Page MenuHomeHEPForge
Files F19244543

MEff2vv.cc
No OneTemporary
Actions

Size
7 KB
Referenced Files
None
Subscribers
None

MEff2vv.cc
View Options

// -*- C++ -*-
//
// This is the implementation of the non-inlined, non-templated member
// functions of the MEff2vv class.
//
#include "MEff2vv.h"
#include "ThePEG/Interface/ClassDocumentation.h"
#include "ThePEG/Persistency/PersistentOStream.h"
#include "ThePEG/Persistency/PersistentIStream.h"
#include "ThePEG/Handlers/StandardXComb.h"
#include "ThePEG/Helicity/WaveFunction/SpinorWaveFunction.h"
#include "ThePEG/Helicity/WaveFunction/SpinorBarWaveFunction.h"
#include "ThePEG/Helicity/WaveFunction/VectorWaveFunction.h"
#include "ThePEG/Helicity/WaveFunction/TensorWaveFunction.h"
using namespace Herwig;
using ThePEG::Helicity::ScalarWaveFunction;
using ThePEG::Helicity::SpinorWaveFunction;
using ThePEG::Helicity::SpinorBarWaveFunction;
using ThePEG::Helicity::VectorWaveFunction;
using ThePEG::Helicity::TensorWaveFunction;
using ThePEG::Helicity::FFVVertexPtr;
using ThePEG::Helicity::FFTVertexPtr;
using ThePEG::Helicity::FFSVertexPtr;
using ThePEG::Helicity::VVSVertexPtr;
using ThePEG::Helicity::GeneralSVVVertexPtr;
using ThePEG::Helicity::VVTVertex;
using ThePEG::Helicity::VVVVertexPtr;
using ThePEG::Helicity::incoming;
using ThePEG::Helicity::outgoing;
typedef Ptr<VVTVertex>::pointer VVTVertexPtr;
double MEff2vv::me2() const {
//Define wavefunctions
SpinorWaveFunction spIn(meMomenta()[0], mePartonData()[0], incoming);
SpinorBarWaveFunction spbIn(meMomenta()[1], mePartonData()[1], incoming);
VectorWaveFunction vec1(meMomenta()[2], mePartonData()[2], outgoing);
VectorWaveFunction vec2(meMomenta()[3], mePartonData()[3], outgoing);
//Massless vectors?
bool masslC = (mePartonData()[2]->mass() == 0.*MeV);
bool masslD = (mePartonData()[3]->mass() == 0.*MeV);
//Define vectors to store diagrams and square elements
const HPCount ndiags(numberOfDiags());
const size_t ncf(numberOfFlows());
vector<Complex> diag(ndiags, Complex(0.));
vector<double> me(ndiags, 0.);
double full_me(0.);
const Energy2 m2 = scale();
const vector<vector<double> > cfactors = getColourFactors();
//Intermediate wavefunctions
ScalarWaveFunction interS; SpinorWaveFunction interF;
VectorWaveFunction interV; TensorWaveFunction interT;
//Loop over helicities and calculate diagrams
for(unsigned int fhel1 = 0; fhel1 < 2; ++fhel1) {
spIn.reset(fhel1);
for(unsigned int fhel2 = 0; fhel2 < 2; ++fhel2) {
spbIn.reset(fhel2);
for(unsigned int vhel1 = 0; vhel1 < 3; ++vhel1) {
if(vhel1 == 1 && masslC) ++vhel1;
vec1.reset(vhel1);
for(unsigned int vhel2 = 0; vhel2 < 3; ++vhel2) {
if(vhel2 == 1 && masslD) ++vhel2;
vec2.reset(vhel2);
//loop and calculate diagrams
vector<Complex> flows = vector<Complex>(2, Complex(0.));
for(HPCount ix = 0; ix < ndiags; ++ix) {
HPDiagram current = getProcessInfo()[ix];
tcPDPtr offshell = current.intermediate;
if(current.channelType == HPDiagram::tChannel) {
if(current.intermediate->iSpin() == PDT::Spin1Half) {
if(current.ordered.second) {
interF = theFerm[ix].first->evaluate(m2, 3, offshell, spIn,
vec1);
diag[ix] = theFerm[ix].second->evaluate(m2, interF, spbIn,
vec2);
}
else {
interF = theFerm[ix].first->evaluate(m2, 3, offshell, spIn,
vec2);
diag[ix] = theFerm[ix].second->evaluate(m2, interF, spbIn,
vec1);
}
}
}
else {
if(current.intermediate->iSpin() == PDT::Spin0) {
if(masslC && masslD) {
interS = theSca1[ix].first->evaluate(m2, 1, offshell,
spIn, spbIn);
diag[ix] = theSca1[ix].second->evaluate(m2, interS, vec1, vec2);
}
else {
