G4LEAntiKaonZeroInelastic.cc

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// $Id$
//
// Hadronic Process: Low Energy KaonZeroLong Inelastic Process
// J.L. Chuma, TRIUMF, 11-Feb-1997
// Modified by J.L.Chuma 30-Apr-97: added originalTarget for CalculateMomenta
 
#include "G4LEAntiKaonZeroInelastic.hh"
#include "G4PhysicalConstants.hh"
#include "G4SystemOfUnits.hh"
#include "Randomize.hh"
#include "G4HadReentrentException.hh"
 
 
void G4LEAntiKaonZeroInelastic::ModelDescription(std::ostream& outFile) const
{
  outFile << "G4LEAntiKaonZeroInelastic is one of the Low Energy\n"
          << "Parameterized (LEP) models used to implement anti-K0 scattering\n"
          << "from nuclei.  It is a re-engineered version of the GHEISHA code\n"
          << "of H. Fesefeldt.  It divides the initial collision products\n"
          << "into backward- and forward-going clusters which are then\n"
          << "decayed into final state hadrons.  The model does not conserve\n"
          << "energy on an event-by-event basis.  It may be applied to\n"
          << "anti-K0s with initial energies between 0 and 25 GeV.\n";
}
 
 
G4HadFinalState*
G4LEAntiKaonZeroInelastic::ApplyYourself(const G4HadProjectile& aTrack,
                                         G4Nucleus& targetNucleus)
{    
  const G4HadProjectile* originalIncident = &aTrack;
 
  // create the target particle
  G4DynamicParticle *originalTarget = targetNucleus.ReturnTargetParticle();
    
  if (verboseLevel > 1) {
    const G4Material *targetMaterial = aTrack.GetMaterial();
    G4cout << "G4LEAntiKaonZeroInelastic::ApplyYourself called" << G4endl;    
    G4cout << "kinetic energy = " << originalIncident->GetKineticEnergy()/MeV << "MeV, ";
    G4cout << "target material = " << targetMaterial->GetName() << ", ";
    G4cout << "target particle = " << originalTarget->GetDefinition()->GetParticleName()
           << G4endl;
  }
 
  // Fermi motion and evaporation
  // As of Geant3, the Fermi energy calculation had not been Done
  G4double ek = originalIncident->GetKineticEnergy()/MeV;
  G4double amas = originalIncident->GetDefinition()->GetPDGMass()/MeV;
  G4ReactionProduct modifiedOriginal;
  modifiedOriginal = *originalIncident;
    
  G4double tkin = targetNucleus.Cinema( ek );
  ek += tkin;
  modifiedOriginal.SetKineticEnergy( ek*MeV );
  G4double et = ek + amas;
  G4double p = std::sqrt( std::abs((et-amas)*(et+amas)) );
  G4double pp = modifiedOriginal.GetMomentum().mag()/MeV;
  if (pp > 0.0) {
    G4ThreeVector momentum = modifiedOriginal.GetMomentum();
    modifiedOriginal.SetMomentum( momentum * (p/pp) );
  }
 
  // calculate black track energies
  tkin = targetNucleus.EvaporationEffects( ek );
  ek -= tkin;
  modifiedOriginal.SetKineticEnergy( ek*MeV );
  et = ek + amas;
  p = std::sqrt( std::abs((et-amas)*(et+amas)) );
  pp = modifiedOriginal.GetMomentum().mag()/MeV;
  if (pp > 0.0) {
    G4ThreeVector momentum = modifiedOriginal.GetMomentum();
    modifiedOriginal.SetMomentum( momentum * (p/pp) );
  }
 
