Page MenuHomeHEPForge
Files F19244179

FIMqgxDipole.cc
No OneTemporary
Actions

Size
5 KB
Referenced Files
None
Subscribers
None

FIMqgxDipole.cc
View Options

// -*- C++ -*-
//
// FIqgxDipole.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 FIMqgxDipole class.
//
#include "FIMqgxDipole.h"
#include "ThePEG/Interface/ClassDocumentation.h"
#include "ThePEG/Utilities/DescribeClass.h"
#include "ThePEG/MatrixElement/Tree2toNDiagram.h"
#include "ThePEG/StandardModel/StandardModelBase.h"
#include "ThePEG/Persistency/PersistentOStream.h"
#include "ThePEG/Persistency/PersistentIStream.h"
#include "Herwig/MatrixElement/Matchbox/Base/DipoleRepository.h"
//#include "Herwig/MatrixElement/Matchbox/Phasespace/FILightTildeKinematics.h"
//#include "Herwig/MatrixElement/Matchbox/Phasespace/FILightInvertedTildeKinematics.h"
#include "Herwig/MatrixElement/Matchbox/Phasespace/FIMassiveTildeKinematics.h"
#include "Herwig/MatrixElement/Matchbox/Phasespace/FIMassiveInvertedTildeKinematics.h"
using namespace Herwig;
FIMqgxDipole::FIMqgxDipole()
: SubtractionDipole() {}
IBPtr FIMqgxDipole::clone() const {
return new_ptr(*this);
}
IBPtr FIMqgxDipole::fullclone() const {
return new_ptr(*this);
}
bool FIMqgxDipole::canHandle(const cPDVector& partons,
int emitter, int emission, int spectator) const {
return
emitter > 1 && spectator < 2 &&
partons[emission]->id() == ParticleID::g &&
// abs(partons[emitter]->id()) < 7 &&
( abs(partons[emitter]->id()) < 7 || abs(partons[emitter]->id()) == 1000021 ) &&
partons[emitter]->hardProcessMass() != ZERO &&
partons[spectator]->hardProcessMass() == ZERO;
}
double FIMqgxDipole::me2Avg(double ccme2) const {
if ( jacobian() == 0.0 )
return 0.0;
double x = subtractionParameters()[0];
double z = subtractionParameters()[1];
Energy2 prop =
2.*((realEmissionME()->lastXComb().meMomenta()[realEmitter()])*
(realEmissionME()->lastXComb().meMomenta()[realEmission()]))*x;
double CF = (SM().Nc()*SM().Nc()-1.)/(2.*SM().Nc());
if ( realEmissionME()->lastXComb().mePartonData()[realEmitter()]->id() == 1000021 )
CF = SM().Nc(); // For the SUSY D_{gluino,g}^a subtraction dipole we need to replace CF by CA=Nc
// extra mass terms cancel
double res =
8.*Constants::pi*CF*(realEmissionME()->lastXComb().lastSHat())*
(underlyingBornME()->lastXComb().lastAlphaS())/prop;
// NOTE: extra term taken from FIqgxDipole implementation
// NOTE: extra term switched off for the moment in the massive case
res *= (
2./(1.-z+(1.-x)) - (1.+z)
// + (1.-x)*(1.+3.*x*z)
- sqr(realEmissionME()->lastXComb().mePartonData()[realEmitter()]->hardProcessMass()) / prop * 2.*x
);
res *= -ccme2;
res *=
pow(realEmissionME()->lastXComb().lastSHat() / underlyingBornME()->lastXComb().lastSHat(),
underlyingBornME()->lastXComb().mePartonData().size()-4.);
res *=
realEmissionME()->finalStateSymmetry() /
underlyingBornME()->finalStateSymmetry();
return res;
}
double FIMqgxDipole::me2() const {
if ( jacobian() == 0.0 )
return 0.0;
double x = subtractionParameters()[0];
double z = subtractionParameters()[1];
Energy2 prop =
2.*((realEmissionME()->lastXComb().meMomenta()[realEmitter()])*
(realEmissionME()->lastXComb().meMomenta()[realEmission()]))*x;
double CF = (SM().Nc()*SM().Nc()-1.)/(2.*SM().Nc());
if ( realEmissionME()->lastXComb().mePartonData()[realEmitter()]->id() == 1000021 )
CF = SM().Nc(); // For the SUSY D_{gluino,g}^a subtraction dipole we need to replace CF by CA=Nc
// extra mass terms cancel
double res =
8.*Constants::pi*CF*(realEmissionME()->lastXComb().lastSHat())*
(underlyingBornME()->lastXComb().lastAlphaS())/prop;
// NOTE: extra term taken from FIqgxDipole implementation
// NOTE: extra term switched off for the moment in the massive case
res *= (
2./(1.-z+(1.-x)) - (1.+z)
// + (1.-x)*(1.+3.*x*z)
- sqr(realEmissionME()->lastXComb().mePartonData()[realEmitter()]->hardProcessMass()) / prop * 2.*x
);
res *= -underlyingBornME()->colourCorrelatedME2(make_pair(bornEmitter(),bornSpectator()));
res *=
pow(realEmissionME()->lastXComb().lastSHat() / underlyingBornME()->lastXComb().lastSHat(),
underlyingBornME()->lastXComb().mePartonData().size()-4.);
res *=
realEmissionME()->finalStateSymmetry() /
underlyingBornME()->finalStateSymmetry();
return res;
}
void FIMqgxDipole::persistentOutput(PersistentOStream &) const {
}
void FIMqgxDipole::persistentInput(PersistentIStream &, int) {
}
void FIMqgxDipole::Init() {
static ClassDocumentation<FIMqgxDipole> documentation
("FIMqgxDipole");
// DipoleRepository::registerDipole<0,FIMqgxDipole,FILightTildeKinematics,FILightInvertedTildeKinematics>
// ("FIMqgxDipole","FILightTildeKinematics","FILightInvertedTildeKinematics");
DipoleRepository::registerDipole<0,FIMqgxDipole,FIMassiveTildeKinematics,FIMassiveInvertedTildeKinematics>
("FIMqgxDipole","FIMassiveTildeKinematics","FIMassiveInvertedTildeKinematics");
}
// *** Attention *** The following static variable is needed for the type
// description system in ThePEG. Please check that the template arguments
// are correct (the class and its base class), and that the constructor
// arguments are correct (the class name and the name of the dynamically
// loadable library where the class implementation can be found).
DescribeClass<FIMqgxDipole,SubtractionDipole>
describeHerwigFIMqgxDipole("Herwig::FIMqgxDipole", "Herwig.so");

File Metadata

Mime Type
text/x-c
Expires
Tue, Sep 30, 4:39 AM (15 h, 30 m)
Storage Engine
blob
Storage Format
Raw Data
Storage Handle
6564739
Default Alt Text
FIMqgxDipole.cc (5 KB)

Event Timeline

HEPForge.org · .