interS = theSca2[ix].first->evaluate(m2, 1, offshell,
spIn, spbIn);
diag[ix] = theSca2[ix].second->evaluate(m2, vec1, vec2, interS);
}
}
else if(current.intermediate->iSpin() == PDT::Spin1) {
interV = theVec[ix].first->evaluate(m2, 1, offshell, spIn, spbIn);
diag[ix] = theVec[ix].second->evaluate(m2, vec1, vec2, interV);
}
else {
interT = theTen[ix].first->evaluate(m2, 1, offshell, spIn, spbIn);
diag[ix] = theTen[ix].second->evaluate(m2, vec1, vec2, interT);
}
}
//compute individual diagram squared and save for diagram sel
me[ix] += norm(diag[ix]);
//find out which colourflow this diag belongs to and add to it
for(size_t iy = 0; iy < current.colourFlow.size(); ++iy)
flows[current.colourFlow[iy].first - 1] +=
current.colourFlow[iy].second*diag[ix];
}//end-of-diagram loop
//Add results, with appropriate colour factors to full_me
for(size_t ii = 0; ii < ncf; ++ii)
for(size_t ij = 0; ij < ncf; ++ij)
full_me += cfactors[ii][ij]*(flows[ii]*conj(flows[ij])).real();
}
}
}
}
const double cAvg = mePartonData()[0]->coloured() ? 1./9. : 1.;
const double ifact = mePartonData()[2]->id() == mePartonData()[3]->id() ?
0.5 : 1;
DVector save(ndiags);
for(DVector::size_type idx = 0; idx < ndiags; ++idx)
save[idx] = 0.25*cAvg*ifact*me[idx];
meInfo(save);
full_me *= 0.25*cAvg*ifact;
return full_me;
}
Selector<const ColourLines *>
MEff2vv::colourGeometries(tcDiagPtr diag) const {
static vector<ColourLines> cf(9);
//33b->11
cf[0] = ColourLines("1 2 -3");
cf[1] = ColourLines("1 -2");
//33b->88
cf[2] = ColourLines("1 4, -4 2 5, -5 -3");
cf[3] = ColourLines("1 5, -5 2 4, -4 -3");
cf[4] = ColourLines("1 3 4, -5 -3 -2, -4 5");
cf[5] = ColourLines("1 3 5, -4 -3 -2, -5 4");
cf[6] = ColourLines("1 -2, 4 -5, 5 -4");
//33b->81
cf[7] = ColourLines("1 4, -4 2 -3");
cf[8] = ColourLines("1 2 5, -5 -3");
HPDiagram current = getProcessInfo()[abs(diag->id()) - 1];
vector<ColourLines>::size_type cl(0);
if(mePartonData()[2]->iColour() == PDT::Colour8 &&
mePartonData()[3]->iColour() == PDT::Colour8 ) {
if(current.channelType == HPDiagram::tChannel)
cl = current.ordered.second ? 2 : 3;
else {
if(current.intermediate->iColour() == PDT::Colour0)
cl = 6;
else
cl = 4 + rnd2(0.5, 0.5);
}
}
else if(mePartonData()[2]->iColour() == PDT::Colour0 &&
mePartonData()[3]->iColour() == PDT::Colour0 )
cl = (current.channelType == HPDiagram::tChannel) ? 0 : 1;
else if(mePartonData()[2]->iColour() == PDT::Colour8 &&
mePartonData()[3]->iColour() == PDT::Colour0 )
cl = (current.channelType == HPDiagram::tChannel) ? 7 : 8;
else if(mePartonData()[2]->iColour() == PDT::Colour0 &&
mePartonData()[3]->iColour() == PDT::Colour8 )
cl = (current.channelType == HPDiagram::tChannel) ? 8 : 7;
else {
return Selector<const ColourLines *>();
}
Selector<const ColourLines *> sel;
sel.insert(1., &cf[cl]);
return sel;
}
void MEff2vv::persistentOutput(PersistentOStream & os) const {
os << theFerm << theVec << theTen << theSca1 << theSca2;
}
void MEff2vv::persistentInput(PersistentIStream & is, int) {
is >> theFerm >> theVec >> theTen >> theSca1 >> theSca2;
}
ClassDescription<MEff2vv> MEff2vv::initMEff2vv;
// Definition of the static class description member.
void MEff2vv::Init() {
static ClassDocumentation<MEff2vv> documentation
("This class implements the matrix element calculation of the 2->2 "
"process, fermion-antifermion -> vector vector");
}

File Metadata

Mime Type
text/x-c
Expires
Tue, Sep 30, 4:43 AM (1 d, 19 h)
Storage Engine
blob
Storage Format
Raw Data
Storage Handle
6498034
Default Alt Text
MEff2vv.cc (7 KB)

Event Timeline

HEPForge.org · .