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diff --git a/Decay/General/GeneralTwoBodyDecayer.cc b/Decay/General/GeneralTwoBodyDecayer.cc
--- a/Decay/General/GeneralTwoBodyDecayer.cc
+++ b/Decay/General/GeneralTwoBodyDecayer.cc
@@ -1,731 +1,765 @@
// -*- C++ -*-
//
// GeneralTwoBodyDecayer.cc is a part of Herwig - A multi-purpose Monte Carlo event generator
// Copyright (C) 2002-2017 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 GeneralTwoBodyDecayer class.
//
#include "GeneralTwoBodyDecayer.h"
#include "ThePEG/Utilities/DescribeClass.h"
#include "ThePEG/Interface/ClassDocumentation.h"
#include "ThePEG/Persistency/PersistentOStream.h"
#include "ThePEG/Persistency/PersistentIStream.h"
#include "ThePEG/PDT/DecayMode.h"
#include "ThePEG/Utilities/Exception.h"
#include "Herwig/Shower/RealEmissionProcess.h"
using namespace Herwig;
ParticleVector GeneralTwoBodyDecayer::decay(const Particle & parent,
const tPDVector & children) const {
// return empty vector if products heavier than parent
Energy mout(ZERO);
for(tPDVector::const_iterator it=children.begin();
it!=children.end();++it) mout+=(**it).massMin();
if(mout>parent.mass()) return ParticleVector();
// generate the decay
bool cc;
int imode=modeNumber(cc,parent.dataPtr(),children);
// generate the kinematics
ParticleVector decay=generate(generateIntermediates(),cc,imode,parent);
// make the colour connections
colourConnections(parent, decay);
// return the answer
return decay;
}
void GeneralTwoBodyDecayer::doinit() {
PerturbativeDecayer::doinit();
assert( incoming_ && outgoing_.size()==2);
//create phase space mode
tPDVector extpart(3);
extpart[0] = incoming_;
extpart[1] = outgoing_[0];
extpart[2] = outgoing_[1];
addMode(new_ptr(DecayPhaseSpaceMode(extpart, this)), maxWeight_, vector<double>());
}
int GeneralTwoBodyDecayer::modeNumber(bool & cc, tcPDPtr parent,
const tPDVector & children) const {
long parentID = parent->id();
long id1 = children[0]->id();
long id2 = children[1]->id();
cc = false;
long out1 = outgoing_[0]->id();
long out2 = outgoing_[1]->id();
if( parentID == incoming_->id() &&
((id1 == out1 && id2 == out2) ||
(id1 == out2 && id2 == out1)) ) {
return 0;
}
else if(incoming_->CC() && parentID == incoming_->CC()->id()) {
cc = true;
if( outgoing_[0]->CC()) out1 = outgoing_[0]->CC()->id();
if( outgoing_[1]->CC()) out2 = outgoing_[1]->CC()->id();
if((id1 == out1 && id2 == out2) ||
(id1 == out2 && id2 == out1)) return 0;
}
return -1;
}
void GeneralTwoBodyDecayer::
colourConnections(const Particle & parent,
const ParticleVector & out) const {
PDT::Colour incColour(parent.data().iColour());
PDT::Colour outaColour(out[0]->data().iColour());
PDT::Colour outbColour(out[1]->data().iColour());
//incoming colour singlet
if(incColour == PDT::Colour0) {
// colour triplet-colourantitriplet
if((outaColour == PDT::Colour3 && outbColour == PDT::Colour3bar) ||
(outaColour == PDT::Colour3bar && outbColour == PDT::Colour3)) {
bool ac(out[0]->id() < 0);
out[0]->colourNeighbour(out[1],!ac);
}
//colour octet
else if(outaColour == PDT::Colour8 && outbColour == PDT::Colour8) {
out[0]->colourNeighbour(out[1]);
out[0]->antiColourNeighbour(out[1]);
}
// colour singlets
else if(outaColour == PDT::Colour0 && outbColour == PDT::Colour0) {
}
// unknown
else
throw Exception() << "Unknown outgoing colours for decaying "
<< "colour singlet in "
<< "GeneralTwoBodyDecayer::colourConnections "
<< outaColour << " " << outbColour
<< Exception::runerror;
}
//incoming colour triplet
else if(incColour == PDT::Colour3) {
// colour triplet + singlet
if(outaColour == PDT::Colour3 && outbColour == PDT::Colour0) {
out[0]->incomingColour(const_ptr_cast<tPPtr>(&parent));
}
//opposite order
else if(outaColour == PDT::Colour0 && outbColour == PDT::Colour3) {
out[1]->incomingColour(const_ptr_cast<tPPtr>(&parent));
}
// octet + triplet
else if(outaColour == PDT::Colour8 && outbColour == PDT::Colour3) {
out[0]->incomingColour(const_ptr_cast<tPPtr>(&parent));
out[1]->antiColourNeighbour(out[0]);
}
//opposite order
else if(outaColour == PDT::Colour3 && outbColour == PDT::Colour8) {
out[1]->incomingColour(const_ptr_cast<tPPtr>(&parent));
out[0]->antiColourNeighbour(out[1]);
}
else if(outaColour == PDT::Colour3bar && outaColour == PDT::Colour3bar) {
tColinePtr col[2] = {ColourLine::create(out[0],true),
ColourLine::create(out[1],true)};
parent.colourLine()->setSinkNeighbours(col[0],col[1]);
}
else
throw Exception() << "Unknown outgoing colours for decaying "
<< "colour triplet in "
<< "GeneralTwoBodyDecayer::colourConnections() "
<< outaColour << " " << outbColour
<< Exception::runerror;
}
// incoming colour anti triplet
else if(incColour == PDT::Colour3bar) {
// colour antitriplet +singlet
if(outaColour == PDT::Colour3bar && outbColour == PDT::Colour0) {
out[0]->incomingAntiColour(const_ptr_cast<tPPtr>(&parent));
}
//opposite order
else if(outaColour == PDT::Colour0 && outbColour == PDT::Colour3bar) {
out[1]->incomingAntiColour(const_ptr_cast<tPPtr>(&parent));
}
//octet + antitriplet
else if(outaColour == PDT::Colour3bar && outbColour == PDT::Colour8) {
out[1]->incomingAntiColour(const_ptr_cast<tPPtr>(&parent));
out[0]->colourNeighbour(out[1]);
}
//opposite order
else if(outaColour == PDT::Colour8 && outbColour == PDT::Colour3bar) {
out[0]->incomingAntiColour(const_ptr_cast<tPPtr>(&parent));
out[1]->colourNeighbour(out[0]);
}
else if(outaColour == PDT::Colour3 && outbColour == PDT::Colour3) {
tColinePtr col[2] = {ColourLine::create(out[0]),
ColourLine::create(out[1])};
parent.antiColourLine()->setSourceNeighbours(col[0],col[1]);
}
else
throw Exception() << "Unknown outgoing colours for decaying "
<< "colour antitriplet "
<< "in GeneralTwoBodyDecayer::colourConnections() "
<< outaColour << " " << outbColour
<< Exception::runerror;
}
//incoming colour octet
else if(incColour == PDT::Colour8) {
// triplet-antitriplet
if(outaColour == PDT::Colour3&&outbColour == PDT::Colour3bar) {
out[0]->incomingColour(const_ptr_cast<tPPtr>(&parent));
out[1]->incomingAntiColour(const_ptr_cast<tPPtr>(&parent));
}
// opposite order
else if(outbColour == PDT::Colour3&&outaColour == PDT::Colour3bar) {
out[0]->incomingAntiColour(const_ptr_cast<tPPtr>(&parent));
out[1]->incomingColour(const_ptr_cast<tPPtr>(&parent));
}
// neutral octet
else if(outaColour == PDT::Colour0&&outbColour == PDT::Colour8) {
out[1]->incomingColour(const_ptr_cast<tPPtr>(&parent));
out[1]->incomingAntiColour(const_ptr_cast<tPPtr>(&parent));
}
else if(outbColour == PDT::Colour0&&outaColour == PDT::Colour8) {
out[0]->incomingColour(const_ptr_cast<tPPtr>(&parent));
out[0]->incomingAntiColour(const_ptr_cast<tPPtr>(&parent));
}
else
throw Exception() << "Unknown outgoing colours for decaying "
<< "colour octet "
<< "in GeneralTwoBodyDecayer::colourConnections() "
<< outaColour << " " << outbColour
<< Exception::runerror;
}
else if(incColour == PDT::Colour6) {
if(outaColour == PDT::Colour3 && outbColour == PDT::Colour3) {
tPPtr tempParent = const_ptr_cast<tPPtr>(&parent);
Ptr<MultiColour>::pointer parentColour =
dynamic_ptr_cast<Ptr<MultiColour>::pointer>
(tempParent->colourInfo());
tColinePtr line1 = const_ptr_cast<tColinePtr>(parentColour->colourLines()[0]);
line1->addColoured(dynamic_ptr_cast<tPPtr>(out[0]));
tColinePtr line2 = const_ptr_cast<tColinePtr>(parentColour->colourLines()[1]);
line2->addColoured(dynamic_ptr_cast<tPPtr>(out[1]));
}
else
throw Exception() << "Unknown outgoing colours for decaying "
<< "colour sextet "
<< "in GeneralTwoBodyDecayer::colourConnections() "
<< outaColour << " " << outbColour
<< Exception::runerror;
}
else if(incColour == PDT::Colour6bar) {
if(outaColour == PDT::Colour3bar && outbColour == PDT::Colour3bar) {
tPPtr tempParent = const_ptr_cast<tPPtr>(&parent);
Ptr<MultiColour>::pointer parentColour =
dynamic_ptr_cast<Ptr<MultiColour>::pointer>
(tempParent->colourInfo());
tColinePtr line1 = const_ptr_cast<tColinePtr>(parentColour->antiColourLines()[0]);
line1->addAntiColoured(dynamic_ptr_cast<tPPtr>(out[0]));
tColinePtr line2 = const_ptr_cast<tColinePtr>(parentColour->antiColourLines()[1]);
line2->addAntiColoured(dynamic_ptr_cast<tPPtr>(out[1]));
}
else
throw Exception() << "Unknown outgoing colours for decaying "
<< "colour anti-sextet "
<< "in GeneralTwoBodyDecayer::colourConnections() "
<< outaColour << " " << outbColour
<< Exception::runerror;
}
else
throw Exception() << "Unknown incoming colour in "
<< "GeneralTwoBodyDecayer::colourConnections() "
<< incColour
<< Exception::runerror;
}
bool GeneralTwoBodyDecayer::twoBodyMEcode(const DecayMode & dm, int & mecode,
double & coupling) const {
assert(dm.parent()->id() == incoming_->id());
ParticleMSet::const_iterator pit = dm.products().begin();
long id1 = (*pit)->id();
++pit;
long id2 = (*pit)->id();
long id1t(outgoing_[0]->id()), id2t(outgoing_[1]->id());
mecode = -1;
coupling = 1.;
if( id1 == id1t && id2 == id2t ) {
return true;
}
else if( id1 == id2t && id2 == id1t ) {
return false;
}
else
assert(false);
return false;
}
void GeneralTwoBodyDecayer::persistentOutput(PersistentOStream & os) const {
os << incoming_ << outgoing_ << maxWeight_;
}
void GeneralTwoBodyDecayer::persistentInput(PersistentIStream & is, int) {
is >> incoming_ >> outgoing_ >> maxWeight_;
}
// The following static variable is needed for the type
// description system in ThePEG.
