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// -*- C++ -*-
//
// TensorWaveFunction.cc is a part of ThePEG - Toolkit for HEP Event Generation
// Copyright (C) 2003-2011 Peter Richardson, Leif Lonnblad
//
// ThePEG is licenced under version 2 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 TensorWaveFunction class.
//
// Author: Peter Richardson
//
#include "TensorWaveFunction.h"
using namespace ThePEG;
using namespace ThePEG::Helicity;
// calculate the actual wavefunction
void TensorWaveFunction::calculateWaveFunction(unsigned int ihel, TensorPhase tphase) {
int jhel=ihel-2;
assert(direction()!=intermediate);
// check for a valid helicty combination
assert((jhel<=2 && jhel>=-2 && mass() >ZERO) ||
((jhel==2 || jhel==-2) && mass()==ZERO));
// extract the momentum components
double fact = direction()==outgoing ? -1. : 1;
Energy ppx=fact*px(),ppy=fact*py(),ppz=fact*pz(),pee=fact*e(),pmm=mass();
// calculate some kinematic quantites;
Energy2 pt2 = sqr(ppx)+sqr(ppy);
Energy pabs = sqrt(pt2+sqr(ppz));
Energy pt = sqrt(pt2);
// polarization vectors
complex<double> epsp[4],epsm[4],eps0[4];
// + helicity vector if needed
if(jhel>=0) {
// calculate the overall phase
complex<double>phase;
if(tphase==tensor_phase) {
phase = pt==ZERO ? 1. : complex<double>(ppx/pt,-fact*ppy/pt);
}
else phase = 1.;
phase = phase*sqrt(0.5);
// first the no pt case
if(pt==ZERO) {
double sgnz = ppz<ZERO ? -1. : 1.;
epsp[0]=-phase;
epsp[1]= sgnz*phase*complex<double>(0,-fact);
epsp[2]=0.;
epsp[3]=0.;
}
else {
InvEnergy opabs=1./pabs;
InvEnergy opt =1./pt;
epsp[0]=phase*complex<double>(-ppz*ppx*opabs*opt,
fact*ppy*opt);
epsp[1]=phase*complex<double>(-ppz*ppy*opabs*opt,
-fact*ppx*opt);
epsp[2]=pt*opabs*phase;
epsp[3]=0.;
}
}
// - helicity vector if needed
if(jhel<=0) {
// calculate the overall phase
complex<double> phase;
if(tphase==tensor_phase) {
phase = pt==ZERO ? 1. : complex<double>(ppx/pt,fact*ppy/pt);
}
else phase = 1.;
phase = phase*sqrt(0.5);
// first the no pt case
if(pt==ZERO) {
double sgnz;
if(ppz<ZERO){sgnz=-1.;}
else{sgnz=1.;}
epsm[0]= phase;
epsm[1]= sgnz*phase*complex<double>(0,-fact);
epsm[2]=0.;
epsm[3]=0.;
}
else {
InvEnergy opabs=1./pabs;
InvEnergy opt =1./pt;
epsm[0]=phase*complex<double>(ppz*ppx*opabs*opt,
fact*ppy*opt);
epsm[1]=phase*complex<double>(ppz*ppy*opabs*opt,
-fact*ppx*opt);
epsm[2]=-pt*opabs*phase;
epsm[3]=0.;
}
}
// 0 helicity vector if needed
if(jhel<=1 && jhel>=-1) {
if(pabs==ZERO) {
eps0[0] = 0.;
eps0[1] = 0.;
eps0[2] = 1.;
eps0[3] = 0.;
}
else {
InvEnergy empabs=pee/pmm/pabs;
eps0[0] = empabs*ppx;
eps0[1] = empabs*ppy;
eps0[2] = empabs*ppz;
eps0[3] = pabs/pmm;
}
}
// put the polarization vectors together to get the wavefunction
double ort;
switch (jhel) {
case 2:
for(int ix=0;ix<4;++ix)
for(int iy=0;iy<4;++iy) _wf(ix,iy)=epsp[ix]*epsp[iy];
break;
case 1:
ort = sqrt(0.5);
for(int ix=0;ix<4;++ix)
