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diff --git a/MatrixElement/DIS/MEChargedCurrentDIS.cc b/MatrixElement/DIS/MEChargedCurrentDIS.cc
--- a/MatrixElement/DIS/MEChargedCurrentDIS.cc
+++ b/MatrixElement/DIS/MEChargedCurrentDIS.cc
@@ -1,301 +1,304 @@
// -*- C++ -*-
//
// This is the implementation of the non-inlined, non-templated member
// functions of the MEChargedCurrentDIS class.
//
#include "MEChargedCurrentDIS.h"
#include "ThePEG/Utilities/SimplePhaseSpace.h"
#include "ThePEG/Interface/ClassDocumentation.h"
#include "ThePEG/Persistency/PersistentOStream.h"
#include "ThePEG/Persistency/PersistentIStream.h"
#include "ThePEG/PDT/EnumParticles.h"
#include "ThePEG/MatrixElement/Tree2toNDiagram.h"
#include "ThePEG/Interface/Switch.h"
#include "ThePEG/Interface/Parameter.h"
#include "Herwig++/MatrixElement/HardVertex.h"
#include "ThePEG/Helicity/WaveFunction/VectorWaveFunction.h"
#include "Herwig++/Models/StandardModel/StandardModel.h"
#include "ThePEG/Cuts/Cuts.h"
#include "ThePEG/Handlers/StandardXComb.h"
#include "ThePEG/PDF/PolarizedBeamParticleData.h"
using namespace Herwig;
MEChargedCurrentDIS::MEChargedCurrentDIS()
: _maxflavour(5), _massopt(0) {
vector<unsigned int> mopt(2,1);
mopt[1] = _massopt;
massOption(mopt);
}
void MEChargedCurrentDIS::doinit() {
DISBase::doinit();
_wp = getParticleData(ThePEG::ParticleID::Wplus );
_wm = getParticleData(ThePEG::ParticleID::Wminus);
// cast the SM pointer to the Herwig SM pointer
tcHwSMPtr hwsm=ThePEG::dynamic_ptr_cast<tcHwSMPtr>(standardModel());
if(!hwsm) throw InitException()
<< "Must be the Herwig++ StandardModel class in "
<< "MEChargedCurrentDIS::doinit" << Exception::abortnow;
// vertices
_theFFWVertex = hwsm->vertexFFW();
}
void MEChargedCurrentDIS::getDiagrams() const {
// possible quarks
typedef std::vector<pair<long,long> > Pairvector;
Pairvector quarkpair;
quarkpair.reserve(6);
// don't even think of putting 'break' in here!
switch(_maxflavour) {
case 6:
quarkpair.push_back(make_pair(ParticleID::s, ParticleID::t));
quarkpair.push_back(make_pair(ParticleID::d, ParticleID::t));
quarkpair.push_back(make_pair(ParticleID::b, ParticleID::t));
case 5:
quarkpair.push_back(make_pair(ParticleID::b, ParticleID::c));
quarkpair.push_back(make_pair(ParticleID::b, ParticleID::u));
case 4:
quarkpair.push_back(make_pair(ParticleID::s, ParticleID::c));
quarkpair.push_back(make_pair(ParticleID::d, ParticleID::c));
case 3:
quarkpair.push_back(make_pair(ParticleID::s, ParticleID::u));
case 2:
quarkpair.push_back(make_pair(ParticleID::d, ParticleID::u));
default:
;
}
// create the diagrams
for(int il1=11;il1<=14;++il1) {
int il2 = il1%2==0 ? il1-1 : il1+1;
for(unsigned int iz=0;iz<2;++iz) {
tcPDPtr lepin = iz==1 ? getParticleData(il1) : getParticleData(-il1);
tcPDPtr lepout = iz==1 ? getParticleData(il2) : getParticleData(-il2);
tcPDPtr inter = lepin->iCharge()-lepout->iCharge()==3 ? _wp : _wm;
for(unsigned int iq=0;iq<quarkpair.size();++iq) {
