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diff --git a/Shower/QTilde/SplittingFunctions/OneOneZeroEWSplitFn.cc b/Shower/QTilde/SplittingFunctions/OneOneZeroEWSplitFn.cc
--- a/Shower/QTilde/SplittingFunctions/OneOneZeroEWSplitFn.cc
+++ b/Shower/QTilde/SplittingFunctions/OneOneZeroEWSplitFn.cc
@@ -1,216 +1,211 @@
// -*- C++ -*-
//
// This is the implementation of the non-inlined, non-templated member
// functions of the OneOneZeroEWSplitFn class.
//
#include "OneOneZeroEWSplitFn.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"
#include "Herwig/Models/StandardModel/SMFFHVertex.h"
using namespace Herwig;
IBPtr OneOneZeroEWSplitFn::clone() const {
return new_ptr(*this);
}
IBPtr OneOneZeroEWSplitFn::fullclone() const {
return new_ptr(*this);
}
void OneOneZeroEWSplitFn::persistentOutput(PersistentOStream & os) const {
os << gWWH_ << gZZH_ << _theSM;
}
void OneOneZeroEWSplitFn::persistentInput(PersistentIStream & is, int) {
is >> gWWH_ >> gZZH_ >> _theSM;
}
// The following static variable is needed for the type description system in ThePEG.
DescribeClass<OneOneZeroEWSplitFn,SplittingFunction>
describeHerwigOneOneZeroEWSplitFn("Herwig::OneOneZeroEWSplitFn", "HwShower.so");
void OneOneZeroEWSplitFn::Init() {
static ClassDocumentation<OneOneZeroEWSplitFn> documentation
("The OneOneZeroEWSplitFn class implements the splittings W->WH and Z->ZH");
}
void OneOneZeroEWSplitFn::doinit() {
SplittingFunction::doinit();
tcSMPtr sm = generator()->standardModel();
double sw2 = sm->sin2ThetaW();
// W -> W H coupling g = e/sin theta_W
gWWH_ = 1./sqrt(sw2);
// Z -> Z H coupling
gZZH_ = 1./(sqrt(sw2)*sqrt(1.-sw2));
// to employ running masses, wherever needed
_theSM = dynamic_ptr_cast<tcHwSMPtr>(generator()->standardModel());
}
void OneOneZeroEWSplitFn::getCouplings(double & g, const IdList & ids) const {
if(abs(ids[0]->id())==ParticleID::Wplus){
g = gWWH_;
}
else if(ids[0]->id()==ParticleID::Z0){
g = gZZH_;
}
else
assert(false);
}
double OneOneZeroEWSplitFn::P(const double z, const Energy2 t,
const IdList &ids, const bool mass, const RhoDMatrix & rho) const {
double gvvh(0.);
getCouplings(gvvh,ids);
double rho00 = abs(rho(0,0));
double rho11 = abs(rho(1,1));
double rho22 = abs(rho(2,2));
// the splitting in the massless limit
- double val = ((1.-z)/z)*(2.*rho11+sqr(z)*(rho00+rho22));
+ double val = 0.;
// the massive limit
if(mass){
// get the running mass
double m0t = _theSM->mass(t,getParticleData(ids[0]->id()))/sqrt(t);
- double m2t = _theSM->mass(t,getParticleData(ids[2]->id()))/sqrt(t);
- val += -sqr(m2t)*((2.*rho11)/z+z*(rho00+rho22));
- val += -sqr(m0t)*(((2.*z-4.)*rho11)/z-(1.+(2.-z)*z)*(rho00+rho22));
+ val += (2./sqr(z))*sqr(m0t)*(rho11+sqr(z)*(rho00+rho22));
}
return sqr(gvvh)*val;
}
double OneOneZeroEWSplitFn::overestimateP(const double z,
const IdList & ids) const {
double gvvh(0.);
getCouplings(gvvh,ids);
- return sqr(gvvh)*(2./z);
+ return sqr(gvvh)*(2./sqr(z));
}
double OneOneZeroEWSplitFn::ratioP(const double z, const Energy2 t,
const IdList & ids, const bool mass,
const RhoDMatrix & rho) const {
double rho00 = abs(rho(0,0));
double rho11 = abs(rho(1,1));
