G4INCLNNbarElasticChannel.cc

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//
// INCL++ intra-nuclear cascade model
// Alain Boudard, CEA-Saclay, France
// Joseph Cugnon, University of Liege, Belgium
// Jean-Christophe David, CEA-Saclay, France
// Pekka Kaitaniemi, CEA-Saclay, France, and Helsinki Institute of Physics, Finland
// Sylvie Leray, CEA-Saclay, France
// Davide Mancusi, CEA-Saclay, France
//
#define INCLXX_IN_GEANT4_MODE 1
 
#include "globals.hh"
 
#include "G4INCLNNbarElasticChannel.hh"
#include "G4INCLKinematicsUtils.hh"
#include "G4INCLBinaryCollisionAvatar.hh"
#include "G4INCLRandom.hh"
#include "G4INCLGlobals.hh"
#include "G4INCLLogger.hh"
#include <algorithm>
#include "G4INCLPhaseSpaceGenerator.hh"
 
namespace G4INCL {
    
    NNbarElasticChannel::NNbarElasticChannel(Particle *p1, Particle *p2)
        : particle1(p1), particle2(p2)
        {}
    
    NNbarElasticChannel::~NNbarElasticChannel(){}
    
    void NNbarElasticChannel::fillFinalState(FinalState *fs) {
 
        //brief ppbar
        // p pbar -> p pbar (BFMM 2)
        //
        //brief npbar
        // n pbar -> n pbar (BFMM 472)
        //
        //brief nnbar
        // n nbar -> n nbar (same as BFMM 2)
        //
        //brief pnbar 
        // p nbar -> p nbar (same as BFMM 472)
        //
        // 
 
        
 
        Particle *nucleon;
        Particle *antinucleon;
        
        if(particle1->isNucleon()){
            nucleon = particle1;
            antinucleon = particle2;
        }
        else{
            nucleon = particle2;
            antinucleon = particle1;
        }
        
        const G4double sqrtS = KinematicsUtils::totalEnergyInCM(nucleon, antinucleon);
        
        G4double mn=nucleon->getMass();
        G4double my=antinucleon->getMass();
        
        G4double ey=(sqrtS*sqrtS+my*my-mn*mn)/(2*sqrtS);
        G4double en=std::sqrt(ey*ey-my*my+mn*mn);
        nucleon->setEnergy(en);
        antinucleon->setEnergy(ey);
        G4double py=std::sqrt(ey*ey-my*my);
        
        ThreeVector mom_antinucleon = Random::normVector(py);
 
        antinucleon->setMomentum(mom_antinucleon);
        nucleon->setMomentum(-mom_antinucleon);
        
        fs->addModifiedParticle(nucleon);
        fs->addModifiedParticle(antinucleon);
    }
}