tcPDPtr first = getParticleData(quarkpair[iq].first );
tcPDPtr second = getParticleData(quarkpair[iq].second);
if(inter==_wp) {
add(new_ptr((Tree2toNDiagram(3), lepin, inter, first ,
1, lepout, 2, second , -1)));
add(new_ptr((Tree2toNDiagram(3), lepin, inter, second->CC(),
1, lepout, 2, first->CC(), -2)));
}
else {
add(new_ptr((Tree2toNDiagram(3), lepin, inter, second ,
1, lepout, 2, first , -1)));
add(new_ptr((Tree2toNDiagram(3), lepin, inter, first->CC(),
1, lepout, 2, second->CC(), -2)));
}
}
}
}
}
unsigned int MEChargedCurrentDIS::orderInAlphaS() const {
return 0;
}
unsigned int MEChargedCurrentDIS::orderInAlphaEW() const {
return 2;
}
Selector<const ColourLines *>
MEChargedCurrentDIS::colourGeometries(tcDiagPtr diag) const {
static ColourLines c1("3 5");
static ColourLines c2("-3 -5");
Selector<const ColourLines *> sel;
if ( diag->id() == -1 )
sel.insert(1.0, &c1);
else
sel.insert(1.0, &c2);
return sel;
}
void MEChargedCurrentDIS::persistentOutput(PersistentOStream & os) const {
os << _theFFWVertex << _maxflavour << _wp << _wm << _massopt;
}
void MEChargedCurrentDIS::persistentInput(PersistentIStream & is, int) {
is >> _theFFWVertex >> _maxflavour >> _wp >> _wm >> _massopt;
}
ClassDescription<MEChargedCurrentDIS> MEChargedCurrentDIS::initMEChargedCurrentDIS;
// Definition of the static class description member.
void MEChargedCurrentDIS::Init() {
static ClassDocumentation<MEChargedCurrentDIS> documentation
("The MEChargedCurrentDIS class implements the matrix elements "
"for leading-order charged current deep inelastic scattering");
static Parameter<MEChargedCurrentDIS,unsigned int> interfaceMaxFlavour
( "MaxFlavour",
"The heaviest incoming quark flavour this matrix element is allowed to handle "
"(if applicable).",
&MEChargedCurrentDIS::_maxflavour, 5, 2, 6, false, false, true);
static Switch<MEChargedCurrentDIS,unsigned int> interfaceMassOption
("MassOption",
"Option for the treatment of the mass of the outgoing quarks",
&MEChargedCurrentDIS::_massopt, 0, false, false);
static SwitchOption interfaceMassOptionMassless
(interfaceMassOption,
"Massless",
"Treat the outgoing quarks as massless",
0);
static SwitchOption interfaceMassOptionMassive
(interfaceMassOption,
"Massive",
"Treat the outgoing quarks as massive",
1);
}
Selector<MEBase::DiagramIndex>
MEChargedCurrentDIS::diagrams(const DiagramVector & diags) const {
Selector<DiagramIndex> sel;
for ( DiagramIndex i = 0; i < diags.size(); ++i ) sel.insert(1., i);
return sel;
}
double MEChargedCurrentDIS::helicityME(vector<SpinorWaveFunction> & f1,
vector<SpinorWaveFunction> & f2,
vector<SpinorBarWaveFunction> & a1,
vector<SpinorBarWaveFunction> & a2,
bool lorder, bool qorder, bool calc) const {
// scale
Energy2 mb2(scale());
// matrix element to be stored
ProductionMatrixElement menew(PDT::Spin1Half,PDT::Spin1Half,
PDT::Spin1Half,PDT::Spin1Half);
// pick a W boson
tcPDPtr ipart = (mePartonData()[0]->iCharge()-mePartonData()[1]->iCharge())==3 ?