double rho22 = abs(rho(2,2));
// ratio in the massless limit
- double val = (1.-z)*(2.*rho11+sqr(z)*(rho00+rho22))/2.;
+ double val = 0.;
// the massive limit
if(mass){
// get the running mass
double m0t = _theSM->mass(t,getParticleData(ids[0]->id()))/sqrt(t);
- double m2t = _theSM->mass(t,getParticleData(ids[2]->id()))/sqrt(t);
- val += -sqr(m2t)*0.5*z*((2.*rho11)/z+(rho00+rho22)*z);
- val += -sqr(m0t)*0.5*z*((rho11*(-4.+2.*z))/z-(rho00+rho22)*(1.+(2.-z)*z));
+ val += sqr(m0t)*(rho11+sqr(z)*(rho00+rho22));
}
return val;
}
-
double OneOneZeroEWSplitFn::integOverP(const double z,
const IdList & ids,
unsigned int PDFfactor) const {
double gvvh(0.);
getCouplings(gvvh,ids);
double pre = sqr(gvvh);
switch (PDFfactor) {
case 0:
- return 2.*pre*log(z);
+ return -pre*(2./z);
case 1:
case 2:
case 3:
default:
throw Exception() << "OneOneZeroEWSplitFn::integOverP() invalid PDFfactor = "
<< PDFfactor << Exception::runerror;
}
}
double OneOneZeroEWSplitFn::invIntegOverP(const double r, const IdList & ids,
unsigned int PDFfactor) const {
double gvvh(0.);
getCouplings(gvvh,ids);
double pre = sqr(gvvh);
switch (PDFfactor) {
case 0:
- return exp(r/(2.*pre));
+ return -pre*(2./r);
case 1:
case 2:
case 3:
default:
throw Exception() << "OneOneZeroEWSplitFn::invIntegOverP() invalid PDFfactor = "
<< PDFfactor << Exception::runerror;
}
}
bool OneOneZeroEWSplitFn::accept(const IdList &ids) const {
if(ids.size()!=3)
return false;
if(ids[0]->id()!=ids[1]->id())
return false;
if(abs(ids[0]->id())==ParticleID::Wplus && ids[2]->id()==ParticleID::h0)
return true;
else if(ids[0]->id()==ParticleID::Z0 && ids[2]->id()==ParticleID::h0)
return true;
else
return false;
}
vector<pair<int, Complex> >
OneOneZeroEWSplitFn::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> >
OneOneZeroEWSplitFn::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 OneOneZeroEWSplitFn::matrixElement(const double z, const Energy2 t,
const IdList & ids, const double phi,
bool) {
double gvvh(0.);
getCouplings(gvvh,ids);
// calculate the kernal
DecayMEPtr kernal(new_ptr(TwoBodyDecayMatrixElement(PDT::Spin1,PDT::Spin1,PDT::Spin0)));
Complex phase = exp(Complex(0.,1.)*phi);
Complex cphase = conj(phase);
double r2 = sqrt(2.);
double m0t = _theSM->mass(t,getParticleData(ids[0]->id()))/sqrt(t);
double m2t = _theSM->mass(t,getParticleData(ids[2]->id()))/sqrt(t);
double sqrtmass = sqrt(sqr(m0t)-sqr(m0t)/z-sqr(m2t)/(1.-z)+1.);
// assign kernel
(*kernal)(0,0,0) = -gvvh*r2*m0t; // 111
- (*kernal)(0,1,0) = -gvvh*cphase*sqrt((1.-z)*z)*sqrtmass; // 121
+ (*kernal)(0,1,0) = 0.; // 121
(*kernal)(0,2,0) = 0.; // 131
- (*kernal)(1,0,0) = gvvh*phase*sqrt((1.-z)/z)*sqrtmass; // 211
- (*kernal)(1,1,0) = 0.; // 221 > 441
- (*kernal)(1,2,0) = -gvvh*cphase*sqrt((1.-z)/z)*sqrtmass; // 231
+ (*kernal)(1,0,0) = 0.; // 211
+ (*kernal)(1,1,0) = -gvvh*r2*m0t/z; // 221 > 241
+ (*kernal)(1,2,0) = 0.; // 231
(*kernal)(2,0,0) = 0.; // 311
- (*kernal)(2,1,0) = gvvh*phase*sqrt((1.-z)*z)*sqrtmass; // 321 > 341
+ (*kernal)(2,1,0) = 0.; // 321 > 341
(*kernal)(2,2,0) = -gvvh*r2*m0t; // 331
// return the answer
return kernal;
}

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