DescribeAbstractClass<GeneralTwoBodyDecayer,PerturbativeDecayer>
describeHerwigGeneralTwoBodyDecayer("Herwig::GeneralTwoBodyDecayer", "Herwig.so");
void GeneralTwoBodyDecayer::Init() {
static ClassDocumentation<GeneralTwoBodyDecayer> documentation
("This class is designed to be a base class for all 2 body decays"
"in a general model");
}
double GeneralTwoBodyDecayer::brat(const DecayMode &, const Particle & p,
double oldbrat) const {
ParticleVector children = p.children();
if( children.size() != 2 || !p.data().widthGenerator() )
return oldbrat;
// partial width for this mode
Energy scale = p.mass();
Energy pwidth =
partialWidth( make_pair(p.dataPtr(), scale),
make_pair(children[0]->dataPtr(), children[0]->mass()),
make_pair(children[1]->dataPtr(), children[1]->mass()) );
Energy width = p.data().widthGenerator()->width(p.data(), scale);
return pwidth/width;
}
void GeneralTwoBodyDecayer::doinitrun() {
PerturbativeDecayer::doinitrun();
for(unsigned int ix=0;ix<numberModes();++ix) {
double fact = pow(1.5,int(mode(ix)->externalParticles(0)->iSpin())-1);
mode(ix)->setMaxWeight(fact*mode(ix)->maxWeight());
}
}
double GeneralTwoBodyDecayer::colourFactor(tcPDPtr in, tcPDPtr out1,
tcPDPtr out2) const {
// identical particle symmetry factor
double output = out1->id()==out2->id() ? 0.5 : 1.;
// colour neutral incoming particle
if(in->iColour()==PDT::Colour0) {
// both colour neutral
if(out1->iColour()==PDT::Colour0 && out2->iColour()==PDT::Colour0)
output *= 1.;
// colour triplet/ antitriplet
else if((out1->iColour()==PDT::Colour3 && out2->iColour()==PDT::Colour3bar) ||
(out1->iColour()==PDT::Colour3bar && out2->iColour()==PDT::Colour3 ) ) {
output *= 3.;
}
// colour octet colour octet
else if(out1->iColour()==PDT::Colour8 && out2->iColour()==PDT::Colour8 ) {
output *= 8.;
}
else
throw Exception() << "Unknown colour for the outgoing particles"
<< " for decay colour neutral particle in "
<< "GeneralTwoBodyDecayer::colourFactor() for "
<< in->PDGName() << " -> "
<< out1->PDGName() << " " << out2->PDGName()
<< Exception::runerror;
}
// triplet
else if(in->iColour()==PDT::Colour3) {
// colour triplet + neutral
if((out1->iColour()==PDT::Colour0 && out2->iColour()==PDT::Colour3) ||
(out1->iColour()==PDT::Colour3 && out2->iColour()==PDT::Colour0) ) {
output *= 1.;
}
// colour triplet + octet
else if((out1->iColour()==PDT::Colour8 && out2->iColour()==PDT::Colour3) ||
(out1->iColour()==PDT::Colour3 && out2->iColour()==PDT::Colour8) ) {
output *= 4./3.;
}
// colour anti triplet anti triplet
else if(out1->iColour()==PDT::Colour3bar &&
out2->iColour()==PDT::Colour3bar) {
output *= 2.;
}
else
throw Exception() << "Unknown colour for the outgoing particles"
<< " for decay colour triplet particle in "
<< "GeneralTwoBodyDecayer::colourFactor() for "
<< in->PDGName() << " -> "
<< out1->PDGName() << " " << out2->PDGName()
<< Exception::runerror;
}
// anti triplet
else if(in->iColour()==PDT::Colour3bar) {
// colour anti triplet + neutral
if((out1->iColour()==PDT::Colour0 && out2->iColour()==PDT::Colour3bar ) ||
(out1->iColour()==PDT::Colour3bar && out2->iColour()==PDT::Colour0 ) ) {
output *= 1.;
}
// colour anti triplet + octet
else if((out1->iColour()==PDT::Colour8 && out2->iColour()==PDT::Colour3bar ) ||
(out1->iColour()==PDT::Colour3bar && out2->iColour()==PDT::Colour8 ) ) {
output *= 4./3.;
}
// colour triplet triplet
else if(out1->iColour()==PDT::Colour3 &&
out2->iColour()==PDT::Colour3) {
output *= 2.;
}
else
throw Exception() << "Unknown colour for the outgoing particles"
<< " for decay colour anti triplet particle in "
<< "GeneralTwoBodyDecayer::colourFactor() for "
<< in->PDGName() << " -> "
<< out1->PDGName() << " " << out2->PDGName()
<< Exception::runerror;
}
else if(in->iColour()==PDT::Colour8) {
// colour octet + neutral
if((out1->iColour()==PDT::Colour0 && out2->iColour()==PDT::Colour8 ) ||
(out1->iColour()==PDT::Colour8 && out2->iColour()==PDT::Colour0 ) ) {
output *= 1.;
}
// colour triplet/antitriplet
else if((out1->iColour()==PDT::Colour3 && out2->iColour()==PDT::Colour3bar) ||
(out1->iColour()==PDT::Colour3bar && out2->iColour()==PDT::Colour3 ) ) {
output *= 0.5;
}
else
throw Exception() << "Unknown colour for the outgoing particles"
<< " for decay colour octet particle in "
<< "GeneralTwoBodyDecayer::colourFactor() for "
<< in->PDGName() << " -> "
<< out1->PDGName() << " " << out2->PDGName()
<< Exception::runerror;
}
else if(in->iColour()==PDT::Colour6) {
// colour sextet -> triplet triplet
if( out1->iColour()==PDT::Colour3 && out2->iColour()==PDT::Colour3 ) {
output *= 1.;
}
else
throw Exception() << "Unknown colour for the outgoing particles"
<< " for decay colour sextet particle in "
<< "GeneralTwoBodyDecayer::colourFactor() for "
<< in->PDGName() << " -> "
<< out1->PDGName() << " " << out2->PDGName()
<< Exception::runerror;
}
else if(in->iColour()==PDT::Colour6bar) {
// colour sextet -> triplet triplet
if( out1->iColour()==PDT::Colour3bar && out2->iColour()==PDT::Colour3bar ) {
output *= 1.;
}
else
throw Exception() << "Unknown colour for the outgoing particles"
<< " for decay colour anti-sextet particle in "
<< "GeneralTwoBodyDecayer::colourFactor() for "
<< in->PDGName() << " -> "
<< out1->PDGName() << " " << out2->PDGName()
<< Exception::runerror;
}
else
throw Exception() << "Unknown colour "
<< in->iColour() << " for the decaying particle in "
<< "GeneralTwoBodyDecayer::colourFactor() for "
<< in->PDGName() << " -> "
<< out1->PDGName() << " " << out2->PDGName()
<< Exception::runerror;
return output;
}
Energy GeneralTwoBodyDecayer::partialWidth(PMPair inpart, PMPair outa,
PMPair outb) const {
// select the number of the mode
tPDVector children;
children.push_back(const_ptr_cast<PDPtr>(outa.first));
children.push_back(const_ptr_cast<PDPtr>(outb.first));
bool cc;
int nmode=modeNumber(cc,inpart.first,children);
tcPDPtr newchild[2] = {mode(nmode)->externalParticles(1),
mode(nmode)->externalParticles(2)};
// make the particles
Lorentz5Momentum pparent = Lorentz5Momentum(inpart.second);
PPtr parent = inpart.first->produceParticle(pparent);
Lorentz5Momentum pout[2];
double ctheta,phi;
Kinematics::generateAngles(ctheta,phi);
Kinematics::twoBodyDecay(pparent, outa.second, outb.second,
ctheta, phi,pout[0],pout[1]);
if( ( !cc && outa.first!=newchild[0]) ||
( cc && !(( outa.first->CC() && outa.first->CC() == newchild[0])||
( !outa.first->CC() && outa.first == newchild[0]) )))
swap(pout[0],pout[1]);
ParticleVector decay;
decay.push_back(newchild[0]->produceParticle(pout[0]));
decay.push_back(newchild[1]->produceParticle(pout[1]));
double me = me2(-1,*parent,decay,Initialize);
Energy pcm = Kinematics::pstarTwoBodyDecay(inpart.second,
outa.second, outb.second);
return me/(8.*Constants::pi)*pcm;
}
void GeneralTwoBodyDecayer::decayInfo(PDPtr incoming, PDPair outgoing) {
incoming_=incoming;
outgoing_.clear();
outgoing_.push_back(outgoing.first );
outgoing_.push_back(outgoing.second);
}
double GeneralTwoBodyDecayer::matrixElementRatio(const Particle & inpart,
const ParticleVector & decay2,
const ParticleVector & decay3,
MEOption meopt,
ShowerInteraction inter) {
// calculate R/B
double B = me2 (0, inpart, decay2, meopt);
double R = threeBodyME(0, inpart, decay3, inter, meopt);
return R/B;
}
const vector<DVector> & GeneralTwoBodyDecayer::getColourFactors(const Particle & inpart,
const ParticleVector & decay,
unsigned int & nflow) {
// calculate the colour factors for the three-body decay
- vector<int> sing,trip,atrip,oct;
+ vector<int> sing,trip,atrip,oct,sex,asex;