_wp : _wm;
// declare the variables we need
VectorWaveFunction inter;
double me(0.);
Complex diag;
// sum over helicities to get the matrix element
unsigned int hel[4];
unsigned int lhel1,lhel2,qhel1,qhel2;
for(lhel1=0;lhel1<2;++lhel1) {
for(lhel2=0;lhel2<2;++lhel2) {
// intermediate W
inter = _theFFWVertex->evaluate(mb2,3,ipart,f1[lhel1],a1[lhel2]);
for(qhel1=0;qhel1<2;++qhel1) {
for(qhel2=0;qhel2<2;++qhel2) {
hel[0] = lhel1;
hel[1] = qhel1;
hel[2] = lhel2;
hel[3] = qhel2;
if(!lorder) swap(hel[0],hel[2]);
if(!qorder) swap(hel[1],hel[3]);
diag = _theFFWVertex->evaluate(mb2,f2[qhel1],a2[qhel2],inter);
me += norm(diag);
menew(hel[0],hel[1],hel[2],hel[3]) = diag;
}
}
}
}
// spin and colour factor
me *= 0.25;
tcPolarizedBeamPDPtr beam[2] =
{dynamic_ptr_cast<tcPolarizedBeamPDPtr>(mePartonData()[0]),
dynamic_ptr_cast<tcPolarizedBeamPDPtr>(mePartonData()[1])};
if( beam[0] || beam[1] ) {
RhoDMatrix rho[2] = {beam[0] ? beam[0]->rhoMatrix() : RhoDMatrix(mePartonData()[0]->iSpin()),
beam[1] ? beam[1]->rhoMatrix() : RhoDMatrix(mePartonData()[1]->iSpin())};
me = menew.average(rho[0],rho[1]);
}
if(calc) _me.reset(menew);
return me;
}
double MEChargedCurrentDIS::me2() const {
vector<SpinorWaveFunction> f1,f2;
vector<SpinorBarWaveFunction> a1,a2;
bool lorder,qorder;
SpinorWaveFunction l1,q1;
SpinorBarWaveFunction l2,q2;
// lepton wave functions
if(mePartonData()[0]->id()>0) {
lorder=true;
l1 = SpinorWaveFunction (meMomenta()[0],mePartonData()[0],incoming);
l2 = SpinorBarWaveFunction(meMomenta()[2],mePartonData()[2],outgoing);
}
else {
lorder=false;
l1 = SpinorWaveFunction (meMomenta()[2],mePartonData()[2],outgoing);
l2 = SpinorBarWaveFunction(meMomenta()[0],mePartonData()[0],incoming);
}
// quark wave functions
if(mePartonData()[1]->id()>0) {
qorder = true;
q1 = SpinorWaveFunction (meMomenta()[1],mePartonData()[1],incoming);
q2 = SpinorBarWaveFunction(meMomenta()[3],mePartonData()[3],outgoing);
}
else {
qorder = false;
q1 = SpinorWaveFunction (meMomenta()[3],mePartonData()[3],outgoing);
q2 = SpinorBarWaveFunction(meMomenta()[1],mePartonData()[1],incoming);
}
// wavefunctions for various helicities
for(unsigned int ix=0;ix<2;++ix) {
l1.reset(ix); f1.push_back(l1);
l2.reset(ix); a1.push_back(l2);
q1.reset(ix); f2.push_back(q1);
q2.reset(ix); a2.push_back(q2);
}
return helicityME(f1,f2,a1,a2,lorder,qorder,false);
}
void MEChargedCurrentDIS::constructVertex(tSubProPtr sub) {
// extract the particles in the hard process
ParticleVector hard;
hard.push_back(sub->incoming().first);
hard.push_back(sub->incoming().second);
hard.push_back(sub->outgoing()[0]);
hard.push_back(sub->outgoing()[1]);
+ // sort out the ordering
unsigned int order[4]={0,1,2,3};
