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diff --git a/Shower/SplittingFunctions/HalfHalfOneEWSplitFn.cc b/Shower/SplittingFunctions/HalfHalfOneEWSplitFn.cc
--- a/Shower/SplittingFunctions/HalfHalfOneEWSplitFn.cc
+++ b/Shower/SplittingFunctions/HalfHalfOneEWSplitFn.cc
@@ -1,214 +1,216 @@
// -*- C++ -*-
//
// This is the implementation of the non-inlined, non-templated member
// functions of the HalfHalfOneEWSplitFn class.
//
#include "HalfHalfOneEWSplitFn.h"
#include "ThePEG/StandardModel/StandardModelBase.h"
#include "ThePEG/Repository/EventGenerator.h"
#include "ThePEG/Interface/ClassDocumentation.h"
#include "ThePEG/Utilities/DescribeClass.h"
#include "ThePEG/Persistency/PersistentOStream.h"
#include "ThePEG/Persistency/PersistentIStream.h"
#include "ThePEG/PDT/ParticleData.h"
#include "Herwig/Decay/TwoBodyDecayMatrixElement.h"
using namespace Herwig;
IBPtr HalfHalfOneEWSplitFn::clone() const {
return new_ptr(*this);
}
IBPtr HalfHalfOneEWSplitFn::fullclone() const {
return new_ptr(*this);
}
void HalfHalfOneEWSplitFn::persistentOutput(PersistentOStream & os) const {
os << gZ_ << gWL_;
}
void HalfHalfOneEWSplitFn::persistentInput(PersistentIStream & is, int) {
is >> gZ_ >> gWL_;
}
// The following static variable is needed for the type description system in ThePEG.
DescribeClass<HalfHalfOneEWSplitFn,SplittingFunction>
describeHerwigHalfHalfOneEWSplitFn("Herwig::HalfHalfOneEWSplitFn", "HwShower.so");
void HalfHalfOneEWSplitFn::Init() {
static ClassDocumentation<HalfHalfOneEWSplitFn> documentation
("The HalfHalfOneEWSplitFn class implements the splitting q->qWand q->qZ");
}
void HalfHalfOneEWSplitFn::doinit() {
SplittingFunction::doinit();
tcSMPtr sm = generator()->standardModel();
double sw2 = sm->sin2ThetaW();
// left-handled W coupling
gWL_ = 1./sqrt(2.*sw2);
// Z couplings
double fact = 0.25/sqrt(sw2*(1.-sw2));
for(int ix=1;ix<4;++ix) {
gZ_[2*ix-1] = make_pair(fact*(sm->vd() + sm->ad()),
fact*(sm->vd() - sm->ad() ));
gZ_[2*ix ] = make_pair(fact*(sm->vu() + sm->au() ),
fact*(sm->vu() - sm->au() ));
gZ_[2*ix+9 ] = make_pair(fact*(sm->ve() + sm->ae() ),
fact*(sm->ve() - sm->ae() ));
gZ_[2*ix+10] = make_pair(fact*(sm->vnu() + sm->anu()),
fact*(sm->vnu() - sm->anu()));
}
}
void HalfHalfOneEWSplitFn::getCouplings(double & gL, double & gR, const IdList & ids) const {
if(ids[2]->id()==ParticleID::Z0) {
map<long,pair<double,double> >::const_iterator it = gZ_.find(abs(ids[0]->id()));
assert(it!=gZ_.end());
gL = it->second.first ;
gR = it->second.second;
}
else if(abs(ids[2]->id())==ParticleID::Wplus) {
gL = gWL_;
}
else
assert(false);
+ if(ids[0]->id()<0) swap(gL,gR);
}
double HalfHalfOneEWSplitFn::P(const double z, const Energy2 t,
const IdList &ids, const bool mass, const RhoDMatrix & rho) const {
double gL(0.),gR(0.);
getCouplings(gL,gR,ids);
double val = (1. + sqr(z))/(1.-z);
if(mass) {
Energy m = ids[2]->mass();
val -= sqr(m)/t;
}
val *= (sqr(gL)*norm(rho(0,0))+sqr(gR)*norm(rho(1,1)));
return colourFactor(ids)*val;
}
double HalfHalfOneEWSplitFn::overestimateP(const double z,
const IdList & ids) const {
double gL(0.),gR(0.);
getCouplings(gL,gR,ids);
- return 2.*sqr(max(gL,gR))*colourFactor(ids)/(1.-z);
+ return 2.*max(sqr(gL),sqr(gR))*colourFactor(ids)/(1.-z);
}
double HalfHalfOneEWSplitFn::ratioP(const double z, const Energy2 t,
- const IdList & ids, const bool mass, const RhoDMatrix & rho) const {
+ const IdList & ids, const bool mass,
+ const RhoDMatrix & rho) const {
double gL(0.),gR(0.);
getCouplings(gL,gR,ids);
double val = 1. + sqr(z);
if(mass) {
Energy m = ids[2]->mass();
val -= (1.-z)*sqr(m)/t;
}