  G4ReactionProduct currentParticle = modifiedOriginal;
  G4ReactionProduct targetParticle;
  targetParticle = *originalTarget;
  currentParticle.SetSide( 1 ); // incident always goes in forward hemisphere
  targetParticle.SetSide( -1 );  // target always goes in backward hemisphere
  G4bool incidentHasChanged = false;
  G4bool targetHasChanged = false;
  G4bool quasiElastic = false;
  G4FastVector<G4ReactionProduct,GHADLISTSIZE> vec;  // vec will contain the secondary particles
  G4int vecLen = 0;
  vec.Initialize( 0 );
    
  const G4double cutOff = 0.1;
  if (currentParticle.GetKineticEnergy()/MeV > cutOff)
    Cascade(vec, vecLen,
            originalIncident, currentParticle, targetParticle,
            incidentHasChanged, targetHasChanged, quasiElastic);
    
  try {
    CalculateMomenta(vec, vecLen, originalIncident, originalTarget,
                     modifiedOriginal, targetNucleus, currentParticle,
                     targetParticle, incidentHasChanged, targetHasChanged,
                     quasiElastic);
  }
  catch(G4HadReentrentException aR)
  {
    aR.Report(G4cout);
    throw G4HadReentrentException(__FILE__, __LINE__, "Bailing out");
  }
  SetUpChange(vec, vecLen, currentParticle, targetParticle, incidentHasChanged);
 
  if (isotopeProduction) DoIsotopeCounting(originalIncident, targetNucleus);    
  delete originalTarget;
  return &theParticleChange;
}
 
 
void G4LEAntiKaonZeroInelastic::Cascade(
   G4FastVector<G4ReactionProduct,GHADLISTSIZE> &vec,
   G4int& vecLen,
   const G4HadProjectile *originalIncident,
   G4ReactionProduct &currentParticle,
   G4ReactionProduct &targetParticle,
   G4bool &incidentHasChanged,
   G4bool &targetHasChanged,
   G4bool &quasiElastic)
{
  // derived from original FORTRAN code CASK0B by H. Fesefeldt (13-Sep-1987)
  //
  // K0Long undergoes interaction with nucleon within a nucleus.  Check if it is
  // energetically possible to produce pions/kaons.  In not, assume nuclear excitation
  // occurs and input particle is degraded in energy. No other particles are produced.
  // If reaction is possible, find the correct number of pions/protons/neutrons
  // produced using an interpolation to multiplicity data.  Replace some pions or
  // protons/neutrons by kaons or strange baryons according to the average
  // multiplicity per Inelastic reaction.
 
  const G4double mOriginal = originalIncident->GetDefinition()->GetPDGMass()/MeV;
  const G4double etOriginal = originalIncident->Get4Momentum().e()/MeV;
  const G4double pOriginal = originalIncident->Get4Momentum().vect().mag()/MeV;
  const G4double targetMass = targetParticle.GetMass()/MeV;
  G4double centerofmassEnergy = std::sqrt(mOriginal*mOriginal +
                                          targetMass*targetMass +
                                          2.0*targetMass*etOriginal );
  G4double availableEnergy = centerofmassEnergy - (targetMass+mOriginal);
 
  static G4bool first = true;
  const G4int numMul = 1200;
  const G4int numSec = 60;
  static G4double protmul[numMul], protnorm[numSec]; // proton constants
  static G4double neutmul[numMul], neutnorm[numSec]; // neutron constants
 
  // npos = number of pi+, nneg = number of pi-, nzero = number of pi0
  G4int counter;
  G4int nt = 0;
  G4int npos = 0, nneg = 0, nzero = 0;
  const G4double c = 1.25;    
  const G4double b[] = { 0.7, 0.7 };
  if (first) {  // Computation of normalization constants will only be done once
    first = false;
    G4int i;
    for (i = 0; i < numMul; ++i) protmul[i] = 0.0;
    for (i = 0; i < numSec; ++i) protnorm[i] = 0.0;
    counter = -1;
    for (npos = 0; npos < numSec/3; ++npos) { 
      for (nneg = std::max(0,npos - 2); nneg <= npos; ++nneg) {
        for (nzero = 0; nzero < numSec/3; ++nzero) {
          if (++counter < numMul) {
            nt = npos + nneg + nzero;
            if (nt > 0 && nt <= numSec) {
              protmul[counter] = Pmltpc(npos, nneg, nzero, nt, b[0], c);
              protnorm[nt-1] += protmul[counter];
            }
          }
        }
      }
    }
 
