G4RPGInelastic.cc

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// $Id$
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#include "G4RPGInelastic.hh"
#include "Randomize.hh"
#include "G4PhysicalConstants.hh"
#include "G4SystemOfUnits.hh"
#include "G4HadReentrentException.hh"
#include "G4RPGStrangeProduction.hh"
#include "G4RPGTwoBody.hh"


G4RPGInelastic::G4RPGInelastic(const G4String& modelName)
  : G4HadronicInteraction(modelName)
{
  cache = 0.0;
  particleDef[0] = G4PionZero::PionZero();
  particleDef[1] = G4PionPlus::PionPlus();
  particleDef[2] = G4PionMinus::PionMinus();
  particleDef[3] = G4KaonPlus::KaonPlus();
  particleDef[4] = G4KaonMinus::KaonMinus();
  particleDef[5] = G4KaonZero::KaonZero();
  particleDef[6] = G4AntiKaonZero::AntiKaonZero();
  particleDef[7] = G4Proton::Proton();
  particleDef[8] = G4Neutron::Neutron();
  particleDef[9] = G4Lambda::Lambda();
  particleDef[10] = G4SigmaPlus::SigmaPlus();
  particleDef[11] = G4SigmaZero::SigmaZero();
  particleDef[12] = G4SigmaMinus::SigmaMinus();
  particleDef[13] = G4XiZero::XiZero();
  particleDef[14] = G4XiMinus::XiMinus();
  particleDef[15] = G4OmegaMinus::OmegaMinus();
  particleDef[16] = G4AntiProton::AntiProton();
  particleDef[17] = G4AntiNeutron::AntiNeutron();

  G4cout << " **************************************************** " << G4endl; 
  G4cout << " * The RPG model is currently under development and * " << G4endl; 
  G4cout << " * should not be used.                              * " << G4endl; 
  G4cout << " **************************************************** " << G4endl; 
}


G4double G4RPGInelastic::Pmltpc(G4int np, G4int nneg, G4int nz, 
                                G4int n, G4double b, G4double c)
{
  const G4double expxu =  82.;           // upper bound for arg. of exp
  const G4double expxl = -expxu;         // lower bound for arg. of exp
  G4double npf = 0.0;
  G4double nmf = 0.0;
  G4double nzf = 0.0;
  G4int i;
  for( i=2; i<=np; i++ )npf += std::log((double)i);
  for( i=2; i<=nneg; i++ )nmf += std::log((double)i);
  for( i=2; i<=nz; i++ )nzf += std::log((double)i);
  G4double r;
  r = std::min( expxu, std::max( expxl, -(np-nneg+nz+b)*(np-nneg+nz+b)/(2*c*c*n*n)-npf-nmf-nzf ) );
  return std::exp(r);
}


G4int G4RPGInelastic::Factorial( G4int n )
{
  G4int j = std::min(n,10);
  G4int result = 1;
  if (j <= 1) return result;
  for (G4int i = 2; i <= j; ++i) result *= i;
  return result;
}


G4bool G4RPGInelastic::MarkLeadingStrangeParticle(
     const G4ReactionProduct &currentParticle,
     const G4ReactionProduct &targetParticle,
     G4ReactionProduct &leadParticle )
{
  // The following was in GenerateXandPt and TwoCluster.
  // Add a parameter to the GenerateXandPt function telling it about the 
  // strange particle.
  //
  // Assumes that the original particle was a strange particle
  //
  G4bool lead = false;
  if( (currentParticle.GetMass() >= G4KaonPlus::KaonPlus()->GetPDGMass()) &&
      (currentParticle.GetDefinition() != G4Proton::Proton()) &&
      (currentParticle.GetDefinition() != G4Neutron::Neutron()) )
  {
    lead = true;
    leadParticle = currentParticle;              //  set lead to the incident particle
  }
  else if( (targetParticle.GetMass() >= G4KaonPlus::KaonPlus()->GetPDGMass()) &&
           (targetParticle.GetDefinition() != G4Proton::Proton()) &&
           (targetParticle.GetDefinition() != G4Neutron::Neutron()) )
  {
    lead = true;
    leadParticle = targetParticle;              //   set lead to the target particle
  }
  return lead;
}

