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geant4/source/processes/hadronic/models/lepto_nuclear/src/G4NeutrinoElectronCcModel.cc
T
Gabriele Cosmo 6aa23be517 Import Geant4 10.5.0.beta source tree
2018-06-29 10:58:11 +02:00

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//
// ********************************************************************
// * License and Disclaimer *
// * *
// * The Geant4 software is copyright of the Copyright Holders of *
// * the Geant4 Collaboration. It is provided under the terms and *
// * conditions of the Geant4 Software License, included in the file *
// * LICENSE and available at http://cern.ch/geant4/license . These *
// * include a list of copyright holders. *
// * *
// * Neither the authors of this software system, nor their employing *
// * institutes,nor the agencies providing financial support for this *
// * work make any representation or warranty, express or implied, *
// * regarding this software system or assume any liability for its *
// * use. Please see the license in the file LICENSE and URL above *
// * for the full disclaimer and the limitation of liability. *
// * *
// * This code implementation is the result of the scientific and *
// * technical work of the GEANT4 collaboration. *
// * By using, copying, modifying or distributing the software (or *
// * any work based on the software) you agree to acknowledge its *
// * use in resulting scientific publications, and indicate your *
// * acceptance of all terms of the Geant4 Software license. *
// ********************************************************************
//
// $Id: G4NeutrinoElectronCcModel.cc 91806 2015-08-06 12:20:45Z gcosmo $
//
// Geant4 Header : G4NeutrinoElectronCcModel
//
// Author : V.Grichine 26.4.17
//
#include "G4NeutrinoElectronCcModel.hh"
#include "G4SystemOfUnits.hh"
#include "G4ParticleTable.hh"
#include "G4ParticleDefinition.hh"
#include "G4IonTable.hh"
#include "Randomize.hh"
#include "G4NeutrinoE.hh"
#include "G4AntiNeutrinoE.hh"
#include "G4MuonMinus.hh"
#include "G4TauMinus.hh"
using namespace std;
using namespace CLHEP;
G4NeutrinoElectronCcModel::G4NeutrinoElectronCcModel(const G4String& name)
: G4HadronicInteraction(name)
{
SetMinEnergy( 0.0*GeV );
SetMaxEnergy( 100.*TeV );
SetMinEnergy(1.e-6*eV);
theNeutrinoE = G4NeutrinoE::NeutrinoE();
theAntiNeutrinoE = G4AntiNeutrinoE::AntiNeutrinoE();
theMuonMinus = G4MuonMinus::MuonMinus();
theTauMinus = G4TauMinus::TauMinus();
// PDG2016: sin^2 theta Weinberg
fSin2tW = 0.23129; // 0.2312;
fCutEnergy = 0.; // default value
}
G4NeutrinoElectronCcModel::~G4NeutrinoElectronCcModel()
{}
void G4NeutrinoElectronCcModel::ModelDescription(std::ostream& outFile) const
{
outFile << "G4NeutrinoElectronCcModel is a neutrino-electron (neutral current) elastic scattering\n"
<< "model which uses the standard model \n"
<< "transfer parameterization. The model is fully relativistic\n";
}
/////////////////////////////////////////////////////////
G4bool G4NeutrinoElectronCcModel::IsApplicable(const G4HadProjectile & aPart,
G4Nucleus & targetNucleus)
{
G4bool result = false;
G4String pName = aPart.GetDefinition()->GetParticleName();
G4double minEnergy = 0., energy = aPart.GetTotalEnergy();
G4double fmass, emass = electron_mass_c2;
if( pName == "nu_mu" || pName == "anti_nu_mu" ) fmass = theMuonMinus->GetPDGMass();
else if( pName == "nu_tau" || pName == "anti_nu_tau" ) fmass = theTauMinus->GetPDGMass();
else fmass = emass;
minEnergy = (fmass-emass)*(fmass+emass)/emass;
SetMinEnergy( minEnergy );
if( ( pName == "nu_mu" || pName == "anti_nu_mu" ||
pName == "nu_tau" || pName == "anti_nu_tau" ) &&
energy > minEnergy )
{
result = true;
}
G4int Z = targetNucleus.GetZ_asInt();
Z *= 1;
return result;
}
////////////////////////////////////////////////
//
//
G4HadFinalState* G4NeutrinoElectronCcModel::ApplyYourself(
const G4HadProjectile& aTrack, G4Nucleus& targetNucleus)
{
theParticleChange.Clear();
const G4HadProjectile* aParticle = &aTrack;
G4double energy = aParticle->GetTotalEnergy();
G4String pName = aParticle->GetDefinition()->GetParticleName();
G4double minEnergy(0.), fmass(0.), emass = electron_mass_c2;
if( pName == "nu_mu" || pName == "anti_nu_mu" ) fmass = theMuonMinus->GetPDGMass();
else if( pName == "nu_tau" || pName == "anti_nu_tau" ) fmass = theTauMinus->GetPDGMass();
else fmass = emass;
minEnergy = (fmass-emass)*(fmass+emass)/emass;
if( energy <= minEnergy )
{
theParticleChange.SetEnergyChange(energy);
theParticleChange.SetMomentumChange(aTrack.Get4Momentum().vect().unit());
return &theParticleChange;
}
G4double massf(0.), massf2(0.); // , emass = electron_mass_c2;
G4double sTot = 2.*energy*emass + emass*emass;
G4LorentzVector lvp1 = aParticle->Get4Momentum();
G4LorentzVector lvt1(0.,0.,0.,electron_mass_c2);
G4LorentzVector lvsum = lvp1+lvt1;
G4ThreeVector bst = lvsum.boostVector();
// sample and make final state in CMS frame
G4double cost = SampleCosCMS( aParticle );
G4double sint = std::sqrt( (1.0 - cost)*(1.0 + cost) );
G4double phi = G4UniformRand()*CLHEP::twopi;
G4ThreeVector eP( sint*std::cos(phi), sint*std::sin(phi), cost );
if( pName == "nu_mu" || pName == "anti_nu_mu" ) massf = theMuonMinus->GetPDGMass();
else if( pName == "nu_tau" || pName == "anti_nu_tau") massf = theTauMinus->GetPDGMass();
massf2 = massf*massf;
G4double epf = 0.5*(sTot - massf2)/sqrt(sTot);
// G4double etf = epf*(sTot + massf2)/(sTot - massf2);
eP *= epf;
G4LorentzVector lvp2( eP, epf );
lvp2.boost(bst); // back to lab frame
G4LorentzVector lvt2 = lvsum - lvp2; // ?