    for (i = 0; i < numMul; ++i) neutmul[i] = 0.0;
    for (i = 0; i < numSec; ++i) neutnorm[i] = 0.0;
    counter = -1;
    for (npos = 0; npos < (numSec/3); ++npos) {
      for (nneg = std::max(0,npos-1); nneg <= (npos+1); ++nneg) {
        for (nzero = 0; nzero < numSec/3; ++nzero) {
          if (++counter < numMul) {
            nt = npos + nneg + nzero;
            if (nt > 0 && nt <= numSec) {
              neutmul[counter] = Pmltpc(npos, nneg, nzero, nt, b[1], c);
              neutnorm[nt-1] += neutmul[counter];
            }
          }
        }
      }
    }
 
    for (i = 0; i < numSec; ++i) {
      if( protnorm[i] > 0.0 )protnorm[i] = 1.0/protnorm[i];
      if( neutnorm[i] > 0.0 )neutnorm[i] = 1.0/neutnorm[i];
    }
  }   // end of initialization
    
  const G4double expxu = 82.;           // upper bound for arg. of exp
  const G4double expxl = -expxu;        // lower bound for arg. of exp
  G4ParticleDefinition* aKaonMinus = G4KaonMinus::KaonMinus();
  G4ParticleDefinition* aKaonZS = G4KaonZeroShort::KaonZeroShort();
  G4ParticleDefinition* aKaonZL = G4KaonZeroLong::KaonZeroLong();
  G4ParticleDefinition *aNeutron = G4Neutron::Neutron();
  G4ParticleDefinition *aProton = G4Proton::Proton();
  G4ParticleDefinition *aPiPlus = G4PionPlus::PionPlus();
  G4ParticleDefinition *aPiMinus = G4PionMinus::PionMinus();
  G4ParticleDefinition *aPiZero = G4PionZero::PionZero();
  G4ParticleDefinition *aLambda = G4Lambda::Lambda();
  G4ParticleDefinition *aSigmaPlus = G4SigmaPlus::SigmaPlus();
  G4ParticleDefinition *aSigmaMinus = G4SigmaMinus::SigmaMinus();
  G4ParticleDefinition *aSigmaZero = G4SigmaZero::SigmaZero();
  const G4double cech[] = {1.,1.,1.,0.70,0.60,0.55,0.35,0.25,0.18,0.15};
  G4int iplab = G4int(std::min( 9.0, 5.0*pOriginal*MeV/GeV ));
  if ((pOriginal*MeV/GeV <= 2.0) && (G4UniformRand() < cech[iplab]) ) {
    npos = nneg = nzero = nt = 0;
    iplab = G4int(std::min( 19.0, pOriginal*MeV/GeV*10.0 ));
    const G4double cnk0[] = {0.17,0.18,0.17,0.24,0.26,0.20,0.22,0.21,0.34,0.45,
                             0.58,0.55,0.36,0.29,0.29,0.32,0.32,0.33,0.33,0.33};
    if (G4UniformRand() > cnk0[iplab]) {
      G4double ran = G4UniformRand();
      if (ran < 0.25) {
        // k0Long n --> pi- s+
        if (targetParticle.GetDefinition() == aNeutron) {
          currentParticle.SetDefinitionAndUpdateE(aPiMinus);
          targetParticle.SetDefinitionAndUpdateE(aSigmaPlus);
          incidentHasChanged = true;
          targetHasChanged = true;
        }
      } else if( ran < 0.50 ) {
        // k0Long p --> pi+ s0  or  k0Long n --> pi0 s0
          if( targetParticle.GetDefinition() == aNeutron )
            currentParticle.SetDefinitionAndUpdateE( aPiZero );
          else
            currentParticle.SetDefinitionAndUpdateE( aPiPlus );
          targetParticle.SetDefinitionAndUpdateE( aSigmaZero );
          incidentHasChanged = true;
          targetHasChanged = true;
      } else if (ran < 0.75) {
        // k0Long n --> pi+ s-
          if( targetParticle.GetDefinition() == aNeutron )
          {
            currentParticle.SetDefinitionAndUpdateE( aPiPlus );
            targetParticle.SetDefinitionAndUpdateE( aSigmaMinus );
            incidentHasChanged = true;
            targetHasChanged = true;
          }
      } else {
        // k0Long p --> pi+ L  or  k0Long n --> pi0 L
          if( targetParticle.GetDefinition() == aNeutron )
            currentParticle.SetDefinitionAndUpdateE( aPiZero );
          else
            currentParticle.SetDefinitionAndUpdateE( aPiPlus );
          targetParticle.SetDefinitionAndUpdateE( aLambda );
          incidentHasChanged = true;
          targetHasChanged = true;
      }
    } else {
      // ran <= cnk0
      quasiElastic = true;
