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MEvv2ss.cc
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MEvv2ss.cc
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// -*- C++ -*-
//
// This is the implementation of the non-inlined, non-templated member
// functions of the MEvv2ss class.
//
#include "MEvv2ss.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/VectorWaveFunction.h"
#include "ThePEG/Helicity/WaveFunction/ScalarWaveFunction.h"
#include "ThePEG/Helicity/WaveFunction/TensorWaveFunction.h"
#include "ThePEG/Helicity/Vertex/Scalar/VVSVertex.h"
#include "ThePEG/Helicity/Vertex/Scalar/VSSVertex.h"
#include "ThePEG/Helicity/Vertex/Vector/VVVVertex.h"
#include "ThePEG/Helicity/Vertex/Scalar/SSSVertex.h"
#include "ThePEG/Helicity/Vertex/Tensor/VVTVertex.h"
#include "ThePEG/Helicity/Vertex/Tensor/SSTVertex.h"
#include "ThePEG/Helicity/Vertex/Scalar/VVSSVertex.h"
#include <cassert>
using namespace Herwig;
using ThePEG::Helicity::VectorWaveFunction;
using ThePEG::Helicity::ScalarWaveFunction;
using ThePEG::Helicity::TensorWaveFunction;
using ThePEG::Helicity::VVSVertexPtr;
using ThePEG::Helicity::VSSVertex;
using ThePEG::Helicity::VVVVertexPtr;
using ThePEG::Helicity::SSSVertex;
using ThePEG::Helicity::VVTVertexPtr;
using ThePEG::Helicity::SSTVertexPtr;
using ThePEG::Helicity::VVSSVertex;
using ThePEG::Helicity::incoming;
using ThePEG::Helicity::outgoing;
double MEvv2ss::me2() const {
//setup wavefunctions
VectorWaveFunction vec1(meMomenta()[0],mePartonData()[0],incoming);
VectorWaveFunction vec2(meMomenta()[1],mePartonData()[1],incoming);
//2 is positve id, 3 is negative id
ScalarWaveFunction sca1(meMomenta()[2],mePartonData()[2],
Complex(1.,0.),outgoing);
ScalarWaveFunction sca2(meMomenta()[3],mePartonData()[3],
Complex(1.,0.),outgoing);
const HPCount ndiags(numberOfDiags());
const size_t ncf(numberOfFlows());
const Energy2 m2(scale());
const vector<vector<double> > cfactors = getColourFactors();
vector<double> me(ndiags,0.);
vector<Complex> flows(ncf, Complex(0.)), diag(ndiags, Complex(0.));
double full_me(0.);
ScalarWaveFunction interS; VectorWaveFunction interV;
TensorWaveFunction interT;
//keep location of contact diagram to zero me calc for this diagram
//so as not to add contact term to diagram selector
HPCount contact = ndiags;
//loop over vector helicities
for(unsigned int vhel1 = 0; vhel1 < 3; vhel1 += 2) {
vec1.reset(vhel1);
for(unsigned int vhel2 = 0; vhel2 < 3;vhel2 += 2) {
vec2.reset(vhel2);
//loop over diagrams
flows = vector<Complex>(ncf, Complex(0.));
for(HPCount ix = 0; ix < ndiags; ++ix){
HPDiagram current = getProcessInfo()[ix];
//do four-point diag first
if(current.channelType == HPDiagram::fourPoint) {
VVSSVertexPtr vert = dynamic_ptr_cast<VVSSVertexPtr>
(current.vertices.first);
diag[ix] = vert->evaluate(m2, vec1, vec2, sca1, sca2);
contact = ix;
}
else {
tcPDPtr offshell = current.intermediate;
if(current.channelType == HPDiagram::tChannel) {
VSSVertexPtr vert = dynamic_ptr_cast<VSSVertexPtr>
(current.vertices.first);
if(current.ordered.second) {
interS = vert->evaluate(m2, 3, offshell, vec1, sca1);
diag[ix] = vert->evaluate(m2, vec2, interS, sca2);
}
else {
interS = vert->evaluate(m2, 3, offshell, vec1, sca2);
diag[ix] = vert->evaluate(m2, vec2, interS, sca1);
}
}
else if(current.channelType == HPDiagram::sChannel) {
if(offshell->iSpin() == PDT::Spin1) {
VVVVertexPtr vert1 = dynamic_ptr_cast<VVVVertexPtr>
(current.vertices.first);
VSSVertexPtr vert2 = dynamic_ptr_cast<VSSVertexPtr>
(current.vertices.second);
interV = vert1->evaluate(m2, 1, offshell, vec1, vec2);
diag[ix] = vert2->evaluate(m2, interV, sca1, sca2);
}
else if(offshell->iSpin() == PDT::Spin2) {
VVTVertexPtr vert1 = dynamic_ptr_cast<VVTVertexPtr>
(current.vertices.first);
SSTVertexPtr vert2 = dynamic_ptr_cast<SSTVertexPtr>
(current.vertices.second);
interT = vert1->evaluate(m2, 1, offshell, vec1, vec2);
diag[ix] = vert2->evaluate(m2, sca1, sca2, interT);
}
}
else
diag[ix] = 0.;
}
me[ix] += norm(diag[ix]);
//colourflows
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
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();
}//vhel2 end
}//vhel1 end
DVector save(ndiags);
const double ifact = mePartonData()[2]->id() == mePartonData()[3]->id() ?
0.5 : 1.;
// contact must have been set during the loop run
assert(contact != ndiags);
me[contact] = 0.;
for(DVector::size_type ix = 0; ix < ndiags; ++ix)
save[ix] = ifact*me[ix]/256.;
meInfo(save);
return ifact*full_me/256.;
}
Selector<const ColourLines *>
MEvv2ss::colourGeometries(tcDiagPtr diag) const {
//88->33bar
static ColourLines cf1("1 4, -1 2 3, -3 -5");
static ColourLines cf2("-1 -5, 3 4, 1 2 -3");
static ColourLines cf3("1 3 4, -2 -3 -5, -1 2");
//88->11
static ColourLines cf4("1 -2, 2 -1");
HPDiagram current = getProcessInfo()[abs(diag->id()) - 1];
Selector<const ColourLines *> sel;
if(current.channelType == HPDiagram::tChannel ) {
if(current.ordered.second)
sel.insert(1., &cf1);
else
sel.insert(1., &cf2);
}
else if(current.channelType == HPDiagram::sChannel) {
if(mePartonData()[2]->iColour() == PDT::Colour0)
sel.insert(1., &cf4);
else
sel.insert(1., &cf3);
}
else
throw MEException() << "MEvv2ss::colourGeometries - "
<< "Cannot find correct colour configuration! \n"
<< Exception::warning;
return sel;
}
void MEvv2ss::persistentOutput(PersistentOStream &) const {
}
void MEvv2ss::persistentInput(PersistentIStream &, int) {
}
ClassDescription<MEvv2ss> MEvv2ss::initMEvv2ss;
// Definition of the static class description member.
void MEvv2ss::Init() {
static ClassDocumentation<MEvv2ss> documentation
("This class implements the ME for the vector-vector to scalar-scalar "
"hard-process");
}

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