bool lorder(true),qorder(true);
+ if(abs(hard[0]->id())<6) swap(hard[0],hard[1]);
+ if(abs(hard[2]->id())<6) swap(hard[2],hard[3]);
if(hard[0]->id()<0) {
swap(order[0],order[2]);
lorder = false;
}
if(hard[1]->id()<0) {
swap(order[1],order[3]);
qorder = false;
}
vector<SpinorWaveFunction> f1,f2;
vector<SpinorBarWaveFunction> a1,a2;
- SpinorWaveFunction (f1,hard[order[0]],incoming,!lorder,true);
- SpinorWaveFunction (f2,hard[order[1]],incoming,!qorder,true);
- SpinorBarWaveFunction(a1,hard[order[2]],outgoing, lorder,true);
- SpinorBarWaveFunction(a2,hard[order[3]],outgoing, qorder,true);
+ SpinorWaveFunction (f1,hard[order[0]], lorder ? incoming : outgoing, !lorder,true);
+ SpinorWaveFunction (f2,hard[order[1]], qorder ? incoming : outgoing, !qorder,true);
+ SpinorBarWaveFunction(a1,hard[order[2]], lorder ? outgoing : incoming, lorder,true);
+ SpinorBarWaveFunction(a2,hard[order[3]], qorder ? outgoing : incoming, qorder,true);
helicityME(f1,f2,a1,a2,lorder,qorder,true);
// construct the vertex
HardVertexPtr hardvertex=new_ptr(HardVertex());
// set the matrix element for the vertex
hardvertex->ME(_me);
// set the pointers and to and from the vertex
for(unsigned int ix=0;ix<4;++ix) {
tSpinPtr spin = hard[ix]->spinInfo();
if(ix<2) {
tcPolarizedBeamPDPtr beam =
dynamic_ptr_cast<tcPolarizedBeamPDPtr>(hard[ix]->dataPtr());
if(beam) spin->rhoMatrix() = beam->rhoMatrix();
}
spin->productionVertex(hardvertex);
}
}
double MEChargedCurrentDIS::A(tcPDPtr lin, tcPDPtr,
tcPDPtr qin, tcPDPtr, Energy2) const {
double output = 2.;
if(qin->id()<0) output *= -1.;
if(lin->id()<0) output *= -1;
return output;
}
diff --git a/MatrixElement/DIS/MENeutralCurrentDIS.cc b/MatrixElement/DIS/MENeutralCurrentDIS.cc
--- a/MatrixElement/DIS/MENeutralCurrentDIS.cc
+++ b/MatrixElement/DIS/MENeutralCurrentDIS.cc
@@ -1,357 +1,360 @@
// -*- C++ -*-
//
// This is the implementation of the non-inlined, non-templated member
// functions of the MENeutralCurrentDIS class.
//
#include "MENeutralCurrentDIS.h"
#include "ThePEG/Utilities/SimplePhaseSpace.h"
#include "ThePEG/Interface/ClassDocumentation.h"
#include "ThePEG/Interface/Switch.h"
#include "ThePEG/Interface/Parameter.h"
#include "ThePEG/Persistency/PersistentOStream.h"
#include "ThePEG/Persistency/PersistentIStream.h"
#include "ThePEG/PDT/EnumParticles.h"
#include "ThePEG/MatrixElement/Tree2toNDiagram.h"
#include "Herwig++/MatrixElement/HardVertex.h"
#include "ThePEG/Helicity/WaveFunction/VectorWaveFunction.h"
#include "Herwig++/Models/StandardModel/StandardModel.h"
#include "ThePEG/Cuts/Cuts.h"
#include "ThePEG/Handlers/StandardXComb.h"
#include "ThePEG/PDF/PolarizedBeamParticleData.h"
using namespace Herwig;