      if (targetParticle.GetDefinition() == aNeutron) {
          currentParticle.SetDefinitionAndUpdateE( aKaonMinus );
          targetParticle.SetDefinitionAndUpdateE( aProton );
          incidentHasChanged = true;
          targetHasChanged = true;
      }
    }
  } else {
    // (pOriginal > 2.0*GeV) || (random number >= cech[iplab])
    if (availableEnergy < aPiPlus->GetPDGMass()/MeV) {
      quasiElastic = true;
      return;
    }
    G4double n, anpn;
    GetNormalizationConstant( availableEnergy, n, anpn );
    G4double ran = G4UniformRand();
    G4double dum, test, excs = 0.0;
    if (targetParticle.GetDefinition() == aProton) {
      counter = -1;
      for (npos = 0; (npos < numSec/3) && (ran >= excs); ++npos) {
        for (nneg = std::max(0,npos-2); nneg <= npos && ran >= excs; ++nneg) {
          for (nzero = 0; nzero < numSec/3 && ran >= excs; ++nzero) {
            if (++counter < numMul) {
              nt = npos + nneg +nzero;
              if (nt > 0 && nt <= numSec) {
                test = std::exp(std::min(expxu,
                                std::max(expxl, -(pi/4.0)*(nt*nt)/(n*n) ) ) );
                dum = (pi/anpn)*nt*protmul[counter]*protnorm[nt-1]/(2.0*n*n);
                if (std::fabs(dum) < 1.0) {
                  if( test >= 1.0e-10 )excs += dum*test;
                } else {
                  excs += dum*test;
                }
              }
            }
          }
        }
      }
      if (ran >= excs) {
        // 3 previous loops continued to the end
        quasiElastic = true;
        return;
      }
      npos--; nneg--; nzero--;
      switch (npos - nneg)
      {
        case 1:
          if (G4UniformRand() < 0.5) {
            currentParticle.SetDefinitionAndUpdateE(aKaonMinus);
            incidentHasChanged = true;
          } else {
            targetParticle.SetDefinitionAndUpdateE(aNeutron);
            targetHasChanged = true;
          }
        case 0:
          break;
        default:
          currentParticle.SetDefinitionAndUpdateE(aKaonMinus);
          targetParticle.SetDefinitionAndUpdateE(aNeutron);
          incidentHasChanged = true;
          targetHasChanged = true;
          break;
      }
    } else {
      // target must be a neutron
      counter = -1;
      for (npos = 0; npos < numSec/3 && ran >= excs; ++npos) {
        for (nneg = std::max(0,npos-1); nneg <= (npos+1) && ran >= excs; ++nneg) {
          for (nzero = 0; nzero < numSec/3 && ran >= excs; ++nzero) {
            if (++counter < numMul) {
              nt = npos + nneg + nzero;
              if (nt > 0 && nt <= numSec) {
                test = std::exp(std::min(expxu,
                                std::max(expxl, -(pi/4.0)*(nt*nt)/(n*n) ) ) );
                dum = (pi/anpn)*nt*neutmul[counter]*neutnorm[nt-1]/(2.0*n*n);
                if (std::fabs(dum) < 1.0) {
                  if (test >= 1.0e-10) excs += dum*test;
                } else {
                  excs += dum*test;
                }
              }
            }
          }
        }
      }
      if (ran >= excs) {
        // 3 previous loops continued to the end
        quasiElastic = true;
        return;
      }
      npos--; nneg--; nzero--;
      switch (npos - nneg)
      {
        case 0:
          currentParticle.SetDefinitionAndUpdateE(aKaonMinus);
          targetParticle.SetDefinitionAndUpdateE(aProton);
          incidentHasChanged = true;
          targetHasChanged = true;
          break;
        case 1:
          currentParticle.SetDefinitionAndUpdateE(aKaonMinus);
          incidentHasChanged = true;
          break;
        default:
          targetParticle.SetDefinitionAndUpdateE(aProton);
          targetHasChanged = true;
          break;
      }
    }
 