for(unsigned int it=0;it<decay.size();++it) {
if (decay[it]->dataPtr()->iColour() == PDT::Colour0 ) sing. push_back(it);
else if(decay[it]->dataPtr()->iColour() == PDT::Colour3 ) trip. push_back(it);
else if(decay[it]->dataPtr()->iColour() == PDT::Colour3bar ) atrip.push_back(it);
else if(decay[it]->dataPtr()->iColour() == PDT::Colour8 ) oct. push_back(it);
+ else if(decay[it]->dataPtr()->iColour() == PDT::Colour6 ) sex. push_back(it);
+ else if(decay[it]->dataPtr()->iColour() == PDT::Colour6bar ) asex. push_back(it);
}
// identical particle symmetry factor
double symFactor=1.;
if (( sing.size()==2 && decay[ sing[0]]->id()==decay[ sing[1]]->id()) ||
( trip.size()==2 && decay[ trip[0]]->id()==decay[ trip[1]]->id()) ||
(atrip.size()==2 && decay[atrip[0]]->id()==decay[atrip[1]]->id()) ||
( oct.size()==2 && decay[ oct[0]]->id()==decay[ oct[1]]->id()))
symFactor /= 2.;
else if (oct.size()==3 &&
decay[oct[0]]->id()==decay[oct[1]]->id() &&
decay[oct[0]]->id()==decay[oct[2]]->id())
symFactor /= 6.;
colour_ = vector<DVector>(1,DVector(1,symFactor*1.));
// decaying colour singlet
if(inpart.dataPtr()->iColour() == PDT::Colour0) {
if(trip.size()==1 && atrip.size()==1 && oct.size()==1) {
nflow = 1;
colour_ = vector<DVector>(1,DVector(1,symFactor*4.));
}
else if(trip.size()==1 && atrip.size()==1 && sing.size()==1) {
nflow = 1;
colour_ = vector<DVector>(1,DVector(1,symFactor*3.));
}
else if (oct.size()==3){
nflow = 1;
colour_ = vector<DVector>(1,DVector(1,symFactor*24.));
}
else if(sing.size()==3) {
nflow = 1;
colour_ = vector<DVector>(1,DVector(1,symFactor));
}
else
throw Exception() << "Unknown colour for the outgoing particles"
<< " for decay colour scalar particle in "
<< "GeneralTwoBodyDecayer::getColourFactors() for "
<< inpart. dataPtr()->PDGName() << " -> "
<< decay[0]->dataPtr()->PDGName() << " "
<< decay[1]->dataPtr()->PDGName() << " "
<< decay[2]->dataPtr()->PDGName()
<< Exception::runerror;
}
// decaying colour triplet
else if(inpart.dataPtr()->iColour() == PDT::Colour3) {
if(trip.size()==1 && sing.size()==1 && oct.size()==1) {
nflow = 1;
colour_ = vector<DVector>(1,DVector(1,symFactor*4./3.));
}
else if(trip.size()==1 && sing.size()==2) {
nflow = 1;
colour_ = vector<DVector>(1,DVector(1,symFactor));
}
else if(trip.size()==1 && oct.size()==2) {
nflow = 2;
colour_.clear();
colour_.resize(2,DVector(2,0.));
colour_[0][0] = symFactor*16./9.; colour_[0][1] = -symFactor*2./9.;
colour_[1][0] = -symFactor*2./9.; colour_[1][1] = symFactor*16./9.;
}
else if(atrip.size()==2 && sing.size()==1) {
nflow = 1;
colour_ = vector<DVector>(1,DVector(1,symFactor*2.));
}
else
throw Exception() << "Unknown colour for the outgoing particles"
<< " for decay colour triplet particle in "
<< "GeneralTwoBodyDecayer::getColourFactors() for "
<< inpart. dataPtr()->PDGName() << " -> "
<< decay[0]->dataPtr()->PDGName() << " "
<< decay[1]->dataPtr()->PDGName() << " "
<< decay[2]->dataPtr()->PDGName()
<< Exception::runerror;
}
// decaying colour anti-triplet
else if(inpart.dataPtr()->iColour() == PDT::Colour3bar) {
if(atrip.size()==1 && sing.size()==1 && oct.size()==1) {
nflow = 1;
colour_ = vector<DVector>(1,DVector(1,symFactor*4./3.));
}
else if(atrip.size()==1 && sing.size()==2) {
nflow = 1;
colour_ = vector<DVector>(1,DVector(1,symFactor));
}
else if(atrip.size()==1 && oct.size()==2){
nflow = 2;
colour_.clear();
colour_ .resize(2,DVector(2,0.));
colour_[0][0] = symFactor*16./9.; colour_[0][1] = -symFactor*2./9.;
colour_[1][0] = -symFactor*2./9.; colour_[1][1] = symFactor*16./9.;
}
else if(trip.size()==2 && sing.size()==1) {
nflow = 1;
colour_ = vector<DVector>(1,DVector(1,symFactor*2.));
}
else
throw Exception() << "Unknown colour for the outgoing particles"
<< " for decay colour anti-triplet particle in "
<< "GeneralTwoBodyDecayer::getColourFactors() for "
<< inpart. dataPtr()->PDGName() << " -> "
<< decay[0]->dataPtr()->PDGName() << " "
<< decay[1]->dataPtr()->PDGName() << " "
<< decay[2]->dataPtr()->PDGName()
<< Exception::runerror;
}
// decaying colour octet
else if(inpart.dataPtr()->iColour() == PDT::Colour8) {
if(oct.size()==1 && trip.size()==1 && atrip.size()==1) {
nflow = 2;
colour_.clear();
colour_.resize(2,DVector(2,0.));
colour_[0][0] = symFactor*2./3. ; colour_[0][1] = -symFactor*1./12.;
colour_[1][0] = -symFactor*1./12.; colour_[1][1] = symFactor*2./3. ;
}
else if (sing.size()==1 && trip.size()==1 && atrip.size()==1) {
nflow = 1;
colour_ = vector<DVector>(1,DVector(1,symFactor*0.5));
}
- else if (oct.size()==2 && sing.size()==1){
+ else if (oct.size()==2 && sing.size()==1) {
nflow = 1;
colour_ = vector<DVector>(1,DVector(1,symFactor*3.));
}
else
throw Exception() << "Unknown colour for the outgoing particles"
<< " for a decaying colour octet particle in "
<< "GeneralTwoBodyDecayer::getColourFactors() for "
<< inpart. dataPtr()->PDGName() << " -> "
<< decay[0]->dataPtr()->PDGName() << " "
<< decay[1]->dataPtr()->PDGName() << " "
<< decay[2]->dataPtr()->PDGName()
<< Exception::runerror;
}
+ // Sextet
+ else if(inpart.dataPtr()->iColour() == PDT::Colour6) {
+ if(trip.size()==2 && sing.size()==1) {
+ nflow = 1;
+ colour_ = vector<DVector>(1,DVector(1,symFactor));
+ }
+ else
+ throw Exception() << "Unknown colour for the outgoing particles"
+ << " for a decaying colour sextet particle in "
+ << "GeneralTwoBodyDecayer::getColourFactors() for "
+ << inpart. dataPtr()->PDGName() << " -> "
+ << decay[0]->dataPtr()->PDGName() << " "
+ << decay[1]->dataPtr()->PDGName() << " "
+ << decay[2]->dataPtr()->PDGName()
+ << Exception::runerror;
+ }
+ // anti Sextet
+ else if(inpart.dataPtr()->iColour() == PDT::Colour6bar) {
+ if(atrip.size()==2 && sing.size()==1) {
+ nflow = 1;
+ colour_ = vector<DVector>(1,DVector(1,symFactor));
+ }
+ else
+ throw Exception() << "Unknown colour for the outgoing particles"
+ << " for a decaying colour anti-sextet particle in "
+ << "GeneralTwoBodyDecayer::getColourFactors() for "
+ << inpart. dataPtr()->PDGName() << " -> "
+ << decay[0]->dataPtr()->PDGName() << " "
+ << decay[1]->dataPtr()->PDGName() << " "
+ << decay[2]->dataPtr()->PDGName()
+ << Exception::runerror;
+ }
else
throw Exception() << "Unknown colour for the decaying particle in "
<< "GeneralTwoBodyDecayer::getColourFactors() for "
<< inpart. dataPtr()->PDGName() << " -> "
<< decay[0]->dataPtr()->PDGName() << " "
<< decay[1]->dataPtr()->PDGName() << " "
<< decay[2]->dataPtr()->PDGName()
<< Exception::runerror;
return colour_;
}
const GeneralTwoBodyDecayer::CFlow &
GeneralTwoBodyDecayer::colourFlows(const Particle & inpart,
const ParticleVector & decay) {
// static initialization of commonly used colour structures
static const CFlow init = CFlow(3, CFlowPairVec(1, make_pair(0, 1.)));
static CFlow tripflow = init;
static CFlow atripflow = init;
static CFlow octflow = init;
static const CFlow fpflow = CFlow(4, CFlowPairVec(1, make_pair(0, 1.)));
static bool initialized = false;
if (! initialized) {
tripflow[2].resize(2, make_pair(0,1.));
tripflow[2][0] = make_pair(0, 1.);
tripflow[2][1] = make_pair(1,-1.);
tripflow[1][0] = make_pair(1, 1.);
atripflow[1].resize(2, make_pair(0,1.));
atripflow[1][0] = make_pair(0, 1.);
atripflow[1][1] = make_pair(1,-1.);
atripflow[2][0] = make_pair(1, 1.);
octflow[0].resize(2, make_pair(0,1.));
octflow[0][0] = make_pair(0,-1.);
octflow[0][1] = make_pair(1, 1.);
octflow[2][0] = make_pair(1, 1.);
initialized = true;
}
// main function body
int sing=0,trip=0,atrip=0,oct=0;
for (size_t it=0; it<decay.size(); ++it) {
switch ( decay[it]->dataPtr()->iColour() ) {
case PDT::Colour0: ++sing; break;