G4DynamicParticle* aNu = nullptr;
G4DynamicParticle* aLept = nullptr;
if( pName == "nu_mu" || pName == "nu_tau")
{
aNu = new G4DynamicParticle( theNeutrinoE, lvp2 );
}
else if( pName == "anti_nu_mu" || pName == "anti_nu_tau")
{
aNu = new G4DynamicParticle( theAntiNeutrinoE, lvp2 );
}
if( pName == "nu_mu" || pName == "anti_nu_mu")
{
aLept = new G4DynamicParticle( theMuonMinus, lvt2 );
}
else if( pName == "nu_tau" || pName == "anti_nu_tau")
{
aLept = new G4DynamicParticle( theTauMinus, lvt2 );
}
if(aNu) { theParticleChange.AddSecondary( aNu ); }
if(aLept) { theParticleChange.AddSecondary( aLept ); }
G4int Z = targetNucleus.GetZ_asInt();
Z *= 1;
return &theParticleChange;
}
//////////////////////////////////////////////////////
//
// sample recoil electron energy in lab frame
G4double G4NeutrinoElectronCcModel::SampleCosCMS(const G4HadProjectile* aParticle)
{
G4double result = 0., cofL, cofR, cofLR, massf2, sTot, emass = electron_mass_c2, emass2;
G4double energy = aParticle->GetTotalEnergy();
if( energy == 0.) return result; // vmg: < th?? as in xsc
G4String pName = aParticle->GetDefinition()->GetParticleName();
if( pName == "nu_mu" || pName == "nu_tau")
{
return 2.*G4UniformRand()-1.; // uniform scattering cos in CMS
}
else if( pName == "anti_nu_mu" || pName == "anti_nu_tau")
{
emass2 = emass*emass;
sTot = 2.*energy*emass + emass2;
cofL = (sTot-emass2)/(sTot+emass2);
if(pName == "anti_nu_mu") massf2 = theMuonMinus->GetPDGMass()*theMuonMinus->GetPDGMass();
else massf2 = theTauMinus->GetPDGMass()*theTauMinus->GetPDGMass();
cofR = (sTot-massf2)/(sTot+massf2);
cofLR = cofL*cofR/3.;
// cofs of cos 3rd equation
G4double a = cofLR;
G4double b = 0.5*(cofR+cofL);
G4double c = 1.;
G4double d = -G4UniformRand()*2.*(1.+ cofLR);
d += c - b + a;
// G4cout<<a<<" "<<b<<" "<<c<<" "<<d<<G4endl<<G4endl;
// cofs of the incomplete 3rd equation
G4double p = c/a;
p -= b*b/a/a/3.;
G4double q = d/a;
q -= b*c/a/a/3.;
q += 2*b*b*b/a/a/a/27.;
// cofs for the incomplete colutions
G4double D = p*p*p/3./3./3.;
D += q*q/2./2.;
// G4cout<<"D = "<<D<<G4endl;
if(D < 0.) D = -D;
// G4complex A1 = G4complex(- q/2., std::sqrt(-D) );
// G4complex A = std::pow(A1,1./3.);
// G4complex B1 = G4complex(- q/2., -std::sqrt(-D) );
// G4complex B = std::pow(B1,1./3.);
G4double A, B;
G4double A1 = - q/2. + std::sqrt(D);
if (A1 < 0.) A1 = -A1;
A = std::pow(A1,1./3.);
if (A1 < 0.) A = -A;
G4double B1 = - q/2. - std::sqrt(D);
// G4double B = std::pow(-B1,1./3.);
if(B1 < 0.) B1 = -B1;
B = std::pow(B1,1./3.);
if(B1 < 0.) B = -B;
// G4cout<<"A1 = "<<A1<<"; A = "<<A<<"; B1 = "<<B1<<"; B = "<<B<<G4endl;
// roots of the incomplete 3rd equation
G4complex y1 = A + B;
// G4complex y2 = -0.5*(A + B) + 0.5*std::sqrt(3.)*(A - B)*G4complex(0.,1.);
// G4complex y3 = -0.5*(A + B) - 0.5*std::sqrt(3.)*(A - B)*G4complex(0.,1.);
G4complex x1 = y1 - b/a/3.;
// G4complex x2 = y2 - b/a/3.;
// G4complex x3 = y3 - b/a/3.;
// G4cout<<"re_x1 = "<<real(x1)<<" + i*"<<imag(x1)<<G4endl;
// G4cout<<"re_x1 = "<<real(x1)<<"; re_x2 = "<<real(x2)<<"; re_x3 = "<<real(x3)<<G4endl;
// G4cout<<"im_x1 = "<<imag(x1)<<"; im_x2 = "<<imag(x2)<<"; im_x3 = "<<imag(x3)<<G4endl<<G4endl;
result = real(x1);
}
else
{
return result;
}
return result;
}
//
//
///////////////////////////
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