
}
if(fromRemnant&&DiquarkMatcher::Check(connected[i]->id()))
cluPtr->isBeamCluster(connected[i]);
}
}
}
// Treat now the special cases, if any. The idea is to find for each pair
// of quarks coming from a common colour source the corresponding pair of
// antiquarks coming from a common colour sink, connected to the above
// colour source via the same colour line. Then, randomly couple one of
// the two quarks with one of the two antiquarks, and do the same with the
// quark and antiquark left.
for(map<tColinePtr, pair<tPPtr,tPPtr> >::const_iterator
cit = quarkQuark.begin(); cit != quarkQuark.end(); ++cit ) {
tColinePtr coline = cit->first;
pair<tPPtr,tPPtr> quarkPair = cit->second;
if(aQuarkQuark.find( coline ) != aQuarkQuark.end()) {
pair<tPPtr,tPPtr> antiQuarkPair = aQuarkQuark.find(coline)->second;
ClusterPtr cluPtr1, cluPtr2;
if ( UseRandom::rndbool() ) {
cluPtr1 = new_ptr(Cluster(quarkPair.first , antiQuarkPair.first));
cluPtr2 = new_ptr(Cluster(quarkPair.second , antiQuarkPair.second));
quarkPair.first->addChild(cluPtr1);
antiQuarkPair.first->addChild(cluPtr1);
quarkPair.second->addChild(cluPtr2);
antiQuarkPair.second->addChild(cluPtr2);
} else {
cluPtr1 = new_ptr(Cluster(quarkPair.first , antiQuarkPair.second));
cluPtr2 = new_ptr(Cluster(quarkPair.second , antiQuarkPair.first));
quarkPair.second->addChild(cluPtr2);
antiQuarkPair.first->addChild(cluPtr2);
quarkPair.first->addChild(cluPtr1);
antiQuarkPair.second->addChild(cluPtr1);
}
clusters.push_back(cluPtr1);
clusters.push_back(cluPtr2);
}
else {
throw Exception() << "ClusterFinder::formClusters : "
<< "***Skip event: unable to match pairs in "
<< "Baryon-violating processes***"
<< Exception::eventerror;
}
}
return clusters;
}
namespace {
bool PartOrdering(tPPtr p1,tPPtr p2) {
return abs(p1->id())<abs(p2->id());
}
}
void ClusterFinder::reduceToTwoComponents(ClusterVector & clusters) {
// In order to preserve all of the information, we do not modify the
// directly the 3-component clusters, but instead we define new clusters,
// which are related to the original ones by a child-parent relationship,
// by considering two randomly chosen components as a diquark (or anti-diquark).
// These new clusters are first added to the vector vecNewRedefinedCluPtr,
// and at the end, when all input clusters have been examined, the elements of
// this vector will be copied in collecCluPtr (the reason is that it is not
// allowed to modify a STL container while iterating over it).
vector<tClusterPtr> redefinedClusters;
for(ClusterVector::iterator cluIter = clusters.begin() ;
cluIter != clusters.end() ; ++cluIter) {
tParticleVector vec;
if ( (*cluIter)->numComponents() != 3 ||
! (*cluIter)->isAvailable() ) continue;
tPPtr other;
for(unsigned int i = 0; i<(*cluIter)->numComponents(); i++) {
tPPtr part = (*cluIter)->particle(i);
if(!DiquarkMatcher::Check(*(part->dataPtr())))
vec.push_back(part);
else
other = part;
}
if(vec.size()<2) {
throw Exception() << "Could not make a diquark for a baryonic cluster decay from "
<< (*cluIter)->particle(0)->PDGName() << " "
<< (*cluIter)->particle(1)->PDGName() << " "
<< (*cluIter)->particle(2)->PDGName() << " "
<< " in ClusterFinder::reduceToTwoComponents()."
<< Exception::eventerror;
}
// order the vector so heaviest at the end
std::sort(vec.begin(),vec.end(),PartOrdering);
// Special treatment of heavy quarks
// avoid doubly heavy diquarks
if(heavyDiquarks_>=1 && vec.size()>2 &&
abs(vec[1]->id())>3 && abs(vec[0]->id())<=3) {
if(UseRandom::rndbool()) swap(vec[1],vec[2]);
other = vec[2];
vec.pop_back();
}
// avoid singly heavy diquarks
if(heavyDiquarks_==2 && vec.size()>2 &&
abs(vec[2]->id())>3 && abs(vec[1]->id())<=3) {
other = vec[2];
vec.pop_back();
}
// if there's a choice pick the pair to make a diquark from
if(vec.size()>2) {
unsigned int ichoice(0);
// random choice
if(diQuarkSelection_==0) {
ichoice = UseRandom::rnd3(1.0, 1.0, 1.0);
}
// pick the lightest quark pair
else if(diQuarkSelection_==1) {
Energy m12 = (vec[0]->momentum()+vec[1]->momentum()).m();
Energy m13 = (vec[0]->momentum()+vec[2]->momentum()).m();
Energy m23 = (vec[1]->momentum()+vec[2]->momentum()).m();
if (m13<=m12&&m13<=m23) ichoice = 2;
else if(m23<=m12&&m23<=m13) ichoice = 1;
}
else
assert(false);
// make the swaps so select pair first
switch (ichoice) {
case 0:
break;
case 1:
swap(vec[2],vec[0]);
break;
case 2:
swap(vec[2],vec[1]);
break;
}
}
// set up
tcPDPtr temp1 = vec[0]->dataPtr();
tcPDPtr temp2 = vec[1]->dataPtr();
if(!other) other = vec[2];
tcPDPtr dataDiquark = _hadronSpectrum->makeDiquark(temp1,temp2);
if(!dataDiquark)
- throw Exception() << "Could not make a diquark from"
+ throw Exception() << "Could not make a diquark from "
<< temp1->PDGName() << " and "
<< temp2->PDGName()
<< " in ClusterFinder::reduceToTwoComponents()"
<< Exception::eventerror;
// Create the new cluster (with two components) and assign to it the same
// momentum and position of the original (with three components) one.