case PDT::Colour3: ++trip; break;
case PDT::Colour3bar: ++atrip; break;
case PDT::Colour8: ++oct; break;
/// @todo: handle these better
case PDT::ColourUndefined: break;
case PDT::Coloured: break;
case PDT::Colour6: break;
case PDT::Colour6bar: break;
}
}
const CFlow * retval = 0;
bool inconsistent4PV = true;
// decaying colour triplet
if(inpart.dataPtr()->iColour() == PDT::Colour3 &&
trip==1 && oct==2) {
retval = &tripflow;
}
// decaying colour anti-triplet
else if(inpart.dataPtr()->iColour() == PDT::Colour3bar &&
atrip==1 && oct==2){
retval = &atripflow;
}
// decaying colour octet
else if(inpart.dataPtr()->iColour() == PDT::Colour8 &&
oct==1 && trip==1 && atrip==1) {
retval = &octflow;
}
else {
inconsistent4PV = false;
retval = &fpflow;
}
return *retval;
}
double GeneralTwoBodyDecayer::threeBodyME(const int , const Particle &,
const ParticleVector &,
ShowerInteraction, MEOption) {
throw Exception() << "Base class PerturbativeDecayer::threeBodyME() "
<< "called, should have an implementation in the inheriting class"
<< Exception::runerror;
return 0.;
}
diff --git a/Decay/General/Makefile.am b/Decay/General/Makefile.am
--- a/Decay/General/Makefile.am
+++ b/Decay/General/Makefile.am
@@ -1,73 +1,74 @@
noinst_LTLIBRARIES = libHwGeneralDecay.la
libHwGeneralDecay_la_SOURCES = \
GeneralTwoBodyDecayer.h GeneralTwoBodyDecayer.fh GeneralTwoBodyDecayer.cc \
GeneralThreeBodyDecayer.h GeneralThreeBodyDecayer.fh \
GeneralThreeBodyDecayer.cc \
GeneralCurrentDecayer.h GeneralCurrentDecayer.fh GeneralCurrentDecayer.cc \
GeneralFourBodyDecayer.h GeneralFourBodyDecayer.fh \
GeneralFourBodyDecayer.cc \
StoFFFFDecayer.h StoFFFFDecayer.cc
+# check the gauge invariance of corrections (for testing ONLY)
#libHwGeneralDecay_la_CPPFLAGS= $(AM_CPPFLAGS) -DGAUGE_CHECK
nodist_libHwGeneralDecay_la_SOURCES = \
GeneralDecayer__all.cc
BUILT_SOURCES = GeneralDecayer__all.cc
CLEANFILES = GeneralDecayer__all.cc
GeneralDecayer__all.cc : $(DIR_H_FILES) $(DIR_CC_FILES) Makefile
@echo "Concatenating .cc files into $@"
@$(top_srcdir)/cat_with_cpplines $(DIR_CC_FILES) > $@
EXTRA_DIST = $(ALL_H_FILES) $(ALL_CC_FILES)
DIR_H_FILES = $(addprefix $(srcdir)/,$(ALL_H_FILES))
ALL_H_FILES = \
FFSDecayer.h \
FFVDecayer.h \
SFFDecayer.h \
SSSDecayer.h \
SSVDecayer.h \
SVVDecayer.h \
TFFDecayer.h \
TSSDecayer.h \
TVVDecayer.h \
VFFDecayer.h \
VSSDecayer.h \
VVSDecayer.h \
VVVDecayer.h \
SRFDecayer.h \
FRSDecayer.h \
FRVDecayer.h \
FtoFFFDecayer.h \
StoSFFDecayer.h \
StoFFVDecayer.h \
VtoFFVDecayer.h \
FtoFVVDecayer.h \
FFVCurrentDecayer.h
DIR_CC_FILES = $(addprefix $(srcdir)/,$(ALL_CC_FILES))
ALL_CC_FILES = \
FFSDecayer.cc \
FFVDecayer.cc \
SFFDecayer.cc \
SSSDecayer.cc \
SSVDecayer.cc \
SVVDecayer.cc \
TFFDecayer.cc \
TSSDecayer.cc \
TVVDecayer.cc \
VFFDecayer.cc \
VSSDecayer.cc \
VVSDecayer.cc \
VVVDecayer.cc \
SRFDecayer.cc \
FRSDecayer.cc \
FRVDecayer.cc \
FtoFFFDecayer.cc \
StoSFFDecayer.cc \
StoFFVDecayer.cc \
VtoFFVDecayer.cc \
FtoFVVDecayer.cc \
FFVCurrentDecayer.cc
diff --git a/Decay/PerturbativeDecayer.cc b/Decay/PerturbativeDecayer.cc
--- a/Decay/PerturbativeDecayer.cc
+++ b/Decay/PerturbativeDecayer.cc
@@ -1,1001 +1,1037 @@
// -*- C++ -*-
//
// This is the implementation of the non-inlined, non-templated member
// functions of the PerturbativeDecayer class.
//
#include "PerturbativeDecayer.h"
#include "ThePEG/Interface/ClassDocumentation.h"
#include "ThePEG/EventRecord/Particle.h"
#include "ThePEG/Repository/UseRandom.h"
#include "ThePEG/Repository/EventGenerator.h"
#include "ThePEG/Utilities/DescribeClass.h"
#include "ThePEG/Persistency/PersistentOStream.h"
#include "ThePEG/Persistency/PersistentIStream.h"
#include "ThePEG/Interface/Reference.h"
#include "ThePEG/Interface/Parameter.h"
#include "ThePEG/Interface/Switch.h"
#include "ThePEG/Utilities/EnumIO.h"
using namespace Herwig;
void PerturbativeDecayer::persistentOutput(PersistentOStream & os) const {
os << ounit(pTmin_,GeV) << oenum(inter_) << alphaS_ << alphaEM_ << useMEforT2_;
}
void PerturbativeDecayer::persistentInput(PersistentIStream & is, int) {
is >> iunit(pTmin_,GeV) >> ienum(inter_) >> alphaS_ >> alphaEM_ >> useMEforT2_;
}
// The following static variable is needed for the type
// description system in ThePEG.
DescribeAbstractClass<PerturbativeDecayer,DecayIntegrator>
describeHerwigPerturbativeDecayer("Herwig::PerturbativeDecayer",
"Herwig.so HwPerturbativeDecay.so");
void PerturbativeDecayer::Init() {
static ClassDocumentation<PerturbativeDecayer> documentation
("The PerturbativeDecayer class is the mase class for perturbative decays in Herwig");
static Parameter<PerturbativeDecayer,Energy> interfacepTmin
("pTmin",
"Minimum transverse momentum from gluon radiation",
&PerturbativeDecayer::pTmin_, GeV, 1.0*GeV, 0.0*GeV, 10.0*GeV,
false, false, Interface::limited);
static Switch<PerturbativeDecayer,ShowerInteraction> interfaceInteractions
("Interactions",
"which interactions to include for the hard corrections",
&PerturbativeDecayer::inter_, ShowerInteraction::QCD, false, false);
static SwitchOption interfaceInteractionsQCD
(interfaceInteractions,
"QCD",
"QCD Only",
ShowerInteraction::QCD);
static SwitchOption interfaceInteractionsQED
(interfaceInteractions,
"QED",
"QED only",
ShowerInteraction::QED);
static SwitchOption interfaceInteractionsQCDandQED
(interfaceInteractions,
"QCDandQED",
"Both QCD and QED",
ShowerInteraction::Both);
static Reference<PerturbativeDecayer,ShowerAlpha> interfaceAlphaS
("AlphaS",
"Object for the coupling in the generation of hard QCD radiation",
&PerturbativeDecayer::alphaS_, false, false, true, true, false);
static Reference<PerturbativeDecayer,ShowerAlpha> interfaceAlphaEM
("AlphaEM",
"Object for the coupling in the generation of hard QED radiation",
&PerturbativeDecayer::alphaEM_, false, false, true, true, false);
static Switch<PerturbativeDecayer,bool> interfaceUseMEForT2
("UseMEForT2",
"Use the matrix element correction, if available to fill the T2"
" region for the decay shower and don't fill using the shower",
&PerturbativeDecayer::useMEforT2_, true, false, false);
static SwitchOption interfaceUseMEForT2Shower
(interfaceUseMEForT2,
"Shower",
"Use the shower to fill the T2 region",
false);
static SwitchOption interfaceUseMEForT2ME
(interfaceUseMEForT2,
"ME",
"Use the Matrix element to fill the T2 region",
true);
}
double PerturbativeDecayer::matrixElementRatio(const Particle & ,
const ParticleVector & ,
const ParticleVector & ,
MEOption ,
ShowerInteraction ) {
throw Exception() << "Base class PerturbativeDecayer::matrixElementRatio() "
<< "called, should have an implementation in the inheriting class"
<< Exception::runerror;
return 0.;
}
RealEmissionProcessPtr PerturbativeDecayer::generateHardest(RealEmissionProcessPtr born) {
return getHardEvent(born,false,inter_);
}
RealEmissionProcessPtr PerturbativeDecayer::applyHardMatrixElementCorrection(RealEmissionProcessPtr born) {
return getHardEvent(born,true,ShowerInteraction::QCD);
}
RealEmissionProcessPtr PerturbativeDecayer::getHardEvent(RealEmissionProcessPtr born,
bool inDeadZone,
ShowerInteraction inter) {
// check one incoming
assert(born->bornIncoming().size()==1);
// check exactly two outgoing particles
assert(born->bornOutgoing().size()==2); // search for coloured particles
bool colouredParticles=born->bornIncoming()[0]->dataPtr()->coloured();
bool chargedParticles=born->bornIncoming()[0]->dataPtr()->charged();
for(unsigned int ix=0;ix<born->bornOutgoing().size();++ix) {
if(born->bornOutgoing()[ix]->dataPtr()->coloured())
colouredParticles=true;