 
 void G4RPGInelastic::SetUpPions(const G4int np, const G4int nneg, 
                                 const G4int nz,
                             G4FastVector<G4ReactionProduct,256> &vec,
                                 G4int &vecLen)
 {
   if( np+nneg+nz == 0 )return;
   G4int i;
   G4ReactionProduct *p;
   for( i=0; i<np; ++i )
   {
     p = new G4ReactionProduct;
     p->SetDefinition( G4PionPlus::PionPlus() );
     (G4UniformRand() < 0.5) ? p->SetSide( -1 ) : p->SetSide( 1 );
     vec.SetElement( vecLen++, p );
   }
   for( i=np; i<np+nneg; ++i )
   {
     p = new G4ReactionProduct;
     p->SetDefinition( G4PionMinus::PionMinus() );
     (G4UniformRand() < 0.5) ? p->SetSide( -1 ) : p->SetSide( 1 );
     vec.SetElement( vecLen++, p );
   }
   for( i=np+nneg; i<np+nneg+nz; ++i )
   {
     p = new G4ReactionProduct;
     p->SetDefinition( G4PionZero::PionZero() );
     (G4UniformRand() < 0.5) ? p->SetSide( -1 ) : p->SetSide( 1 );
     vec.SetElement( vecLen++, p );
   }
 }


 void G4RPGInelastic::GetNormalizationConstant(
   const G4double energy,  // MeV,  <0 means annihilation channels
   G4double &n,
   G4double &anpn )
  {
    const G4double expxu =  82.;          // upper bound for arg. of exp
    const G4double expxl = -expxu;        // lower bound for arg. of exp
    const G4int numSec = 60;
    //
    // the only difference between the calculation for annihilation channels
    // and normal is the starting value, iBegin, for the loop below
    //
    G4int iBegin = 1;
    G4double en = energy;
    if( energy < 0.0 )
    {
      iBegin = 2;
      en *= -1.0;
    }
    //
    // number of total particles vs. centre of mass Energy - 2*proton mass
    //
    G4double aleab = std::log(en/GeV);
    n = 3.62567 + aleab*(0.665843 + aleab*(0.336514 + aleab*(0.117712 + 0.0136912*aleab)));
    n -= 2.0;
    //
    // normalization constant for kno-distribution
    //
    anpn = 0.0;
    G4double test, temp;
    for( G4int i=iBegin; i<=numSec; ++i )
    {
      temp = pi*i/(2.0*n*n);
      test = std::exp( std::min( expxu, std::max( expxl, -(pi/4.0)*(i*i)/(n*n) ) ) );
      if( temp < 1.0 )
      {
        if( test >= 1.0e-10 )anpn += temp*test;
      }
      else
        anpn += temp*test;
    }
  }
 
void 
G4RPGInelastic::CalculateMomenta(G4FastVector<G4ReactionProduct,256>& vec,
                                 G4int& vecLen,
                                 const G4HadProjectile* originalIncident,
                                 const G4DynamicParticle* originalTarget,
                                 G4ReactionProduct& modifiedOriginal,
                                 G4Nucleus& targetNucleus,
                                 G4ReactionProduct& currentParticle,
                                 G4ReactionProduct& targetParticle,
                                 G4bool& incidentHasChanged,
                                 G4bool& targetHasChanged,
                                 G4bool quasiElastic)
{
  cache = 0;
  what = originalIncident->Get4Momentum().vect();

  G4ReactionProduct leadingStrangeParticle;

  //  strangeProduction.ReactionStage(originalIncident, modifiedOriginal,
  //                                  incidentHasChanged, originalTarget,
  //                                  targetParticle, targetHasChanged,
  //                                  targetNucleus, currentParticle,
  //                                  vec, vecLen,
  //                  false, leadingStrangeParticle);

  if( quasiElastic )
  {
    twoBody.ReactionStage(originalIncident, modifiedOriginal,
                          incidentHasChanged, originalTarget,
                          targetParticle, targetHasChanged,
                          targetNucleus, currentParticle,
                          vec, vecLen,
                          false, leadingStrangeParticle);
    return;
  }

  G4bool leadFlag = MarkLeadingStrangeParticle(currentParticle,
                                               targetParticle,
                                               leadingStrangeParticle );
  //
  // Note: the number of secondaries can be reduced in GenerateXandPt 
  // and TwoCluster
  //
  G4bool finishedGenXPt = false;
  G4bool annihilation = false;
  if( originalIncident->GetDefinition()->GetPDGEncoding() < 0 &&
      currentParticle.GetMass() == 0.0 && targetParticle.GetMass() == 0.0 )
  {
    // original was an anti-particle and annihilation has taken place
    annihilation = true;
    G4double ekcor = 1.0;
    G4double ek = originalIncident->GetKineticEnergy();
    G4double ekOrg = ek;
      
