G4INCLNKElasticChannel.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 "G4INCLNKElasticChannel.hh"
#include "G4INCLKinematicsUtils.hh"
#include "G4INCLBinaryCollisionAvatar.hh"
#include "G4INCLRandom.hh"
#include "G4INCLGlobals.hh"
#include "G4INCLLogger.hh"
#include <algorithm>
#include "G4INCLPhaseSpaceGenerator.hh"

namespace G4INCL {
  
  NKElasticChannel::NKElasticChannel(Particle *p1, Particle *p2)
    : particle1(p1), particle2(p2)
    {}
  
  NKElasticChannel::~NKElasticChannel(){}
  
  void NKElasticChannel::fillFinalState(FinalState *fs) {
    
    Particle *nucleon;
    Particle *kaon;
    
    if(particle1->isNucleon()){
      nucleon = particle1;
      kaon = particle2;
    }
    else{
      nucleon = particle2;
      kaon = particle1;
    }
    
    const G4double norm = KinematicsUtils::momentumInCM(nucleon, kaon);
    
    ThreeVector mom_kaon;
    
//    const G4double pLab = KinematicsUtils::momentumInLab(kaon,nucleon);
    
/*    if(pLab==0) mom_kaon = Random::normVector();
    else{
      const G4double x = kaon->getMomentum().getX();
      const G4double y = kaon->getMomentum().getY();
      const G4double z = kaon->getMomentum().getZ();
      
      const G4double r = std::sqrt(x*x+y*y+z*z);
      const G4double rho = std::sqrt(x*x+y*y);
      
      const G4double b = 12. * pLab/2375.; // correspond to the forward slope description at 2375 MeV/c in K- p elastic
      const G4double cos_theta = std::log(Random::shoot()*(std::exp(b)-std::exp(-b))+std::exp(-b))/b;
      const G4double sin_theta = std::sqrt(1-cos_theta*cos_theta);
      
      const G4double cos_phi = std::cos(Random::shoot()*Math::twoPi);
      const G4double sin_phi = std::sqrt(1-cos_phi*cos_phi);
      
      if(rho == 0) mom_kaon = ThreeVector(sin_theta*cos_phi,sin_theta*sin_phi,cos_theta);
      // Rotation in the direction of the incident kaon
      const G4double px = x/r*cos_theta - y/rho*sin_theta*cos_phi + z/r*x/rho*sin_theta*sin_phi;
      const G4double py = y/r*cos_theta + x/rho*sin_theta*cos_phi + z/r*y/rho*sin_theta*sin_phi;
      const G4double pz = z/r*cos_theta - rho/r*sin_theta*sin_phi;
      
      mom_kaon = ThreeVector(px,py,pz);
    }*/
    
    mom_kaon = Random::normVector();
    
    kaon->setMomentum(mom_kaon*norm);
    nucleon->setMomentum(-mom_kaon*norm);
    
    kaon->adjustEnergyFromMomentum();
    nucleon->adjustEnergyFromMomentum();
    
    fs->addModifiedParticle(nucleon);
    fs->addModifiedParticle(kaon);
        
  }
}