G4RPGAntiKZeroInelastic.cc

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// $Id$
//
 
#include "G4RPGAntiKZeroInelastic.hh"
#include "Randomize.hh"
#include "G4PhysicalConstants.hh"
#include "G4SystemOfUnits.hh"
#include "G4HadReentrentException.hh"

 G4HadFinalState *
  G4RPGAntiKZeroInelastic::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 << "G4RPGAntiKZeroInelastic::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 );
    
    delete originalTarget;
    return &theParticleChange;
  }
 
void G4RPGAntiKZeroInelastic::Cascade(
   G4FastVector<G4ReactionProduct,GHADLISTSIZE> &vec,
   G4int& vecLen,
   const G4HadProjectile *originalIncident,
   G4ReactionProduct &currentParticle,
   G4ReactionProduct &targetParticle,
   G4bool &incidentHasChanged,
   G4bool &targetHasChanged,
   G4bool &quasiElastic )
{
  // Derived from H. Fesefeldt's original FORTRAN code CASK0B
  //
  // 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

  // np = number of pi+, nneg = number of pi-, nz = number of pi0

  G4int counter, nt=0, np=0, nneg=0, nz=0;
  const G4double c = 1.25;    
  const G4double b[] = { 0.7, 0.7 };
  if( first )       // compute normalization constants, this 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( np=0; np<numSec/3; ++np )
      {
        for( nneg=std::max(0,np-2); nneg<=np; ++nneg )
        {
          for( nz=0; nz<numSec/3; ++nz )
          {
            if( ++counter < numMul )
            {
              nt = np+nneg+nz;
              if( nt>0 && nt<=numSec )
              {
                protmul[counter] = Pmltpc(np,nneg,nz,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( np=0; np<(numSec/3); ++np )
      {
        for( nneg=std::max(0,np-1); nneg<=(np+1); ++nneg )
        {
          for( nz=0; nz<numSec/3; ++nz )
          {
            if( ++counter < numMul )
            {
              nt = np+nneg+nz;
              if( nt>0 && nt<=numSec )
              {
                neutmul[counter] = Pmltpc(np,nneg,nz,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]) ) {
    np = nneg = nz = 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( np=0; (np<numSec/3) && (ran>=excs); ++np )
        {
          for( nneg=std::max(0,np-2); nneg<=np && ran>=excs; ++nneg )
          {
            for( nz=0; nz<numSec/3 && ran>=excs; ++nz )
            {
              if( ++counter < numMul )
              {
                nt = np+nneg+nz;
                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;
        }
        np--; nneg--; nz--;
        switch( np-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( np=0; np<numSec/3 && ran>=excs; ++np )
        {
          for( nneg=std::max(0,np-1); nneg<=(np+1) && ran>=excs; ++nneg )
          {
            for( nz=0; nz<numSec/3 && ran>=excs; ++nz )
            {
              if( ++counter < numMul )
              {
                nt = np+nneg+nz;
                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;
        }
        np--; nneg--; nz--;
        switch( np-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( np, nneg, nz, vec, vecLen );
    return;
}

 /* end of file */
 

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