    const G4double tarmas = originalTarget->GetDefinition()->GetPDGMass();
    if( ek > 1.0*GeV )ekcor = 1./(ek/GeV);
    const G4double atomicWeight = targetNucleus.GetA_asInt();
    ek = 2*tarmas + ek*(1.+ekcor/atomicWeight);
    G4double tkin = targetNucleus.Cinema(ek);
    ek += tkin;
    ekOrg += tkin;
    //      modifiedOriginal.SetKineticEnergy( ekOrg );
    //
    // evaporation --  re-calculate black track energies
    //                 this was Done already just before the cascade
    //
    tkin = targetNucleus.AnnihilationEvaporationEffects(ek, ekOrg);
    ekOrg -= tkin;
    ekOrg = std::max( 0.0001*GeV, ekOrg );
    modifiedOriginal.SetKineticEnergy( ekOrg );
    G4double amas = originalIncident->GetDefinition()->GetPDGMass();
    G4double et = ekOrg + amas;
    G4double p = std::sqrt( std::abs(et*et-amas*amas) );
    G4double pp = modifiedOriginal.GetMomentum().mag();
    if( pp > 0.0 )
    {
      G4ThreeVector momentum = modifiedOriginal.GetMomentum();
      modifiedOriginal.SetMomentum( momentum * (p/pp) );
    }
    if( ekOrg <= 0.0001 )
    {
      modifiedOriginal.SetKineticEnergy( 0.0 );
      modifiedOriginal.SetMomentum( 0.0, 0.0, 0.0 );
    }
  }

  // twsup gives percentage of time two-cluster model is called

  const G4double twsup[] = { 1.0, 0.7, 0.5, 0.3, 0.2, 0.1 };
  G4double rand1 = G4UniformRand();
  G4double rand2 = G4UniformRand();

  // Cache current, target, and secondaries
  G4ReactionProduct saveCurrent = currentParticle;
  G4ReactionProduct saveTarget = targetParticle;
  std::vector<G4ReactionProduct> savevec;
  for (G4int i = 0; i < vecLen; i++) savevec.push_back(*vec[i]);

  // Call fragmentation code if
  //   1) there is annihilation, or
  //   2) there are more than 5 secondaries, or
  //   3) incident KE is > 1 GeV AND
  //        ( incident is a kaon AND rand < 0.5 OR twsup )
  //

  if( annihilation || vecLen > 5 ||
      ( modifiedOriginal.GetKineticEnergy()/GeV >= 1.0 &&

      (((originalIncident->GetDefinition() == G4KaonPlus::KaonPlus() ||
         originalIncident->GetDefinition() == G4KaonMinus::KaonMinus() ||
         originalIncident->GetDefinition() == G4KaonZeroLong::KaonZeroLong() ||
         originalIncident->GetDefinition() == G4KaonZeroShort::KaonZeroShort()) &&
      rand1 < 0.5) 
       || rand2 > twsup[vecLen]) ) )

    finishedGenXPt =
      fragmentation.ReactionStage(originalIncident, modifiedOriginal,
                                  incidentHasChanged, originalTarget,
                                  targetParticle, targetHasChanged,
                                  targetNucleus, currentParticle,
                                  vec, vecLen,
                                  leadFlag, leadingStrangeParticle);

  if (finishedGenXPt) return;

  G4bool finishedTwoClu = false;

  if (modifiedOriginal.GetTotalMomentum() < 1.0) {
    for (G4int i = 0; i < vecLen; i++) delete vec[i];
    vecLen = 0;

  } else {
    // Occaisionally, GenerateXandPt will fail in the annihilation channel.
    // Restore current, target and secondaries to pre-GenerateXandPt state
    // before trying annihilation in TwoCluster

    if (!finishedGenXPt && annihilation) {
      currentParticle = saveCurrent;
      targetParticle = saveTarget;
      for (G4int i = 0; i < vecLen; i++) delete vec[i];
      vecLen = 0;
      vec.Initialize( 0 );
      for (G4int i = 0; i < G4int(savevec.size()); i++) {
        G4ReactionProduct* p = new G4ReactionProduct;
        *p = savevec[i];
        vec.SetElement( vecLen++, p );
      }
    }