MENeutralCurrentDIS::MENeutralCurrentDIS()
: _minflavour(1), _maxflavour(5), _gammaZ(0),
_sinW(0.), _cosW(0.), _mz2(ZERO) {
vector<unsigned int> mopt(2,0);
mopt[0] = 1;
massOption(mopt);
}
void MENeutralCurrentDIS::doinit() {
DISBase::doinit();
_z0 = getParticleData(ThePEG::ParticleID::Z0);
_gamma = getParticleData(ThePEG::ParticleID::gamma);
// cast the SM pointer to the Herwig SM pointer
tcHwSMPtr hwsm=ThePEG::dynamic_ptr_cast<tcHwSMPtr>(standardModel());
if(!hwsm) throw InitException()
<< "Must be the Herwig++ StandardModel class in "
<< "MENeutralCurrentDIS::doinit" << Exception::abortnow;
// vertices
_theFFZVertex = hwsm->vertexFFZ();
_theFFPVertex = hwsm->vertexFFP();
// electroweak parameters
_sinW = generator()->standardModel()->sin2ThetaW();
_cosW = sqrt(1.-_sinW);
_sinW = sqrt(_sinW);
_mz2 = sqr(_z0->mass());
}
void MENeutralCurrentDIS::getDiagrams() const {
// which intermediates to include
bool gamma = _gammaZ==0 || _gammaZ==1;
bool Z0 = _gammaZ==0 || _gammaZ==2;
// create the diagrams
for(int ix=11;ix<=14;++ix) {
for(unsigned int iz=0;iz<2;++iz) {
tPDPtr lep = getParticleData(ix);
if(iz==1) lep = lep->CC();
for(int iy=_minflavour;iy<=_maxflavour;++iy) {
tPDPtr quark = getParticleData(iy);
// lepton quark scattering via gamma and Z
if(gamma) add(new_ptr((Tree2toNDiagram(3), lep, _gamma, quark,
1, lep, 2, quark, -1)));
if(Z0) add(new_ptr((Tree2toNDiagram(3), lep, _z0 , quark,
1, lep, 2, quark, -2)));
// lepton antiquark scattering via gamma and Z
quark = quark->CC();
if(gamma) add(new_ptr((Tree2toNDiagram(3), lep, _gamma, quark,
1, lep, 2, quark, -3)));
if(Z0) add(new_ptr((Tree2toNDiagram(3), lep, _z0 , quark,
1, lep, 2, quark, -4)));
}
}
}
}
unsigned int MENeutralCurrentDIS::orderInAlphaS() const {
return 0;
}
unsigned int MENeutralCurrentDIS::orderInAlphaEW() const {
return 2;
}
Selector<const ColourLines *>
MENeutralCurrentDIS::colourGeometries(tcDiagPtr diag) const {
static ColourLines c1("3 5");
static ColourLines c2("-3 -5");
Selector<const ColourLines *> sel;
if ( diag->id() == -1 || diag->id() == -2 )
sel.insert(1.0, &c1);
else
sel.insert(1.0, &c2);
return sel;
}
void MENeutralCurrentDIS::persistentOutput(PersistentOStream & os) const {
os << _minflavour << _maxflavour << _gammaZ << _theFFZVertex << _theFFPVertex
<< _gamma << _z0 << _sinW << _cosW << ounit(_mz2,GeV2);
}
void MENeutralCurrentDIS::persistentInput(PersistentIStream & is, int) {
is >> _minflavour >> _maxflavour >> _gammaZ >> _theFFZVertex >> _theFFPVertex
>> _gamma >> _z0 >> _sinW >> _cosW >> iunit(_mz2,GeV2) ;
}
ClassDescription<MENeutralCurrentDIS> MENeutralCurrentDIS::initMENeutralCurrentDIS;
// Definition of the static class description member.
