G4INCLOmegaNToPiNChannel.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 "G4INCLOmegaNToPiNChannel.hh"
#include "G4INCLKinematicsUtils.hh"
#include "G4INCLBinaryCollisionAvatar.hh"
#include "G4INCLRandom.hh"
#include "G4INCLGlobals.hh"
#include "G4INCLLogger.hh"

namespace G4INCL {

    OmegaNToPiNChannel::OmegaNToPiNChannel(Particle *p1, Particle *p2)
    : particle1(p1), particle2(p2)
    {

    }

    OmegaNToPiNChannel::~OmegaNToPiNChannel(){

    }

    void OmegaNToPiNChannel::fillFinalState(FinalState *fs) {
        Particle * nucleon;
        Particle * omega;
        if(particle1->isNucleon()) {
            nucleon = particle1;
            omega = particle2;
        } else {
            nucleon = particle2;
            omega = particle1;
        }

        const G4double r2 = Random::shoot();
        if (nucleon->getType() == Neutron) {
            if (r2*3. < 2.) {
                nucleon->setType(Proton);
                omega->setType(PiMinus);
            }
            else {
                nucleon->setType(Neutron);
                omega->setType(PiZero);
            }
        }
        else {
            if (r2*3. < 2.) {
                nucleon->setType(Neutron);
                omega->setType(PiPlus);
            }
            else {
                nucleon->setType(Proton);
                omega->setType(PiZero);
            }
        }
        
        G4double sh=nucleon->getEnergy()+omega->getEnergy();
        G4double mn=nucleon->getMass();
        G4double me=omega->getMass();
        G4double en=(sh*sh+mn*mn-me*me)/(2*sh);
        nucleon->setEnergy(en);
        G4double ee=std::sqrt(en*en-mn*mn+me*me);
        omega->setEnergy(ee);
        G4double pn=std::sqrt(en*en-mn*mn);
/*// test isotropy
        const G4double pi=std::acos(-1.0);      
        G4double x1;
        G4double u1;
        G4double fteta;
        G4double teta;
        G4double fi;

        G4int passe1=0;
        while (passe1==0) {
            // Sample x from 0 to pi/2
            x1=(pi/2.)*Random::shoot();
            // Sample u from 0 to 1
            u1=Random::shoot();
            fteta=std::sin(x1);
            // The condition
            if (u1 < fteta) {
                teta=x1;
                passe1=1;
                if (Random::shoot() < 0.5) {
                    teta=pi-teta;
                }
            }
        }
        fi=(2.0*pi)*Random::shoot();
        
// end test     
        ThreeVector mom_nucleon(
                                pn*std::sin(teta)*std::cos(fi),
                                pn*std::sin(teta)*std::sin(fi),
                                pn*std::cos(teta)
                                );
        if (Random::shoot() < 0.5) {
            nucleon->setMomentum(mom_nucleon);
            omega->setMomentum(-mom_nucleon);
        }
        else {
            omega->setMomentum(mom_nucleon);
            nucleon->setMomentum(-mom_nucleon);
        }
*/
        ThreeVector mom_nucleon = Random::normVector(pn);
        
        nucleon->setMomentum(mom_nucleon);
        omega->setMomentum(-mom_nucleon);
        
        fs->addModifiedParticle(nucleon);
        fs->addModifiedParticle(omega);
    }

}