    // Big violations of energy conservation in this method - don't use
    // 
    //    pionSuppression.ReactionStage(originalIncident, modifiedOriginal,
    //                                  incidentHasChanged, originalTarget,
    //                                  targetParticle, targetHasChanged,
    //                                  targetNucleus, currentParticle,
    //                                  vec, vecLen,
    //                                  false, leadingStrangeParticle);

    try
    {
      finishedTwoClu = 
        twoCluster.ReactionStage(originalIncident, modifiedOriginal,
                                 incidentHasChanged, originalTarget,
                                 targetParticle, targetHasChanged,
                                 targetNucleus, currentParticle,
                                 vec, vecLen,
                                 leadFlag, leadingStrangeParticle);
    }
     catch(G4HadReentrentException aC)
    {
       aC.Report(G4cout);
       throw G4HadReentrentException(__FILE__, __LINE__, "Failing to calculate momenta");
    }
  }

  if (finishedTwoClu) return;

  twoBody.ReactionStage(originalIncident, modifiedOriginal,
                        incidentHasChanged, originalTarget,
                        targetParticle, targetHasChanged,
                        targetNucleus, currentParticle,
                        vec, vecLen,
                        false, leadingStrangeParticle);
}

/*
 void G4RPGInelastic::
 Rotate(G4FastVector<G4ReactionProduct,256> &vec, G4int &vecLen)
 {
   G4double rotation = 2.*pi*G4UniformRand();
   cache = rotation;
   G4int i;
   for( i=0; i<vecLen; ++i )
   {
     G4ThreeVector momentum = vec[i]->GetMomentum();
     momentum = momentum.rotate(rotation, what);
     vec[i]->SetMomentum(momentum);
   }
 }      
*/

void 
G4RPGInelastic::SetUpChange(G4FastVector<G4ReactionProduct,256>& vec,
                            G4int& vecLen,
                            G4ReactionProduct& currentParticle,
                            G4ReactionProduct& targetParticle,
                            G4bool& incidentHasChanged )
{
  theParticleChange.Clear();
  G4ParticleDefinition* aKaonZL = G4KaonZeroLong::KaonZeroLong();
  G4ParticleDefinition* aKaonZS = G4KaonZeroShort::KaonZeroShort();
  G4int i;

  if (currentParticle.GetDefinition() == particleDef[k0]) {
    if (G4UniformRand() < 0.5) {
      currentParticle.SetDefinitionAndUpdateE(aKaonZL);
      incidentHasChanged = true;
    } else {
      currentParticle.SetDefinitionAndUpdateE(aKaonZS);
    }
  } else if (currentParticle.GetDefinition() == particleDef[k0b]) {
    if (G4UniformRand() < 0.5) {
      currentParticle.SetDefinitionAndUpdateE(aKaonZL);
    } else {
      currentParticle.SetDefinitionAndUpdateE(aKaonZS);
      incidentHasChanged = true;
    }
  }

  if (targetParticle.GetDefinition() == particleDef[k0] || 
      targetParticle.GetDefinition() == particleDef[k0b] ) {
    if (G4UniformRand() < 0.5) {
      targetParticle.SetDefinitionAndUpdateE(aKaonZL);
    } else {
      targetParticle.SetDefinitionAndUpdateE(aKaonZS);
    }
  }

  for (i = 0; i < vecLen; ++i) {
    if (vec[i]->GetDefinition() == particleDef[k0] ||
        vec[i]->GetDefinition() == particleDef[k0b] ) {
      if (G4UniformRand() < 0.5) {
        vec[i]->SetDefinitionAndUpdateE(aKaonZL);
      } else {
        vec[i]->SetDefinitionAndUpdateE(aKaonZS);
      }
    }
  }

  if (incidentHasChanged) {
    G4DynamicParticle* p0 = new G4DynamicParticle;
    p0->SetDefinition(currentParticle.GetDefinition() );
    p0->SetMomentum(currentParticle.GetMomentum() );
    theParticleChange.AddSecondary( p0 );
    theParticleChange.SetStatusChange( stopAndKill );
    theParticleChange.SetEnergyChange( 0.0 );

  } else {
    G4double p = currentParticle.GetMomentum().mag()/MeV;
    G4ThreeVector mom = currentParticle.GetMomentum();
    if (p > DBL_MIN)
      theParticleChange.SetMomentumChange(mom.x()/p, mom.y()/p, mom.z()/p );
    else
      theParticleChange.SetMomentumChange(0.0, 0.0, 1.0);

    G4double aE = currentParticle.GetKineticEnergy();
    if (std::fabs(aE)<.1*eV) aE=.1*eV;
    theParticleChange.SetEnergyChange( aE );
  }

  if (targetParticle.GetMass() > 0.0)  // Tgt particle can be eliminated in TwoBody
  {
    G4ThreeVector momentum = targetParticle.GetMomentum();
    momentum = momentum.rotate(cache, what);
    G4double targKE = targetParticle.GetKineticEnergy();
    G4ThreeVector dir(0.0, 0.0, 1.0);
    if (targKE < DBL_MIN)
      targKE = DBL_MIN;
    else
      dir = momentum/momentum.mag();