for(int iy=0;iy<4;++iy) _wf(ix,iy)=ort*( epsp[ix]*eps0[iy]+
eps0[ix]*epsp[iy]);
break;
case 0:
ort = 1./sqrt(6.);
for(int ix=0;ix<4;++ix)
for(int iy=0;iy<4;++iy) _wf(ix,iy)=ort*( epsp[ix]*epsm[iy]
+ epsm[ix]*epsp[iy]
+2.*eps0[ix]*eps0[iy]);
break;
case -1:
ort = 1./sqrt(2.);
for(int ix=0;ix<4;++ix)
for(int iy=0;iy<4;++iy) _wf(ix,iy)=ort*( epsm[ix]*eps0[iy]+
eps0[ix]*epsm[iy]);
break;
case -2:
for(int ix=0;ix<4;++ix)
for(int iy=0;iy<4;++iy) _wf(ix,iy)=epsm[ix]*epsm[iy];
break;
default:
ThePEG::Helicity::HelicityConsistencyError()
<< "Invalid Helicity = " << jhel << " requested for Tensor"
<< Exception::abortnow;
break;
}
}
void TensorWaveFunction::
calculateWaveFunctions(vector<LorentzTensor<double> > & waves,
tPPtr particle,Direction dir, bool massless,
TensorPhase phase) {
tTensorSpinPtr inspin = !particle->spinInfo() ? tTensorSpinPtr() :
dynamic_ptr_cast<tTensorSpinPtr>(particle->spinInfo());
waves.resize(5);
if(inspin) {
if(dir==outgoing) {
for(unsigned int ix=0;ix<5;++ix)
waves[ix]=inspin->getProductionBasisState(ix);
}
else {
inspin->decay();
for(unsigned int ix=0;ix<5;++ix)
waves[ix]=inspin->getDecayBasisState(ix);
}
}
else {
assert(!particle->spinInfo());
TensorWaveFunction wave(particle->momentum(),particle->dataPtr(),0,
dir,phase);
for(unsigned int ix=0;ix<5;++ix) {
if(massless&&ix>0&&ix<5) {
waves[ix] = LorentzTensor<double>();
}
else {
if(ix!=0) wave.reset(ix);
waves[ix] = wave.wave();
}
}
}
}
void TensorWaveFunction::
calculateWaveFunctions(vector<TensorWaveFunction> & waves,
tPPtr particle, Direction dir, bool massless,
TensorPhase phase) {
tTensorSpinPtr inspin = !particle->spinInfo() ? tTensorSpinPtr() :
dynamic_ptr_cast<tTensorSpinPtr>(particle->spinInfo());
waves.resize(5);
if(inspin) {
if(dir==outgoing) {
for(unsigned int ix=0;ix<5;++ix)
waves[ix]=TensorWaveFunction(particle->momentum(),
particle->dataPtr(),
inspin->getProductionBasisState(ix),dir);
}
else {
inspin->decay();
for(unsigned int ix=0;ix<5;++ix)
waves[ix]=TensorWaveFunction(particle->momentum(),
particle->dataPtr(),
inspin->getDecayBasisState(ix),dir);
}
}
else {
assert(!particle->spinInfo());
TensorWaveFunction wave(particle->momentum(),particle->dataPtr(),0,
dir,phase);
for(unsigned int ix=0;ix<5;++ix) {
if(massless&&ix>0&&ix<5) {
waves[ix] = TensorWaveFunction(particle->momentum(),particle->dataPtr(),dir);
}
else {
if(ix!=0) wave.reset(ix);
waves[ix] = wave;
}
}
}
}
void TensorWaveFunction::
calculateWaveFunctions(vector<LorentzTensor<double> > & waves,
RhoDMatrix & rho,
tPPtr particle,Direction dir,bool massless,
TensorPhase phase) {
tTensorSpinPtr inspin = !particle->spinInfo() ? tTensorSpinPtr() :
dynamic_ptr_cast<tTensorSpinPtr>(particle->spinInfo());
waves.resize(5);
if(inspin) {
if(dir==outgoing) {
for(unsigned int ix=0;ix<5;++ix)
waves[ix]=inspin->getProductionBasisState(ix);
rho = RhoDMatrix(PDT::Spin2);
}
else {
inspin->decay();