if(born->bornOutgoing()[ix]->dataPtr()->charged())
chargedParticles=true;
}
// if no coloured/charged particles return
if ( !colouredParticles && !chargedParticles ) return RealEmissionProcessPtr();
if ( !colouredParticles && inter==ShowerInteraction::QCD ) return RealEmissionProcessPtr();
if ( ! chargedParticles && inter==ShowerInteraction::QED ) return RealEmissionProcessPtr();
// for decay b -> a c
// set progenitors
PPtr cProgenitor = born->bornOutgoing()[0];
PPtr aProgenitor = born->bornOutgoing()[1];
// get the decaying particle
PPtr bProgenitor = born->bornIncoming()[0];
// identify which dipoles are required
vector<DipoleType> dipoles;
if(!identifyDipoles(dipoles,aProgenitor,bProgenitor,cProgenitor,inter)) {
return RealEmissionProcessPtr();
}
Energy trialpT = pTmin_;
LorentzRotation eventFrame;
vector<Lorentz5Momentum> momenta;
vector<Lorentz5Momentum> trialMomenta(4);
PPtr finalEmitter, finalSpectator;
PPtr trialEmitter, trialSpectator;
DipoleType finalType(FFa,ShowerInteraction::QCD);
for (int i=0; i<int(dipoles.size()); ++i) {
// assign emitter and spectator based on current dipole
if (dipoles[i].type==FFc || dipoles[i].type==IFc || dipoles[i].type==IFbc){
trialEmitter = cProgenitor;
trialSpectator = aProgenitor;
}
else if (dipoles[i].type==FFa || dipoles[i].type==IFa || dipoles[i].type==IFba){
trialEmitter = aProgenitor;
trialSpectator = cProgenitor;
}
// find rotation from lab to frame with the spectator along -z
LorentzRotation trialEventFrame(bProgenitor->momentum().findBoostToCM());
Lorentz5Momentum pspectator = (trialEventFrame*trialSpectator->momentum());
trialEventFrame.rotateZ( -pspectator.phi() );
trialEventFrame.rotateY( -pspectator.theta() - Constants::pi );
// invert it
trialEventFrame.invert();
// try to generate an emission
pT_ = pTmin_;
vector<Lorentz5Momentum> trialMomenta
= hardMomenta(bProgenitor, trialEmitter, trialSpectator,
dipoles, i, inDeadZone);
// select dipole which gives highest pT emission
if(pT_>trialpT) {
trialpT = pT_;
momenta = trialMomenta;
eventFrame = trialEventFrame;
finalEmitter = trialEmitter;
finalSpectator = trialSpectator;
finalType = dipoles[i];
if (dipoles[i].type==FFc || dipoles[i].type==FFa ) {
if((momenta[3]+momenta[1]).m2()-momenta[1].m2()>
(momenta[3]+momenta[2]).m2()-momenta[2].m2()) {
swap(finalEmitter,finalSpectator);
swap(momenta[1],momenta[2]);
}
}
}
}
pT_ = trialpT;
// if no emission return
if(momenta.empty()) {
if(inter==ShowerInteraction::Both || inter==ShowerInteraction::QCD)
born->pT()[ShowerInteraction::QCD] = pTmin_;
if(inter==ShowerInteraction::Both || inter==ShowerInteraction::QED)
born->pT()[ShowerInteraction::QED] = pTmin_;
return born;
}
// rotate momenta back to the lab
for(unsigned int ix=0;ix<momenta.size();++ix) {
momenta[ix] *= eventFrame;
}
// set maximum pT for subsequent branchings
if(inter==ShowerInteraction::Both || inter==ShowerInteraction::QCD)
born->pT()[ShowerInteraction::QCD] = pT_;
if(inter==ShowerInteraction::Both || inter==ShowerInteraction::QED)
born->pT()[ShowerInteraction::QED] = pT_;
// get ParticleData objects
tcPDPtr b = bProgenitor ->dataPtr();
tcPDPtr e = finalEmitter ->dataPtr();
tcPDPtr s = finalSpectator->dataPtr();
tcPDPtr boson = getParticleData(finalType.interaction==ShowerInteraction::QCD ?
ParticleID::g : ParticleID::gamma);
// create new ShowerParticles
PPtr emitter = e ->produceParticle(momenta[1]);
PPtr spectator = s ->produceParticle(momenta[2]);
PPtr gauge = boson->produceParticle(momenta[3]);
PPtr incoming = b ->produceParticle(bProgenitor->momentum());
// insert the particles
born->incoming().push_back(incoming);
unsigned int iemit(0),ispect(0);
for(unsigned int ix=0;ix<born->bornOutgoing().size();++ix) {
if(born->bornOutgoing()[ix]==finalEmitter) {
born->outgoing().push_back(emitter);
iemit = born->outgoing().size();
}
else if(born->bornOutgoing()[ix]==finalSpectator) {
born->outgoing().push_back(spectator);
ispect = born->outgoing().size();
}
}
born->outgoing().push_back(gauge);
if(!spectator->dataPtr()->coloured() ||
(finalType.type != FFa && finalType.type!=FFc) ) ispect = 0;
born->emitter(iemit);
born->spectator(ispect);
born->emitted(3);
// boost if being use as ME correction
if(inDeadZone) {
if(finalType.type==IFa || finalType.type==IFba) {
LorentzRotation trans(cProgenitor->momentum().findBoostToCM());
trans.boost(spectator->momentum().boostVector());
born->transformation(trans);
}
else if(finalType.type==IFc || finalType.type==IFbc) {
LorentzRotation trans(bProgenitor->momentum().findBoostToCM());
trans.boost(spectator->momentum().boostVector());
born->transformation(trans);
}
}
// set the interaction
born->interaction(finalType.interaction);
// set up colour lines
getColourLines(born);
// return the tree
return born;
}
bool PerturbativeDecayer::identifyDipoles(vector<DipoleType> & dipoles,
PPtr & aProgenitor,
PPtr & bProgenitor,
PPtr & cProgenitor,
ShowerInteraction inter) const {
// identify any QCD dipoles
if(inter==ShowerInteraction::QCD ||
inter==ShowerInteraction::Both) {
PDT::Colour bColour = bProgenitor->dataPtr()->iColour();
PDT::Colour cColour = cProgenitor->dataPtr()->iColour();
PDT::Colour aColour = aProgenitor->dataPtr()->iColour();
// decaying colour singlet
if (bColour==PDT::Colour0 ) {
if ((cColour==PDT::Colour3 && aColour==PDT::Colour3bar) ||
(cColour==PDT::Colour3bar && aColour==PDT::Colour3) ||
(cColour==PDT::Colour8 && aColour==PDT::Colour8)){
dipoles.push_back(DipoleType(FFa,ShowerInteraction::QCD));
dipoles.push_back(DipoleType(FFc,ShowerInteraction::QCD));
}
}
// decaying colour triplet
else if (bColour==PDT::Colour3 ) {
if (cColour==PDT::Colour3 && aColour==PDT::Colour0){
dipoles.push_back(DipoleType(IFbc,ShowerInteraction::QCD));
dipoles.push_back(DipoleType(IFc ,ShowerInteraction::QCD));
}
else if (cColour==PDT::Colour0 && aColour==PDT::Colour3){
dipoles.push_back(DipoleType(IFba,ShowerInteraction::QCD));
dipoles.push_back(DipoleType(IFa ,ShowerInteraction::QCD));
}
else if (cColour==PDT::Colour8 && aColour==PDT::Colour3){
dipoles.push_back(DipoleType(IFbc,ShowerInteraction::QCD));
dipoles.push_back(DipoleType(IFc ,ShowerInteraction::QCD));
dipoles.push_back(DipoleType(FFc ,ShowerInteraction::QCD));
dipoles.push_back(DipoleType(FFa ,ShowerInteraction::QCD));
}
else if (cColour==PDT::Colour3 && aColour==PDT::Colour8){
dipoles.push_back(DipoleType(IFba,ShowerInteraction::QCD));
dipoles.push_back(DipoleType(IFa ,ShowerInteraction::QCD));
dipoles.push_back(DipoleType(FFc ,ShowerInteraction::QCD));
dipoles.push_back(DipoleType(FFa ,ShowerInteraction::QCD));
}
}
// decaying colour anti-triplet
else if (bColour==PDT::Colour3bar) {
if ((cColour==PDT::Colour3bar && aColour==PDT::Colour0)){
dipoles.push_back(DipoleType(IFbc,ShowerInteraction::QCD));
dipoles.push_back(DipoleType(IFc ,ShowerInteraction::QCD));
}
else if ((cColour==PDT::Colour0 && aColour==PDT::Colour3bar)){
dipoles.push_back(DipoleType(IFba,ShowerInteraction::QCD));
dipoles.push_back(DipoleType(IFa ,ShowerInteraction::QCD));
}
else if (cColour==PDT::Colour8 && aColour==PDT::Colour3bar){
dipoles.push_back(DipoleType(IFbc,ShowerInteraction::QCD));
dipoles.push_back(DipoleType(IFc ,ShowerInteraction::QCD));
dipoles.push_back(DipoleType(FFc ,ShowerInteraction::QCD));
dipoles.push_back(DipoleType(FFa ,ShowerInteraction::QCD));
}
else if (cColour==PDT::Colour3bar && aColour==PDT::Colour8){
dipoles.push_back(DipoleType(IFba,ShowerInteraction::QCD));
dipoles.push_back(DipoleType(IFa ,ShowerInteraction::QCD));
dipoles.push_back(DipoleType(FFc ,ShowerInteraction::QCD));