    G4DynamicParticle* p1 = 
      new G4DynamicParticle(targetParticle.GetDefinition(), dir, targKE);

    theParticleChange.AddSecondary( p1 );
  }

  G4DynamicParticle* p;
  for (i = 0; i < vecLen; ++i) {
    G4double secKE = vec[i]->GetKineticEnergy();
    G4ThreeVector momentum = vec[i]->GetMomentum();
    G4ThreeVector dir(0.0, 0.0, 1.0);
    if (secKE < DBL_MIN)
      secKE = DBL_MIN;
    else
      dir = momentum/momentum.mag();

    p = new G4DynamicParticle(vec[i]->GetDefinition(), dir, secKE);
    theParticleChange.AddSecondary( p );
    delete vec[i];
  }
}


std::pair<G4int, G4double>
G4RPGInelastic::interpolateEnergy(G4double e) const
{
  G4int index = 29;
  G4double fraction = 0.0;

  for (G4int i = 1; i < 30; i++) {
    if (e < energyScale[i]) {
      index = i-1;
      fraction = (e - energyScale[index]) / (energyScale[i] - energyScale[index]);
      break;
    }
  }
  return std::pair<G4int, G4double>(index, fraction);
}


G4int
G4RPGInelastic::sampleFlat(std::vector<G4double> sigma) const
{
  G4int i;
  G4double sum(0.);
  for (i = 0; i < G4int(sigma.size()); i++) sum += sigma[i];

  G4double fsum = sum*G4UniformRand();
  G4double partialSum = 0.0;
  G4int channel = 0;

  for (i = 0; i < G4int(sigma.size()); i++) {
    partialSum += sigma[i];
    if (fsum < partialSum) {
      channel = i;
      break;
    }
  }

  return channel;
}


void G4RPGInelastic::CheckQnums(G4FastVector<G4ReactionProduct,256> &vec,
                                G4int &vecLen,
                                G4ReactionProduct &currentParticle,
                                G4ReactionProduct &targetParticle,
                                G4double Q, G4double B, G4double S)
{
  G4ParticleDefinition* projDef = currentParticle.GetDefinition();
  G4ParticleDefinition* targDef = targetParticle.GetDefinition();
  G4double chargeSum = projDef->GetPDGCharge() + targDef->GetPDGCharge();
  G4double baryonSum = projDef->GetBaryonNumber() + targDef->GetBaryonNumber();
  G4double strangenessSum = projDef->GetQuarkContent(3) - 
                            projDef->GetAntiQuarkContent(3) + 
                            targDef->GetQuarkContent(3) -
                            targDef->GetAntiQuarkContent(3);

  G4ParticleDefinition* secDef = 0;
  for (G4int i = 0; i < vecLen; i++) {
    secDef = vec[i]->GetDefinition();
    chargeSum += secDef->GetPDGCharge();
    baryonSum += secDef->GetBaryonNumber();
    strangenessSum += secDef->GetQuarkContent(3) 
                    - secDef->GetAntiQuarkContent(3);
  }

  G4bool OK = true;
  if (chargeSum != Q) {
    G4cout << " Charge not conserved " << G4endl;
    OK = false;
  }
  if (baryonSum != B) {
    G4cout << " Baryon number not conserved " << G4endl;
    OK = false;
  }
  if (strangenessSum != S) {
    G4cout << " Strangeness not conserved " << G4endl;
    OK = false;
  } 

  if (!OK) {
    G4cout << " projectile: " << projDef->GetParticleName() 
           << "  target: " << targDef->GetParticleName() << G4endl;
    for (G4int i = 0; i < vecLen; i++) {
      secDef = vec[i]->GetDefinition();
      G4cout << secDef->GetParticleName() << " " ;
    }
    G4cout << G4endl;
  }

}


const G4double G4RPGInelastic::energyScale[30] = {
  0.0,  0.01, 0.013, 0.018, 0.024, 0.032, 0.042, 0.056, 0.075, 0.1,
  0.13, 0.18, 0.24,  0.32,  0.42,  0.56,  0.75,  1.0,   1.3,   1.8,
  2.4,  3.2,  4.2,   5.6,   7.5,   10.0,  13.0,  18.0,  24.0, 32.0 };


/* end of file */