for(unsigned int ix=0;ix<5;++ix)
waves[ix]=inspin->getDecayBasisState(ix);
rho = inspin->rhoMatrix();
}
}
else {
assert(!particle->spinInfo());
TensorWaveFunction wave(particle->momentum(),particle->dataPtr(),0,
dir,phase);
for(unsigned int ix=0;ix<5;++ix) {
if(massless&&ix>0&&ix<5) {
waves[ix] = LorentzTensor<double>();
}
else {
if(ix!=0) wave.reset(ix);
waves[ix] = wave.wave();
}
}
rho = RhoDMatrix(PDT::Spin2);
}
}
void TensorWaveFunction::
calculateWaveFunctions(vector<TensorWaveFunction> & waves,
RhoDMatrix & rho,
tPPtr particle, Direction dir, bool massless,
TensorPhase phase) {
tTensorSpinPtr inspin = !particle->spinInfo() ? tTensorSpinPtr() :
dynamic_ptr_cast<tTensorSpinPtr>(particle->spinInfo());
waves.resize(5);
if(inspin) {
if(dir==outgoing) {
for(unsigned int ix=0;ix<5;++ix)
waves[ix]=TensorWaveFunction(particle->momentum(),
particle->dataPtr(),
inspin->getProductionBasisState(ix),dir);
rho = RhoDMatrix(PDT::Spin2);
}
else {
inspin->decay();
for(unsigned int ix=0;ix<5;++ix)
waves[ix]=TensorWaveFunction(particle->momentum(),
particle->dataPtr(),
inspin->getDecayBasisState(ix),dir);
rho = inspin->rhoMatrix();
}
}
else {
assert(!particle->spinInfo());
TensorWaveFunction wave(particle->momentum(),particle->dataPtr(),0,
dir,phase);
for(unsigned int ix=0;ix<5;++ix) {
if(massless&&ix>0&&ix<5) {
waves[ix] = TensorWaveFunction(particle->momentum(),particle->dataPtr(),dir);
}
else {
if(ix!=0) wave.reset(ix);
waves[ix] = wave;
}
}
rho = RhoDMatrix(PDT::Spin2);
}
}
void TensorWaveFunction::
constructSpinInfo(const vector<LorentzTensor<double> > & waves,
tPPtr part,Direction dir, bool time,bool ) {
assert(waves.size()==5);
tTensorSpinPtr inspin = !part->spinInfo() ? tTensorSpinPtr() :
dynamic_ptr_cast<tTensorSpinPtr>(part->spinInfo());
if(inspin) {
for(unsigned int ix=0;ix<5;++ix)
if(dir==outgoing) inspin->setBasisState(ix,waves[ix]);
else inspin->setDecayState(ix,waves[ix]);
}
else {
TensorSpinPtr temp = new_ptr(TensorSpinInfo(part->momentum(),time));
part->spinInfo(temp);
for(unsigned int ix=0;ix<5;++ix)
if(dir==outgoing) temp->setBasisState(ix,waves[ix]);
else temp->setDecayState(ix,waves[ix]);
}
}
void TensorWaveFunction::
constructSpinInfo(const vector<TensorWaveFunction> & waves,
tPPtr part,Direction dir, bool time,bool ) {
assert(waves.size()==5);
tTensorSpinPtr inspin = !part->spinInfo() ? tTensorSpinPtr() :
dynamic_ptr_cast<tTensorSpinPtr>(part->spinInfo());
if(inspin) {
for(unsigned int ix=0;ix<5;++ix)
if(dir==outgoing) inspin->setBasisState(ix,waves[ix].wave());
else inspin->setDecayState(ix,waves[ix].wave());
}
else {
TensorSpinPtr temp = new_ptr(TensorSpinInfo(part->momentum(),time));
part->spinInfo(temp);
for(unsigned int ix=0;ix<5;++ix)
if(dir==outgoing) temp->setBasisState(ix,waves[ix].wave());
else temp->setDecayState(ix,waves[ix].wave());
}
}
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