dipoles.push_back(DipoleType(FFa ,ShowerInteraction::QCD));
}
}
// decaying colour octet
else if (bColour==PDT::Colour8){
if ((cColour==PDT::Colour3 && aColour==PDT::Colour3bar) ||
(cColour==PDT::Colour3bar && aColour==PDT::Colour3)){
dipoles.push_back(DipoleType(IFba,ShowerInteraction::QCD));
dipoles.push_back(DipoleType(IFbc,ShowerInteraction::QCD));
dipoles.push_back(DipoleType(IFa,ShowerInteraction::QCD));
dipoles.push_back(DipoleType(IFc,ShowerInteraction::QCD));
}
else if (cColour==PDT::Colour8 && aColour==PDT::Colour0){
dipoles.push_back(DipoleType(IFbc,ShowerInteraction::QCD));
dipoles.push_back(DipoleType(IFc,ShowerInteraction::QCD));
}
else if (cColour==PDT::Colour0 && aColour==PDT::Colour8){
dipoles.push_back(DipoleType(IFba,ShowerInteraction::QCD));
dipoles.push_back(DipoleType(IFa,ShowerInteraction::QCD));
}
}
}
// QED dipoles
if(inter==ShowerInteraction::Both ||
inter==ShowerInteraction::QED) {
const bool & bCharged = bProgenitor->dataPtr()->charged();
const bool & cCharged = cProgenitor->dataPtr()->charged();
const bool & aCharged = aProgenitor->dataPtr()->charged();
// initial-final
if(bCharged && aCharged) {
dipoles.push_back(DipoleType(IFba,ShowerInteraction::QED));
dipoles.push_back(DipoleType(IFa ,ShowerInteraction::QED));
}
if(bCharged && cCharged) {
dipoles.push_back(DipoleType(IFbc,ShowerInteraction::QED));
dipoles.push_back(DipoleType(IFc ,ShowerInteraction::QED));
}
// final-state
if(aCharged && cCharged) {
dipoles.push_back(DipoleType(FFa,ShowerInteraction::QED));
dipoles.push_back(DipoleType(FFc,ShowerInteraction::QED));
}
}
// check colour structure is allowed
return !dipoles.empty();
}
vector<Lorentz5Momentum> PerturbativeDecayer::hardMomenta(PPtr in, PPtr emitter,
PPtr spectator,
const vector<DipoleType> &dipoles,
int i, bool inDeadZone) {
double C = 6.3;
double ymax = 10.;
double ymin = -ymax;
// get masses of the particles
mb_ = in ->momentum().mass();
e_ = emitter ->momentum().mass()/mb_;
s_ = spectator->momentum().mass()/mb_;
e2_ = sqr(e_);
s2_ = sqr(s_);
vector<Lorentz5Momentum> particleMomenta (4);
Energy2 lambda = sqr(mb_)*sqrt(1.+sqr(s2_)+sqr(e2_)-2.*s2_-2.*e2_-2.*s2_*e2_);
// calculate A
double A = (ymax-ymin)*C/Constants::twopi;
if(dipoles[i].interaction==ShowerInteraction::QCD)
A *= alphaS() ->overestimateValue();
else
A *= alphaEM()->overestimateValue();
Energy pTmax = mb_*(sqr(1.-s_)-e2_)/(2.*(1.-s_));
// if no possible branching return
if ( pTmax < pTmin_ ) {
particleMomenta.clear();
return particleMomenta;
}
while (pTmax >= pTmin_) {
// generate pT, y and phi values
Energy pT = pTmax*pow(UseRandom::rnd(),(1./A));
if (pT < pTmin_) {
particleMomenta.clear();
break;
}
double phi = UseRandom::rnd()*Constants::twopi;
double y = ymin+UseRandom::rnd()*(ymax-ymin);
double weight[2] = {0.,0.};
double xs[2], xe[2], xe_z[2], xg;
for (unsigned int j=0; j<2; j++) {
// check if the momenta are physical
if (!calcMomenta(j, pT, y, phi, xg, xs[j], xe[j], xe_z[j], particleMomenta))
continue;
// check if point lies within phase space
if (!psCheck(xg, xs[j]))
continue;
// check if point lies within the dead-zone (if required)
if(inDeadZone) {
if(!inTotalDeadZone(xg,xs[j],dipoles,i)) continue;
}
// decay products for 3 body decay
PPtr inpart = in ->dataPtr()->produceParticle(particleMomenta[0]);
ParticleVector decay3;
decay3.push_back(emitter ->dataPtr()->produceParticle(particleMomenta[1]));
decay3.push_back(spectator->dataPtr()->produceParticle(particleMomenta[2]));
if(dipoles[i].interaction==ShowerInteraction::QCD)
decay3.push_back(getParticleData(ParticleID::g )->produceParticle(particleMomenta[3]));
else
decay3.push_back(getParticleData(ParticleID::gamma)->produceParticle(particleMomenta[3]));
// decay products for 2 body decay
Lorentz5Momentum p1(ZERO,ZERO, lambda/2./mb_,(mb_/2.)*(1.+e2_-s2_),mb_*e_);
Lorentz5Momentum p2(ZERO,ZERO,-lambda/2./mb_,(mb_/2.)*(1.+s2_-e2_),mb_*s_);
ParticleVector decay2;
decay2.push_back(emitter ->dataPtr()->produceParticle(p1));
decay2.push_back(spectator->dataPtr()->produceParticle(p2));
if (dipoles[i].type==FFa || dipoles[i].type==IFa || dipoles[i].type==IFba) {
swap(decay2[0],decay2[1]);
swap(decay3[0],decay3[1]);
}
// calculate matrix element ratio R/B
double meRatio = matrixElementRatio(*inpart,decay2,decay3,Initialize,dipoles[i].interaction);
// calculate dipole factor
InvEnergy2 dipoleSum = ZERO;
InvEnergy2 numerator = ZERO;
for (int k=0; k<int(dipoles.size()); ++k) {
// skip dipoles which are not of the interaction being considered
if(dipoles[k].interaction!=dipoles[i].interaction) continue;
InvEnergy2 dipole = abs(calculateDipole(dipoles[k],*inpart,decay3));
dipoleSum += dipole;
if (k==i) numerator = dipole;
}
meRatio *= numerator/dipoleSum;
// calculate jacobian
Energy2 denom = (mb_-particleMomenta[3].e())*particleMomenta[2].vect().mag() -
particleMomenta[2].e()*particleMomenta[3].z();
InvEnergy2 J = (particleMomenta[2].vect().mag2())/(lambda*denom);
// calculate weight
weight[j] = meRatio*fabs(sqr(pT)*J)/C/Constants::twopi;
if(dipoles[i].interaction==ShowerInteraction::QCD)
weight[j] *= alphaS() ->ratio(pT*pT);
else
weight[j] *= alphaEM()->ratio(pT*pT);
}
// accept point if weight > R
if (weight[0] + weight[1] > UseRandom::rnd()) {
if (weight[0] > (weight[0] + weight[1])*UseRandom::rnd()) {
particleMomenta[1].setE( (mb_/2.)*xe [0]);
particleMomenta[1].setZ( (mb_/2.)*xe_z[0]);
particleMomenta[2].setE( (mb_/2.)*xs [0]);
particleMomenta[2].setZ(-(mb_/2.)*sqrt(sqr(xs[0])-4.*s2_));
}
else {
particleMomenta[1].setE( (mb_/2.)*xe [1]);
particleMomenta[1].setZ( (mb_/2.)*xe_z[1]);
particleMomenta[2].setE( (mb_/2.)*xs [1]);
particleMomenta[2].setZ(-(mb_/2.)*sqrt(sqr(xs[1])-4.*s2_));
}
pT_ = pT;
break;
}
// if there's no branching lower the pT
pTmax = pT;
}
return particleMomenta;
}
bool PerturbativeDecayer::calcMomenta(int j, Energy pT, double y, double phi,
double& xg, double& xs, double& xe, double& xe_z,
vector<Lorentz5Momentum>& particleMomenta){
// calculate xg
xg = 2.*pT*cosh(y) / mb_;
if (xg>(1. - sqr(e_ + s_)) || xg<0.) return false;
// calculate the two values of xs
double xT = 2.*pT / mb_;
double A = 4.-4.*xg+sqr(xT);
double B = 4.*(3.*xg-2.+2.*e2_-2.*s2_-sqr(xg)-xg*e2_+xg*s2_);
double L = 1.+sqr(s2_)+sqr(e2_)-2.*s2_-2.*e2_-2.*s2_*e2_;
double det = 16.*( -L*sqr(xT)+pow(xT,4)*s2_+2.*xg*sqr(xT)*(1.-s2_-e2_)+
L*sqr(xg)-sqr(xg*xT)*(1.+s2_)+pow(xg,4)+
2.*pow(xg,3)*(-1.+s2_+e2_) );
if (det<0.) return false;
if (j==0) xs = (-B+sqrt(det))/(2.*A);
if (j==1) xs = (-B-sqrt(det))/(2.*A);
// check value of xs is physical
if (xs>(1.+s2_-e2_) || xs<2.*s_) return false;
// calculate xe
xe = 2.-xs-xg;
// check value of xe is physical
if (xe>(1.+e2_-s2_) || xe<2.*e_) return false;
// calculate xe_z
double root1 = sqrt(max(0.,sqr(xs)-4.*s2_)), root2 = sqrt(max(0.,sqr(xe)-4.*e2_-sqr(xT)));
double epsilon_p = -root1+xT*sinh(y)+root2;
double epsilon_m = -root1+xT*sinh(y)-root2;
// find direction of emitter
if (fabs(epsilon_p) < 1.e-10) xe_z = sqrt(sqr(xe)-4.*e2_-sqr(xT));
else if (fabs(epsilon_m) < 1.e-10) xe_z = -sqrt(sqr(xe)-4.*e2_-sqr(xT));
else return false;
// check the emitter is on shell
if (fabs((sqr(xe)-sqr(xT)-sqr(xe_z)-4.*e2_))>1.e-10) return false;
// calculate 4 momenta
particleMomenta[0].setE ( mb_);
particleMomenta[0].setX ( ZERO);
particleMomenta[0].setY ( ZERO);
particleMomenta[0].setZ ( ZERO);
particleMomenta[0].setMass( mb_);
particleMomenta[1].setE ( mb_*xe/2.);
particleMomenta[1].setX (-pT*cos(phi));
particleMomenta[1].setY (-pT*sin(phi));
particleMomenta[1].setZ ( mb_*xe_z/2.);
particleMomenta[1].setMass( mb_*e_);
