G4HESigmaZeroInelastic.cc

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// $Id$

// G4 Process: Gheisha High Energy Collision model.
// This includes the high energy cascading model, the two-body-resonance model
// and the low energy two-body model. Not included are the low energy stuff
// like nuclear reactions, nuclear fission without any cascading and all
// processes for particles at rest.  
// First work done by J.L.Chuma and F.W.Jones, TRIUMF, June 96.  
// H. Fesefeldt, RWTH-Aachen, 23-October-1996
 
#include "G4HESigmaZeroInelastic.hh"
#include "globals.hh"
#include "G4ios.hh"
#include "G4Gamma.hh"

void G4HESigmaZeroInelastic::ModelDescription(std::ostream& outFile) const
{
  outFile << "G4HESigmaZeroInelastic is one of the High Energy\n"
          << "Parameterized (HEP) models used to implement inelastic\n"
          << "Sigma0 scattering from nuclei.  It is a re-engineered\n"
          << "version of the GHEISHA code of H. Fesefeldt.  It divides the\n"
          << "initial collision products into backward- and forward-going\n"
          << "clusters which are then decayed into final state hadrons.\n"
          << "The model does not conserve energy on an event-by-event\n"
          << "basis.  It may be applied to Sigma0 with initial energies\n"
          << "above 20 GeV.\n";
}


G4HadFinalState*
G4HESigmaZeroInelastic::ApplyYourself(const G4HadProjectile& aTrack,
                                      G4Nucleus& targetNucleus)
{
  G4HEVector* pv = new G4HEVector[MAXPART];
  const G4HadProjectile* aParticle = &aTrack;
  G4HEVector incidentParticle(aParticle);
     
  G4HELambdaInelastic theLambdaInelastic;
  theLambdaInelastic.SetMaxNumberOfSecondaries(MAXPART);
  theLambdaInelastic.SetVerboseLevel(verboseLevel);
    
  G4double incidentTotalMomentum = incidentParticle.getTotalMomentum();
  G4double pgam = G4UniformRand()*incidentTotalMomentum*0.75;
  G4HEVector incidentLambda; 
  incidentLambda.SmulAndUpdate(incidentParticle, 
                      (incidentTotalMomentum - pgam)/incidentTotalMomentum);                    
  G4DynamicParticle* aLambda = new G4DynamicParticle();
  aLambda->SetDefinition(G4Lambda::Lambda());
  aLambda->SetMomentum(incidentLambda.getMomentum());
  G4HadProjectile aLambdaTrack(*aLambda);
  G4HadFinalState* result =
          theLambdaInelastic.ApplyYourself(aLambdaTrack, targetNucleus);            
  vecLength = theLambdaInelastic.GetNumberOfSecondaries();
    
  pv[vecLength] = Gamma;
  pv[vecLength].setMomentum(incidentParticle.getMomentum());
  pv[vecLength].SmulAndUpdate( pv[vecLength],pgam/incidentTotalMomentum);
  G4DynamicParticle* aPhoton = new G4DynamicParticle();
  aPhoton->SetDefinition(G4Gamma::Gamma());
  aPhoton->SetMomentum(pv[vecLength].getMomentum());
  result->AddSecondary(aPhoton);
  delete [] pv;
  return result;
}