// Furthermore, assign to the diquark component a momentum given by the
// sum of the two original components from which has been formed; for the
// position, we are assuming, very simply, that the diquark position is
// the average positions of the two original components.
// Notice that the mass (5-th component of the 5-momentum) of the diquark
// is set by hand to the constituent mass of the diquark (which is equal
// to the sum of the constituent masses of the two quarks which form the
// diquark) because the sum of 5-component vectors do add only the "normal"
// 4-components, not the 5-th one. After that, the 5-momentum of the diquark
// is in an inconsistent state, because the mass (5-th component) is not
// equal to the invariant mass obtained from the 4-momemtum. This is not
// unique to this kind of component (all perturbative components are in
// a similar situation), but it is not harmful.
// construct the diquark
PPtr diquark = dataDiquark->produceParticle();
vec[0]->addChild(diquark);
vec[1]->addChild(diquark);
diquark->set5Momentum(Lorentz5Momentum(vec[0]->momentum() + vec[1]->momentum(),
dataDiquark->constituentMass()));
// use the same method as for cluster to determine the diquark position
diquark->setVertex(Cluster::calculateX(vec[0],vec[1]));
// put on-shell if required
if(diQuarkOnShell_) {
Lorentz5Momentum psum = diquark->momentum()+other->momentum();
psum.rescaleMass();
Boost boost = psum.boostVector();
Lorentz5Momentum pother = other->momentum();
Lorentz5Momentum pdiquark = diquark->momentum();
pother.boost(-boost);
pdiquark.boost(-boost);
Energy pcm = Kinematics::pstarTwoBodyDecay(psum.mass(),
other->dataPtr()->constituentMass(),
diquark->dataPtr()->constituentMass());
if(pcm>ZERO) {
double fact = pcm/pother.vect().mag();
pother *= fact;
pdiquark *= fact;
pother .setMass(other->dataPtr()->constituentMass());
pdiquark.setMass(dataDiquark ->constituentMass());
pother .rescaleEnergy();
pdiquark.rescaleEnergy();
pother .boost(boost);
pdiquark.boost(boost);
other->set5Momentum(pother);
diquark->set5Momentum(pdiquark);
}
}
// make the new cluster
ClusterPtr nclus = new_ptr(Cluster(other,diquark));
//vec[0]->addChild(nclus);
//diquark->addChild(nclus);
// Set the parent/children relationship between the original cluster
// (the one with three components) with the new one (the one with two components)
// and add the latter to the vector of new redefined clusters.
(*cluIter)->addChild(nclus);
redefinedClusters.push_back(nclus);
}
// Add to collecCluPtr all of the redefined new clusters (indeed the
// pointers to them are added) contained in vecNewRedefinedCluPtr.
/// \todo why do we keep the original of the redefined clusters?
for (tClusterVector::const_iterator it = redefinedClusters.begin();
it != redefinedClusters.end(); ++it) {
clusters.push_back(*it);
}
}
diff --git a/Hadronization/ClusterFissioner.cc b/Hadronization/ClusterFissioner.cc
--- a/Hadronization/ClusterFissioner.cc
+++ b/Hadronization/ClusterFissioner.cc
@@ -1,1436 +1,1436 @@
// -*- 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"
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),
_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))
{}
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
<< _hadronSpectrum
<< _probPowFactor << _probShift << ounit(_kinThresholdShift,sqr(GeV));
}
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)
+ >> iunit(_btClM,GeV)
+ >> _iopRem >> iunit(_kappa, GeV/meter)
>> _enhanceSProb >> iunit(_m0Fission,GeV) >> _massMeasure
>> _hadronSpectrum
>> _probPowFactor >> _probShift >> iunit(_kinThresholdShift,sqr(GeV));
}
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);
}
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 (!( Q1diq || Q2diq )
&& (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 {
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 (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 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;
// 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);
tPDPtr diq;
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 (Mc < spectrum()->massLightestBaryonPair(pD1,pD2)) 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() ) {
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() ) {
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;
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();
}
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;
}
// 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
Lorentz5Momentum uRelCluster(p0Q1);
uRelCluster.boost( -pClu.boostVector() ); // boost from LAB to C
// sample direction (options = Default(aligned), Isotropic
// or FluxTube(gaussian pT kick))
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;
}
// relative momentum in centre of mass of cluster 1
Lorentz5Momentum uRelCluster1COM(p0Q1);
uRelCluster1COM.boost( -pClu1.boostVector() ); // boost from LAB to C1
// sample direction (options = Default(aligned), Isotropic
// or FluxTube(gaussian pT kick))
Axis DirClu1 = sampleDirection(uRelCluster1COM,
pClu1.mass(), pQ1.mass(), pQbar.mass());
Kinematics::twoBodyDecay(pClu1, pQ1.mass(), pQbar.mass(),
DirClu1, 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;
}
// relative momentum in centre of mass of cluster 2
Lorentz5Momentum uRelCluster2COM(p0Q1);
uRelCluster2COM.boost( -pClu2.boostVector() ); // boost from LAB to C2
// sample direction (options = Default(aligned), Isotropic
// or FluxTube(gaussian pT kick))
Axis DirClu2 = sampleDirection(uRelCluster2COM,
pClu2.mass(), pQ2bar.mass(), pQ.mass());
Kinematics::twoBodyDecay(pClu2, pQ.mass(), pQ2bar.mass(),
DirClu2, 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;
}