void MENeutralCurrentDIS::Init() {
static ClassDocumentation<MENeutralCurrentDIS> documentation
("The MENeutralCurrentDIS class implements the matrix elements for leading-order "
"neutral current deep inelastic scattering.");
static Parameter<MENeutralCurrentDIS,int> interfaceMaxFlavour
("MaxFlavour",
"The highest incoming quark flavour this matrix element is allowed to handle",
&MENeutralCurrentDIS::_maxflavour, 5, 1, 5,
false, false, Interface::limited);
static Parameter<MENeutralCurrentDIS,int> interfaceMinFlavour
("MinFlavour",
"The lightest incoming quark flavour this matrix element is allowed to handle",
&MENeutralCurrentDIS::_minflavour, 1, 1, 5,
false, false, Interface::limited);
static Switch<MENeutralCurrentDIS,unsigned int> interfaceGammaZ
("GammaZ",
"Which terms to include",
&MENeutralCurrentDIS::_gammaZ, 0, false, false);
static SwitchOption interfaceGammaZAll
(interfaceGammaZ,
"All",
"Include both gamma and Z terms",
0);
static SwitchOption interfaceGammaZGamma
(interfaceGammaZ,
"Gamma",
"Only include the photon",
1);
static SwitchOption interfaceGammaZZ
(interfaceGammaZ,
"Z",
"Only include the Z",
2);
}
Selector<MEBase::DiagramIndex>
MENeutralCurrentDIS::diagrams(const DiagramVector & diags) const {
Selector<DiagramIndex> sel;
for ( DiagramIndex i = 0; i < diags.size(); ++i ) {
if ( diags[i]->id() == -1 || diags[i]->id() == -3 ) sel.insert(meInfo()[0], i);
else if ( diags[i]->id() == -2 || diags[i]->id() == -4 ) sel.insert(meInfo()[1], i);
}
return sel;
}
double MENeutralCurrentDIS::helicityME(vector<SpinorWaveFunction> & f1,
vector<SpinorWaveFunction> & f2,
vector<SpinorBarWaveFunction> & a1,
vector<SpinorBarWaveFunction> & a2,
bool lorder, bool qorder,
bool calc) const {
// scale
Energy2 mb2(scale());
// matrix element to be stored
ProductionMatrixElement menew (PDT::Spin1Half,PDT::Spin1Half,
PDT::Spin1Half,PDT::Spin1Half);
ProductionMatrixElement gamma (PDT::Spin1Half,PDT::Spin1Half,
PDT::Spin1Half,PDT::Spin1Half);
ProductionMatrixElement Zboson(PDT::Spin1Half,PDT::Spin1Half,
PDT::Spin1Half,PDT::Spin1Half);
// which intermediates to include
bool gam = _gammaZ==0 || _gammaZ==1;
bool Z0 = _gammaZ==0 || _gammaZ==2;
// declare the variables we need
VectorWaveFunction inter[2];
double me[3]={0.,0.,0.};
Complex diag1,diag2;
// sum over helicities to get the matrix element
unsigned int hel[4];
unsigned int lhel1,lhel2,qhel1,qhel2;
for(lhel1=0;lhel1<2;++lhel1) {
for(lhel2=0;lhel2<2;++lhel2) {
// intermediate for photon
if(gam) inter[0]=_theFFPVertex->evaluate(mb2,1,_gamma,f1[lhel1],a1[lhel2]);
// intermediate for Z
if(Z0) inter[1]=_theFFZVertex->evaluate(mb2,1,_z0 ,f1[lhel1],a1[lhel2]);
for(qhel1=0;qhel1<2;++qhel1) {
for(qhel2=0;qhel2<2;++qhel2) {
hel[0] = lhel1;
hel[1] = qhel1;
hel[2] = lhel2;
hel[3] = qhel2;
if(!lorder) swap(hel[0],hel[2]);
if(!qorder) swap(hel[1],hel[3]);
// first the photon exchange diagram
diag1 = gam ?
_theFFPVertex->evaluate(mb2,f2[qhel1],a2[qhel2],inter[0]) : 0.;
// then the Z exchange diagram
diag2 = Z0 ?