    if (G4UniformRand() >= 0.5) {
      if (currentParticle.GetDefinition() == aKaonMinus &&
          targetParticle.GetDefinition() == aNeutron) {
        ran = G4UniformRand();
        if (ran < 0.68) {
          currentParticle.SetDefinitionAndUpdateE(aPiMinus);
          targetParticle.SetDefinitionAndUpdateE(aLambda);
        } else if (ran < 0.84) {
          currentParticle.SetDefinitionAndUpdateE(aPiMinus);
          targetParticle.SetDefinitionAndUpdateE(aSigmaZero);
        } else {
          currentParticle.SetDefinitionAndUpdateE(aPiZero);
          targetParticle.SetDefinitionAndUpdateE(aSigmaMinus);
        }
      } else if ((currentParticle.GetDefinition() == aKaonZS ||
                  currentParticle.GetDefinition() == aKaonZL) &&
                  targetParticle.GetDefinition() == aProton) {
        ran = G4UniformRand();
        if (ran < 0.68) {
          currentParticle.SetDefinitionAndUpdateE(aPiPlus);
          targetParticle.SetDefinitionAndUpdateE(aLambda);
        } else if (ran < 0.84) {
          currentParticle.SetDefinitionAndUpdateE(aPiZero);
          targetParticle.SetDefinitionAndUpdateE(aSigmaPlus);
        } else {
          currentParticle.SetDefinitionAndUpdateE(aPiPlus);
          targetParticle.SetDefinitionAndUpdateE(aSigmaZero);
        }
      } else {
        ran = G4UniformRand();
        if (ran < 0.67) {
          currentParticle.SetDefinitionAndUpdateE(aPiZero);
          targetParticle.SetDefinitionAndUpdateE(aLambda);
        } else if (ran < 0.78) {
          currentParticle.SetDefinitionAndUpdateE(aPiMinus);
          targetParticle.SetDefinitionAndUpdateE(aSigmaPlus);
        } else if (ran < 0.89) {
          currentParticle.SetDefinitionAndUpdateE(aPiZero);
          targetParticle.SetDefinitionAndUpdateE(aSigmaZero);
        } else {
          currentParticle.SetDefinitionAndUpdateE(aPiPlus);
          targetParticle.SetDefinitionAndUpdateE(aSigmaMinus);
        }
      }
      incidentHasChanged = true;
      targetHasChanged = true;
    }
  }
 
  if (currentParticle.GetDefinition() == aKaonZL) {
    if (G4UniformRand() >= 0.5) {
      currentParticle.SetDefinitionAndUpdateE(aKaonZS);
      incidentHasChanged = true;
    }
  }
  if (targetParticle.GetDefinition() == aKaonZL) {
    if (G4UniformRand() >= 0.5) {
      targetParticle.SetDefinitionAndUpdateE(aKaonZS);
      targetHasChanged = true;
    }
  }
  SetUpPions(npos, nneg, nzero, vec, vecLen);
  return;
}
 
 /* end of file */