G4XAqmTotal.cc

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//
// -------------------------------------------------------------------
//      GEANT4 Class file
//
//      For information related to this code contact:
//
//      File name:     G4XAqmTotal
//
//      Author:        
// 
//      Creation date: 15 April 1999
//
//      Modifications: 
//      
// Additive Quark Model total cross section 
// (H.J. Lipkin and F. Scheck, Phys.Rev. 16 (1966) 71
//
// -------------------------------------------------------------------

#include "globals.hh"
#include "G4ios.hh"
#include "G4SystemOfUnits.hh"
#include "G4XAqmTotal.hh"
#include "G4KineticTrack.hh"
#include "G4ParticleDefinition.hh"


// Validity range of this cross-section
const G4double G4XAqmTotal::_lowLimit = 0.;
const G4double G4XAqmTotal::_highLimit = DBL_MAX;

G4XAqmTotal::G4XAqmTotal()
{ 
  // As a first approximation the model is assumed to be valid over 
  // the entire energy range
}


G4XAqmTotal::~G4XAqmTotal()
{ }


G4bool G4XAqmTotal::operator==(const G4XAqmTotal &right) const
{
  return (this == (G4XAqmTotal *) &right);
}


G4bool G4XAqmTotal::operator!=(const G4XAqmTotal &right) const
{
  return (this != (G4XAqmTotal *) &right);
}


G4double G4XAqmTotal::CrossSection(const G4KineticTrack& trk1, const G4KineticTrack& trk2) const
{
  G4double sigma = 0.;

  // Get strangeness content
  const G4ParticleDefinition* def1 = trk1.GetDefinition();
  G4int sTrk1 = def1->GetQuarkContent(3) + def1->GetAntiQuarkContent(3);
  const G4ParticleDefinition* def2 = trk2.GetDefinition();
  G4int sTrk2 = def2->GetQuarkContent(3) + def2->GetAntiQuarkContent(3);
  
  // Get non-strange quark content
  G4int qTrk1 = def1->GetQuarkContent(1) + def1->GetAntiQuarkContent(1) +
                def1->GetQuarkContent(2) + def1->GetAntiQuarkContent(2) +
                def1->GetQuarkContent(4) + def1->GetAntiQuarkContent(4) +
                def1->GetQuarkContent(5) + def1->GetAntiQuarkContent(5) +
                def1->GetQuarkContent(6) + def1->GetAntiQuarkContent(6);

  G4int qTrk2 = def2->GetQuarkContent(1) + def2->GetAntiQuarkContent(1) +
                def2->GetQuarkContent(2) + def2->GetAntiQuarkContent(2) +
                def2->GetQuarkContent(4) + def2->GetAntiQuarkContent(4) +
                def2->GetQuarkContent(5) + def2->GetAntiQuarkContent(5) +
                def2->GetQuarkContent(6) + def2->GetAntiQuarkContent(6);

  G4double sRatio1 = 0.;
  if (qTrk1 != 0) sRatio1 = sTrk1 / qTrk1;
  
  G4double sRatio2 = 0.;
  if (qTrk2 != 0) sRatio2 = sTrk2 / qTrk2;
  
  // Calculate the number of colliding mesons
  G4int nMesons = 0;
  G4int nQ1 = sTrk1 + qTrk1;

  if (nQ1 == 2) nMesons++;
  G4int nQ2 = sTrk2 + qTrk2;
  if (nQ2 == 2) nMesons++;

  // Cross-section (units to be checked!)
  sigma = 40. * std::pow((2.0/3.0),nMesons) * (1. - 0.4 * sRatio1) * (1. - 0.4 * sRatio2) * millibarn;

  return sigma;
}


G4String G4XAqmTotal::Name() const
{
  G4String name("AqmTotalCrossSection");
  return name;
}



G4bool G4XAqmTotal::IsValid(G4double e) const
{
  G4bool answer = InLimits(e,_lowLimit,_highLimit);

  return answer;
}