_theFFZVertex->evaluate(mb2,f2[qhel1],a2[qhel2],inter[1]) : 0.;
// add up squares of individual terms
me[1] += norm(diag1);
gamma (hel[0],hel[1],hel[2],hel[3]) = diag1;
me[2] += norm(diag2);
Zboson(hel[0],hel[1],hel[2],hel[3]) = diag2;
// the full thing including interference
diag1 += diag2;
me[0] += norm(diag1);
menew(hel[0],hel[1],hel[2],hel[3]) = diag1;
}
}
}
}
// spin and colour factor
double colspin = 0.25;
// results
for(int ix=0;ix<3;++ix) me[ix] *= colspin;
tcPolarizedBeamPDPtr beam[2] =
{dynamic_ptr_cast<tcPolarizedBeamPDPtr>(mePartonData()[0]),
dynamic_ptr_cast<tcPolarizedBeamPDPtr>(mePartonData()[1])};
if( beam[0] || beam[1] ) {
RhoDMatrix rho[2] = {beam[0] ? beam[0]->rhoMatrix() : RhoDMatrix(mePartonData()[0]->iSpin()),
beam[1] ? beam[1]->rhoMatrix() : RhoDMatrix(mePartonData()[1]->iSpin())};
me[0] = menew .average(rho[0],rho[1]);
me[1] = gamma .average(rho[0],rho[1]);
me[2] = Zboson.average(rho[0],rho[1]);
}
DVector save;
save.push_back(me[1]);
save.push_back(me[2]);
meInfo(save);
if(calc) _me.reset(menew);
// analytic expression for testing
// double test = 8.*sqr(4.*Constants::pi*generator()->standardModel()->alphaEM(mb2))*
// sqr(double(mePartonData()[1]->iCharge())/3.)/sqr(tHat())
// *(sqr(sHat())+sqr(uHat())+4.*sqr(mePartonData()[0]->mass())*tHat())/4.;
// cerr << "testing me " << me[0]/test << "\n";
return me[0];
}
double MENeutralCurrentDIS::me2() const {
vector<SpinorWaveFunction> f1,f2;
vector<SpinorBarWaveFunction> a1,a2;
bool lorder,qorder;
SpinorWaveFunction l1,q1;
SpinorBarWaveFunction l2,q2;
// lepton wave functions
if(mePartonData()[0]->id()>0) {
lorder=true;
l1 = SpinorWaveFunction (meMomenta()[0],mePartonData()[0],incoming);
l2 = SpinorBarWaveFunction(meMomenta()[2],mePartonData()[2],outgoing);
}
else {
lorder=false;
l1 = SpinorWaveFunction (meMomenta()[2],mePartonData()[2],outgoing);
l2 = SpinorBarWaveFunction(meMomenta()[0],mePartonData()[0],incoming);
}
// quark wave functions
if(mePartonData()[1]->id()>0) {
qorder = true;
q1 = SpinorWaveFunction (meMomenta()[1],mePartonData()[1],incoming);
q2 = SpinorBarWaveFunction(meMomenta()[3],mePartonData()[3],outgoing);
}
else {
qorder = false;
q1 = SpinorWaveFunction (meMomenta()[3],mePartonData()[3],outgoing);
q2 = SpinorBarWaveFunction(meMomenta()[1],mePartonData()[1],incoming);
}
// wavefunctions for various helicities
for(unsigned int ix=0;ix<2;++ix) {
l1.reset(ix); f1.push_back(l1);
l2.reset(ix); a1.push_back(l2);
q1.reset(ix); f2.push_back(q1);
q2.reset(ix); a2.push_back(q2);
}
return helicityME(f1,f2,a1,a2,lorder,qorder,false);
}
void MENeutralCurrentDIS::constructVertex(tSubProPtr sub) {
// extract the particles in the hard process
ParticleVector hard;
hard.push_back(sub->incoming().first);
hard.push_back(sub->incoming().second);
hard.push_back(sub->outgoing()[0]);