- val *= (sqr(gL)*norm(rho(0,0))+sqr(gR)*norm(rho(1,1)));
- return val;
+ val *= (sqr(gL)*abs(rho(0,0))+sqr(gR)*abs(rho(1,1)))/max(sqr(gL),sqr(gR));
+ return 0.5*val;
}
double HalfHalfOneEWSplitFn::integOverP(const double z,
const IdList & ids,
unsigned int PDFfactor) const {
double gL(0.),gR(0.);
getCouplings(gL,gR,ids);
- double pre = colourFactor(ids)*sqr(max(gL,gR));
+ double pre = colourFactor(ids)*max(sqr(gL),sqr(gR));
switch (PDFfactor) {
case 0:
return -2.*pre*Math::log1m(z);
case 1:
return 2.*pre*log(z/(1.-z));
case 2:
return 2.*pre/(1.-z);
case 3:
default:
throw Exception() << "HalfHalfOneEWSplitFn::integOverP() invalid PDFfactor = "
<< PDFfactor << Exception::runerror;
}
}
double HalfHalfOneEWSplitFn::invIntegOverP(const double r, const IdList & ids,
unsigned int PDFfactor) const {
double gL(0.),gR(0.);
getCouplings(gL,gR,ids);
- double pre = colourFactor(ids)*sqr(max(gL,gR));
+ double pre = colourFactor(ids)*max(sqr(gL),sqr(gR));
switch (PDFfactor) {
case 0:
return 1. - exp(- 0.5*r/pre);
case 1:
return 1./(1.-exp(-0.5*r/pre));
case 2:
return 1.-2.*pre/r;
case 3:
default:
throw Exception() << "HalfHalfOneEWSplitFn::invIntegOverP() invalid PDFfactor = "
<< PDFfactor << Exception::runerror;
}
}
bool HalfHalfOneEWSplitFn::accept(const IdList &ids) const {
if(ids.size()!=3) return false;
if(ids[2]->id()==ParticleID::Z0) {
if(ids[0]->id()==ids[1]->id() &&
((ids[0]->id()>=1 && ids[0]->id()<=6) || (ids[0]->id()>=11&&ids[0]->id()<=16) )) return true;
}
else if(abs(ids[2]->id())==ParticleID::Wplus) {
if(!((ids[0]->id()>=1 && ids[0]->id()<=6) || (ids[0]->id()>=11&&ids[0]->id()<=16) )) return false;
if(!((ids[1]->id()>=1 && ids[1]->id()<=6) || (ids[1]->id()>=11&&ids[1]->id()<=16) )) return false;
if(ids[0]->id()+1!=ids[1]->id() && ids[0]->id()-1!=ids[1]->id()) return false;
int out = ids[1]->iCharge()+ids[2]->iCharge();
if(ids[0]->iCharge()==out) return true;
}
return false;
}
vector<pair<int, Complex> >
HalfHalfOneEWSplitFn::generatePhiForward(const double, const Energy2, const IdList & ,
const RhoDMatrix &) {
// no dependence on the spin density matrix, dependence on off-diagonal terms cancels
// and rest = splitting function for Tr(rho)=1 as required by defn
return vector<pair<int, Complex> >(1,make_pair(0,1.));
}
vector<pair<int, Complex> >
HalfHalfOneEWSplitFn::generatePhiBackward(const double, const Energy2, const IdList & ,
const RhoDMatrix &) {
// no dependence on the spin density matrix, dependence on off-diagonal terms cancels
// and rest = splitting function for Tr(rho)=1 as required by defn
return vector<pair<int, Complex> >(1,make_pair(0,1.));
}
DecayMEPtr HalfHalfOneEWSplitFn::matrixElement(const double z, const Energy2 t,
const IdList & ids, const double phi,
bool) {
// calculate the kernal
DecayMEPtr kernal(new_ptr(TwoBodyDecayMatrixElement(PDT::Spin1Half,PDT::Spin1Half,PDT::Spin1)));
Energy m = ids[2]->mass();
double gL(0.),gR(0.);
getCouplings(gL,gR,ids);
double mt = m/sqrt(t);
double root = sqrt(1.-sqr(m)/t/(1-z));
double romz = sqrt(1.-z);
double rz = sqrt(z);
double r2 = sqrt(2.);
Complex phase = exp(Complex(0.,1.)*phi);
Complex cphase = conj(phase);
(*kernal)(0,0,0) = -phase*root*gL/romz;
(*kernal)(1,1,2) = cphase*root*gR/romz;
(*kernal)(0,0,2) = cphase*z*root*gL/romz;
(*kernal)(1,1,0) = -phase*z*root*gR/romz;
// long terms
(*kernal)(1,1,1) =-gR*mt*r2*rz/(1-z);
(*kernal)(0,0,1) =-gL*mt*r2*rz/(1-z);
// +- -+ terms zero due quark mass
for(unsigned int ix=0;ix<3;++ix) {
(*kernal)(1,0,ix) = 0.;
(*kernal)(0,1,ix) = 0.;
}
// return the answer
return kernal;
}

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