particleMomenta[2].setE ( mb_*xs/2.);
particleMomenta[2].setX ( ZERO);
particleMomenta[2].setY ( ZERO);
particleMomenta[2].setZ (-mb_*sqrt(sqr(xs)-4.*s2_)/2.);
particleMomenta[2].setMass( mb_*s_);
particleMomenta[3].setE ( pT*cosh(y));
particleMomenta[3].setX ( pT*cos(phi));
particleMomenta[3].setY ( pT*sin(phi));
particleMomenta[3].setZ ( pT*sinh(y));
particleMomenta[3].setMass( ZERO);
return true;
}
bool PerturbativeDecayer::psCheck(const double xg, const double xs) {
// check is point is in allowed region of phase space
double xe_star = (1.-s2_+e2_-xg)/sqrt(1.-xg);
double xg_star = xg/sqrt(1.-xg);
if ((sqr(xe_star)-4.*e2_) < 1e-10) return false;
double xs_max = (4.+4.*s2_-sqr(xe_star+xg_star)+
sqr(sqrt(sqr(xe_star)-4.*e2_)+xg_star))/ 4.;
double xs_min = (4.+4.*s2_-sqr(xe_star+xg_star)+
sqr(sqrt(sqr(xe_star)-4.*e2_)-xg_star))/ 4.;
if (xs < xs_min || xs > xs_max) return false;
return true;
}
InvEnergy2 PerturbativeDecayer::calculateDipole(const DipoleType & dipoleId,
const Particle & inpart,
const ParticleVector & decay3) {
// calculate dipole for decay b->ac
InvEnergy2 dipole = ZERO;
double x1 = 2.*decay3[0]->momentum().e()/mb_;
double x2 = 2.*decay3[1]->momentum().e()/mb_;
double xg = 2.*decay3[2]->momentum().e()/mb_;
double mu12 = sqr(decay3[0]->mass()/mb_);
double mu22 = sqr(decay3[1]->mass()/mb_);
tcPDPtr part[3] = {inpart.dataPtr(),decay3[0]->dataPtr(),decay3[1]->dataPtr()};
if(dipoleId.type==FFa || dipoleId.type == IFa || dipoleId.type == IFba) {
swap(part[1],part[2]);
swap(x1,x2);
swap(mu12,mu22);
}
// radiation from b with initial-final connection
if (dipoleId.type==IFba || dipoleId.type==IFbc) {
dipole = -2./sqr(mb_*xg);
dipole *= colourCoeff(part[0],part[1],part[2],dipoleId);
}
// radiation from a/c with initial-final connection
else if (dipoleId.type==IFa || dipoleId.type==IFc) {
double z = 1. - xg/(1.-mu22+mu12);
dipole = (-2.*mu12/sqr(1.-x2+mu22-mu12)/sqr(mb_) + (1./(1.-x2+mu22-mu12)/sqr(mb_))*
(2./(1.-z)-dipoleSpinFactor(part[1],z)));
dipole *= colourCoeff(part[1],part[0],part[2],dipoleId);
}
// radiation from a/c with final-final connection
else if (dipoleId.type==FFa || dipoleId.type==FFc) {
double z = 1. + ((x1-1.+mu22-mu12)/(x2-2.*mu22));
double y = (1.-x2-mu12+mu22)/(1.-mu12-mu22);
double vt = sqrt((1.-sqr(e_+s_))*(1.-sqr(e_-s_)))/(1.-mu12-mu22);
double v = sqrt(sqr(2.*mu22+(1.-mu12-mu22)*(1.-y))-4.*mu22)
/(1.-y)/(1.-mu12-mu22);
if(part[1]->iSpin()!=PDT::Spin1) {
dipole = (1./(1.-x2+mu22-mu12)/sqr(mb_))*
((2./(1.-z*(1.-y)))-vt/v*(dipoleSpinFactor(part[1],z)+(2.*mu12/(1.+mu22-mu12-x2))));
}
else {
dipole = (1./(1.-x2+mu22-mu12)/sqr(mb_))*
(1./(1.-z*(1.-y))+1./(1.-(1.-z)*(1.-y))+(z*(1.-z)-2.)/v-vt/v*(2.*mu12/(1.+mu22-mu12-x2)));
}
dipole *= colourCoeff(part[1],part[2],part[0],dipoleId);
}
// coupling prefactors
dipole *= 8.*Constants::pi;
if(dipoleId.interaction==ShowerInteraction::QCD)
dipole *= alphaS() ->value(mb_*mb_);
else
dipole *= alphaEM()->value(mb_*mb_);
// return the answer
return dipole;
}
double PerturbativeDecayer::dipoleSpinFactor(tcPDPtr part, double z){
// calculate the spin dependent component of the dipole
if (part->iSpin()==PDT::Spin0)
return 2.;
else if (part->iSpin()==PDT::Spin1Half)
return (1. + z);
else if (part->iSpin()==PDT::Spin1)
return -(z*(1.-z) - 1./(1.-z) + 1./z -2.);
return 0.;
}
double PerturbativeDecayer::colourCoeff(tcPDPtr emitter,
tcPDPtr spectator,
tcPDPtr other,
DipoleType dipole) {
if(dipole.interaction==ShowerInteraction::QCD) {
// calculate the colour factor of the dipole
double numerator=1.;
double denominator=1.;
if (emitter->iColour()!=PDT::Colour0 &&
spectator->iColour()!=PDT::Colour0 &&
other->iColour()!=PDT::Colour0) {
if (emitter->iColour() ==PDT::Colour3 ||
emitter->iColour() ==PDT::Colour3bar) numerator=-4./3;
else if (emitter->iColour() ==PDT::Colour8) numerator=-3. ;
denominator=-1.*numerator;
if (spectator->iColour()==PDT::Colour3 ||
spectator->iColour()==PDT::Colour3bar) numerator-=4./3;
else if (spectator->iColour()==PDT::Colour8) numerator-=3. ;
if (other->iColour() ==PDT::Colour3 ||
other->iColour() ==PDT::Colour3bar) numerator+=4./3;
else if (other->iColour() ==PDT::Colour8) numerator+=3. ;
numerator*=(-1./2.);
}
if (emitter->iColour()==PDT::Colour3 ||
emitter->iColour()== PDT::Colour3bar) numerator*=4./3.;
else if (emitter->iColour()==PDT::Colour8 &&
spectator->iColour()!=PDT::Colour8) numerator*=3.;
else if (emitter->iColour()==PDT::Colour8 &&
spectator->iColour()==PDT::Colour8) numerator*=6.;
return (numerator/denominator);
}
else {
double val = double(emitter->iCharge()*spectator->iCharge())/9.;
// FF dipoles
if(dipole.type==FFa || dipole.type == FFc) {
return val;
}
else {
return -val;
}
}
}
void PerturbativeDecayer::getColourLines(RealEmissionProcessPtr real) {
// extract the particles
- vector<PPtr> branchingPart;
+ vector<tPPtr> branchingPart;
branchingPart.push_back(real->incoming()[0]);
for(unsigned int ix=0;ix<real->outgoing().size();++ix) {
branchingPart.push_back(real->outgoing()[ix]);
}
- vector<unsigned int> sing,trip,atrip,oct;
+ vector<unsigned int> sing,trip,atrip,oct,sex,asex;
for (size_t ib=0;ib<branchingPart.size()-1;++ib) {
if (branchingPart[ib]->dataPtr()->iColour()==PDT::Colour0 ) sing. push_back(ib);
else if(branchingPart[ib]->dataPtr()->iColour()==PDT::Colour3 ) trip. push_back(ib);
else if(branchingPart[ib]->dataPtr()->iColour()==PDT::Colour3bar) atrip.push_back(ib);
else if(branchingPart[ib]->dataPtr()->iColour()==PDT::Colour8 ) oct. push_back(ib);
+ else if(branchingPart[ib]->dataPtr()->iColour()==PDT::Colour6 ) sex. push_back(ib);
+ else if(branchingPart[ib]->dataPtr()->iColour()==PDT::Colour6bar) asex. push_back(ib);
}
// decaying colour singlet
if (branchingPart[0]->dataPtr()->iColour()==PDT::Colour0) {
// 0 -> 3 3bar
if (trip.size()==1 && atrip.size()==1) {
if(real->interaction()==ShowerInteraction::QCD) {
branchingPart[atrip[0]]->colourConnect(branchingPart[ 3 ]);
branchingPart[ 3 ]->colourConnect(branchingPart[trip[0]]);
}
else {
branchingPart[atrip[0]]->colourConnect(branchingPart[trip[0]]);
}
}
// 0 -> 8 8
else if (oct.size()==2 ) {
if(real->interaction()==ShowerInteraction::QCD) {
bool col = UseRandom::rndbool();
branchingPart[oct[0]]->colourConnect(branchingPart[ 3 ],col);
branchingPart[ 3 ]->colourConnect(branchingPart[oct[1]],col);
branchingPart[oct[1]]->colourConnect(branchingPart[oct[0]],col);
}
else {
branchingPart[oct[0]]->colourConnect(branchingPart[oct[1]]);
branchingPart[oct[1]]->colourConnect(branchingPart[oct[0]]);
}
}
else
assert(real->interaction()==ShowerInteraction::QED);
}
// decaying colour triplet
else if (branchingPart[0]->dataPtr()->iColour()==PDT::Colour3 ){
// 3 -> 3 0
if (trip.size()==2 && sing.size()==1) {
if(real->interaction()==ShowerInteraction::QCD) {
branchingPart[3]->incomingColour(branchingPart[trip[0]]);
branchingPart[3]-> colourConnect(branchingPart[trip[1]]);
}
else {
branchingPart[trip[1]]->incomingColour(branchingPart[trip[0]]);
}
}
// 3 -> 3 8
else if (trip.size()==2 && oct.size()==1) {
if(real->interaction()==ShowerInteraction::QCD) {
// 8 emit incoming partner
if(real->emitter()==oct[0]&&real->spectator()==0) {
branchingPart[ 3 ]->incomingColour(branchingPart[trip[0]]);
branchingPart[ 3 ]-> colourConnect(branchingPart[oct[0] ]);
branchingPart[oct[0]]-> colourConnect(branchingPart[trip[1]]);
}
// 8 emit final spectator or vice veras
else {
branchingPart[oct[0]]->incomingColour(branchingPart[trip[0]]);
branchingPart[oct[0]]-> colourConnect(branchingPart[ 3 ]);
branchingPart[ 3 ]-> colourConnect(branchingPart[trip[1]]);