hard.push_back(sub->outgoing()[1]);
+ // sort out the ordering
unsigned int order[4]={0,1,2,3};
bool lorder(true),qorder(true);
+ if(abs(hard[0]->id())<6) swap(hard[0],hard[1]);
+ if(abs(hard[2]->id())<6) swap(hard[2],hard[3]);
if(hard[0]->id()<0) {
swap(order[0],order[2]);
lorder = false;
}
if(hard[1]->id()<0) {
swap(order[1],order[3]);
qorder = false;
}
vector<SpinorWaveFunction> f1,f2;
vector<SpinorBarWaveFunction> a1,a2;
- SpinorWaveFunction (f1,hard[order[0]],incoming,!lorder,true);
- SpinorWaveFunction (f2,hard[order[1]],incoming,!qorder,true);
- SpinorBarWaveFunction(a1,hard[order[2]],outgoing, lorder,true);
- SpinorBarWaveFunction(a2,hard[order[3]],outgoing, qorder,true);
+ SpinorWaveFunction (f1,hard[order[0]], lorder ? incoming : outgoing, !lorder,true);
+ SpinorWaveFunction (f2,hard[order[1]], qorder ? incoming : outgoing, !qorder,true);
+ SpinorBarWaveFunction(a1,hard[order[2]], lorder ? outgoing : incoming, lorder,true);
+ SpinorBarWaveFunction(a2,hard[order[3]], qorder ? outgoing : incoming, qorder,true);
helicityME(f1,f2,a1,a2,lorder,qorder,true);
// construct the vertex
HardVertexPtr hardvertex=new_ptr(HardVertex());
// set the matrix element for the vertex
hardvertex->ME(_me);
// set the pointers and to and from the vertex
for(unsigned int ix=0;ix<4;++ix) {
tSpinPtr spin = hard[ix]->spinInfo();
if(ix<2) {
tcPolarizedBeamPDPtr beam =
dynamic_ptr_cast<tcPolarizedBeamPDPtr>(hard[ix]->dataPtr());
if(beam) spin->rhoMatrix() = beam->rhoMatrix();
}
spin->productionVertex(hardvertex);
}
}
double MENeutralCurrentDIS::A(tcPDPtr lin, tcPDPtr,
tcPDPtr qin, tcPDPtr, Energy2 q2) const {
// photon only
if(_gammaZ==1) return 0.;
// everything else
double r = _gammaZ==0 || _gammaZ==2 ? double(q2/(q2+_mz2)) : 0.;
double eL,eQ,cvL,caL,cvQ,caQ;;
if(abs(lin->id())%2==0) {
eL = _gammaZ==0 ? generator()->standardModel()->enu() : 0.;
cvL = 0.25*generator()->standardModel()->vnu();
caL = 0.25*generator()->standardModel()->anu();
}
else {
eL = _gammaZ==0 ? generator()->standardModel()->ee() : 0.;
cvL = 0.25*generator()->standardModel()->ve();
caL = 0.25*generator()->standardModel()->ae();
}
if(abs(qin->id())%2==0) {
eQ = _gammaZ==0 ? generator()->standardModel()->eu() : 0.;
cvQ = 0.25*generator()->standardModel()->vu();
caQ = 0.25*generator()->standardModel()->au();
}
else {
eQ = _gammaZ==0 ? generator()->standardModel()->ed() : 0.;
cvQ = 0.25*generator()->standardModel()->vd();
caQ = 0.25*generator()->standardModel()->ad();
}
double output = 4.*r*caL*caQ*(eL*eQ+2.*r*cvL*cvQ/sqr(_sinW*_cosW))
/sqr(_sinW*_cosW)/(sqr(eL*eQ)+2.*eL*eQ*r/sqr(_cosW*_sinW)*cvL*cvQ
+sqr(r/sqr(_cosW*_sinW))*(sqr(cvL)+sqr(caL))*(sqr(cvQ)+sqr(caQ)));
if(qin->id()<0) output *= -1.;
if(lin->id()<0) output *= -1.;
return output;
}

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