}
}
else {
branchingPart[oct[0]]->incomingColour(branchingPart[trip[0]]);
branchingPart[oct[0]]-> colourConnect(branchingPart[trip[1]]);
}
}
// 3 -> 3bar 3bar
else if(trip.size() ==1 && atrip.size()==2) {
if(real->interaction()==ShowerInteraction::QCD)
assert(false);
else {
tColinePtr col[3] = {ColourLine::create(branchingPart[ trip[0]],false),
ColourLine::create(branchingPart[atrip[0]],true ),
ColourLine::create(branchingPart[atrip[1]],true)};
col[0]->setSinkNeighbours(col[1],col[2]);
}
}
else
assert(false);
}
// decaying colour anti-triplet
else if (branchingPart[0]->dataPtr()->iColour()==PDT::Colour3bar) {
// 3bar -> 3bar 0
if (atrip.size()==2 && sing.size()==1) {
if(real->interaction()==ShowerInteraction::QCD) {
branchingPart[3]->incomingColour(branchingPart[atrip[0]],true);
branchingPart[3]-> colourConnect(branchingPart[atrip[1]],true);
}
else {
branchingPart[atrip[1]]->incomingColour(branchingPart[atrip[0]],true);
}
}
// 3 -> 3 8
else if (atrip.size()==2 && oct.size()==1){
if(real->interaction()==ShowerInteraction::QCD) {
// 8 emit incoming partner
if(real->emitter()==oct[0]&&real->spectator()==0) {
branchingPart[ 3 ]->incomingColour(branchingPart[atrip[0]],true);
branchingPart[ 3 ]-> colourConnect(branchingPart[oct[0] ],true);
branchingPart[oct[0]]-> colourConnect(branchingPart[atrip[1]],true);
}
// 8 emit final spectator or vice veras
else {
if(real->interaction()==ShowerInteraction::QCD) {
branchingPart[oct[0]]->incomingColour(branchingPart[atrip[0]],true);
branchingPart[oct[0]]-> colourConnect(branchingPart[ 3 ],true);
branchingPart[3]-> colourConnect(branchingPart[atrip[1]] ,true);
}
}
}
else {
branchingPart[oct[0]]->incomingColour(branchingPart[atrip[0]],true);
branchingPart[oct[0]]-> colourConnect(branchingPart[atrip[1]],true);
}
}
// 3bar -> bar bar
else if(atrip.size() ==1 && trip.size()==2) {
if(real->interaction()==ShowerInteraction::QCD)
assert(false);
else {
tColinePtr col[3] = {ColourLine::create(branchingPart[atrip[0]],true ),
ColourLine::create(branchingPart[ trip[0]],false),
ColourLine::create(branchingPart[ trip[1]],false)};
col[0]->setSourceNeighbours(col[1],col[2]);
}
}
else
assert(false);
}
// decaying colour octet
else if(branchingPart[0]->dataPtr()->iColour()==PDT::Colour8 ) {
// 8 -> 3 3bar
if (trip.size()==1 && atrip.size()==1) {
if(real->interaction()==ShowerInteraction::QCD) {
// 3 emits
if(trip[0]==real->emitter()) {
branchingPart[3] ->incomingColour(branchingPart[oct[0]] );
branchingPart[3] -> colourConnect(branchingPart[trip[0]]);
branchingPart[atrip[0]]->incomingColour(branchingPart[oct[0]],true);
}
// 3bar emits
else {
branchingPart[3] ->incomingColour(branchingPart[oct[0]] ,true);
branchingPart[3] -> colourConnect(branchingPart[atrip[0]],true);
branchingPart[trip[0]]->incomingColour(branchingPart[oct[0]] );
}
}
else {
branchingPart[trip[0]]->incomingColour(branchingPart[oct[0]] );
branchingPart[atrip[0]]->incomingColour(branchingPart[oct[0]],true);
}
}
// 8 -> 8 0
else if (sing.size()==1 && oct.size()==2) {
if(real->interaction()==ShowerInteraction::QCD) {
bool col = UseRandom::rndbool();
branchingPart[ 3 ]->colourConnect (branchingPart[oct[1]], col);
branchingPart[ 3 ]->incomingColour(branchingPart[oct[0]], col);
branchingPart[oct[1]]->incomingColour(branchingPart[oct[0]],!col);
}
else {
branchingPart[oct[1]]->incomingColour(branchingPart[oct[0]]);
branchingPart[oct[1]]->incomingColour(branchingPart[oct[0]],true);
}
}
else
assert(false);
}
+ // sextet
+ else if(branchingPart[0]->dataPtr()->iColour() == PDT::Colour6) {
+ if(trip.size()==2) {
+ assert(real->interaction()==ShowerInteraction::QED);
+ Ptr<MultiColour>::pointer parentColour =
+ dynamic_ptr_cast<Ptr<MultiColour>::pointer>
+ (branchingPart[0]->colourInfo());
+ for(unsigned int ix=0;ix<2;++ix) {
+ ColinePtr cline = new_ptr(ColourLine());
+ parentColour->colourLine(cline);
+ cline->addColoured(branchingPart[trip[ix]]);
+ }
+ }
+ else
+ assert(false);
+ }
+ // antisextet
+ else if(branchingPart[0]->dataPtr()->iColour() == PDT::Colour6bar) {
+ if(atrip.size()==2) {
+ assert(real->interaction()==ShowerInteraction::QED);
+ Ptr<MultiColour>::pointer parentColour =
+ dynamic_ptr_cast<Ptr<MultiColour>::pointer>
+ (branchingPart[0]->colourInfo());
+ for(unsigned int ix=0;ix<2;++ix) {
+ ColinePtr cline = new_ptr(ColourLine());
+ parentColour->antiColourLine(cline);
+ cline->addColoured(branchingPart[atrip[ix]],true);
+ }
+ }
+ else
+ assert(false);
+ }
+ else
+ assert(false);
}
PerturbativeDecayer::phaseSpaceRegion
PerturbativeDecayer::inInitialFinalDeadZone(double xg, double xa,
double a, double c) const {
double lam = sqrt(1.+a*a+c*c-2.*a-2.*c-2.*a*c);
double kappab = 1.+0.5*(1.-a+c+lam);
double kappac = kappab-1.+c;
double kappa(0.);
// check whether or not in the region for emission from c
double r = 0.5;
if(c!=0.) r += 0.5*c/(1.+a-xa);
double pa = sqrt(sqr(xa)-4.*a);
double z = ((2.-xa)*(1.-r)+r*pa-xg)/pa;
if(z<1. && z>0.) {
kappa = (1.+a-c-xa)/(z*(1.-z));
if(kappa<kappac)
return emissionFromC;
}
// check in region for emission from b (T1)
double cq = sqr(1.+a-c)-4*a;
double bq = -2.*kappab*(1.-a-c);
double aq = sqr(kappab)-4.*a*(kappab-1);
double dis = sqr(bq)-4.*aq*cq;
z=1.-(-bq-sqrt(dis))/2./aq;
double w = 1.-(1.-z)*(kappab-1.);
double xgmax = (1.-z)*kappab;
// possibly in T1 region
if(xg<xgmax) {
z = 1.-xg/kappab;
kappa=kappab;
}
// possibly in T2 region
else {
aq = 4.*a;
bq = -4.*a*(2.-xg);
cq = sqr(1.+a-c-xg);
dis = sqr(bq)-4.*aq*cq;
z = (-bq-sqrt(dis))/2./aq;
kappa = xg/(1.-z);
}
// compute limit on xa
double u = 1.+a-c-(1.-z)*kappa;
w = 1.-(1.-z)*(kappa-1.);
double v = sqr(u)-4.*z*a*w;
if(v<0. && v>-1e-10) v= 0.;
v = sqrt(v);
if(xa<0.5*((u+v)/w+(u-v)/z)) {
if(xg<xgmax)
return emissionFromA1;
else if(useMEforT2_)
return deadZone;
else
return emissionFromA2;
}
else
return deadZone;
}
PerturbativeDecayer::phaseSpaceRegion
PerturbativeDecayer::inFinalFinalDeadZone(double xb, double xc,
double b, double c) const {
// basic kinematics
double lam = sqrt(1.+b*b+c*c-2.*b-2.*c-2.*b*c);
// check whether or not in the region for emission from b
double r = 0.5;
if(b!=0.) r+=0.5*b/(1.+c-xc);
double pc = sqrt(sqr(xc)-4.*c);
double z = -((2.-xc)*r-r*pc-xb)/pc;
if(z<1. and z>0.) {
if((1.-b+c-xc)/(z*(1.-z))<0.5*(1.+b-c+lam)) return emissionFromB;
}
// check whether or not in the region for emission from c
r = 0.5;
if(c!=0.) r+=0.5*c/(1.+b-xb);
double pb = sqrt(sqr(xb)-4.*b);
z = -((2.-xb)*r-r*pb-xc)/pb;
if(z<1. and z>0.) {
if((1.-c+b-xb)/(z*(1.-z))<0.5*(1.-b+c+lam)) return emissionFromC;
}
return deadZone;
}
bool PerturbativeDecayer::inTotalDeadZone(double xg, double xs,
const vector<DipoleType> & dipoles,
int i) {
double xb,xc,b,c;
if(dipoles[i].type==FFa || dipoles[i].type == IFa || dipoles[i].type == IFba) {
xc = xs;
xb = 2.-xg-xs;
b = e2_;
c = s2_;
}
else {
xb = xs;
xc = 2.-xg-xs;
b = s2_;
c = e2_;
}
for(unsigned int ix=0;ix<dipoles.size();++ix) {
if(dipoles[ix].interaction!=dipoles[i].interaction)
continue;
// should also remove negative QED dipoles but shouldn't be an issue unless we
// support QED ME corrections
switch (dipoles[ix].type) {
case FFa :
if(inFinalFinalDeadZone(xb,xc,b,c)!=deadZone) return false;
break;
case FFc :
if(inFinalFinalDeadZone(xc,xb,c,b)!=deadZone) return false;
break;
case IFa : case IFba:
if(inInitialFinalDeadZone(xg,xc,c,b)!=deadZone) return false;
break;
case IFc : case IFbc:
if(inInitialFinalDeadZone(xg,xb,b,c)!=deadZone) return false;
break;
}
}
return true;
}

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