G4HEAntiKaonZeroInelastic.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 is 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 "G4HEAntiKaonZeroInelastic.hh"
#include "globals.hh"
#include "G4ios.hh"
#include "G4PhysicalConstants.hh"
#include "G4SystemOfUnits.hh"

G4HEAntiKaonZeroInelastic::G4HEAntiKaonZeroInelastic(const G4String& name)
 : G4HEInelastic(name)
{
  vecLength = 0;
  theMinEnergy = 20*GeV;
  theMaxEnergy = 10*TeV;
  MAXPART      = 2048;
  verboseLevel = 0;
  G4cout << "WARNING: model G4HEAntiKaonZeroInelastic is being deprecated and will\n"
         << "disappear in Geant4 version 10.0"  << G4endl;  
}


void G4HEAntiKaonZeroInelastic::ModelDescription(std::ostream& outFile) const
{
  outFile << "G4HEAntiKaonZeroInelastic is one of the High Energy\n"
          << "Parameterized (HEP) models used to implement inelastic\n"
          << "anti-K0 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 anti-K0 with initial energies\n"
          << "above 20 GeV.\n";
}


G4HadFinalState*
G4HEAntiKaonZeroInelastic::ApplyYourself(const G4HadProjectile& aTrack,
                                         G4Nucleus& targetNucleus)
{
  G4HEVector* pv = new G4HEVector[MAXPART];
  const G4HadProjectile* aParticle = &aTrack;
  const G4double atomicWeight = targetNucleus.GetA_asInt();
  const G4double atomicNumber = targetNucleus.GetZ_asInt();
  G4HEVector incidentParticle(aParticle);

  G4int incidentCode = incidentParticle.getCode();
  G4double incidentMass = incidentParticle.getMass();
  G4double incidentTotalEnergy = incidentParticle.getEnergy();

  // G4double incidentTotalMomentum = incidentParticle.getTotalMomentum();
  //  DHW 19 May 2011: variable set but not used
 
  G4double incidentKineticEnergy = incidentTotalEnergy - incidentMass;

  if (incidentKineticEnergy < 1.)
    G4cout << "GHEAntiKaonZeroInelastic: incident energy < 1 GeV" << G4endl;

  if (verboseLevel > 1) {
    G4cout << "G4HEAntiKaonZeroInelastic::ApplyYourself" << G4endl;
    G4cout << "incident particle " << incidentParticle.getName()
           << "mass "              << incidentMass
           << "kinetic energy "    << incidentKineticEnergy
           << G4endl;
    G4cout << "target material with (A,Z) = (" 
           << atomicWeight << "," << atomicNumber << ")" << G4endl;
  }
    
  G4double inelasticity = NuclearInelasticity(incidentKineticEnergy, 
                                              atomicWeight, atomicNumber);
  if (verboseLevel > 1)
    G4cout << "nuclear inelasticity = " << inelasticity << G4endl;
    
  incidentKineticEnergy -= inelasticity;
    
  G4double excitationEnergyGNP = 0.;
  G4double excitationEnergyDTA = 0.; 

  G4double excitation = NuclearExcitation(incidentKineticEnergy,
                                          atomicWeight, atomicNumber,
                                          excitationEnergyGNP,
                                          excitationEnergyDTA);
  if (verboseLevel > 1)
    G4cout << "nuclear excitation = " << excitation << excitationEnergyGNP 
           << excitationEnergyDTA << G4endl;             


  incidentKineticEnergy -= excitation;
  incidentTotalEnergy = incidentKineticEnergy + incidentMass;
  // incidentTotalMomentum = std::sqrt( (incidentTotalEnergy-incidentMass)
  //                                  *(incidentTotalEnergy+incidentMass));
  // DHW 19 May 2011: variable set but not used

  G4HEVector targetParticle;
  if (G4UniformRand() < atomicNumber/atomicWeight) { 
    targetParticle.setDefinition("Proton");
  } else { 
    targetParticle.setDefinition("Neutron");
  }

  G4double targetMass = targetParticle.getMass();
  G4double centerOfMassEnergy = std::sqrt(incidentMass*incidentMass
                                         + targetMass*targetMass
                                         + 2.0*targetMass*incidentTotalEnergy);
  G4double availableEnergy = centerOfMassEnergy - targetMass - incidentMass;

  vecLength = 0;           
        
  if (verboseLevel > 1)
    G4cout << "ApplyYourself: CallFirstIntInCascade for particle "
           << incidentCode << G4endl;

  G4bool successful = false; 

  G4bool inElastic = true; 
  FirstIntInCasAntiKaonZero(inElastic, availableEnergy, pv, vecLength,
                            incidentParticle, targetParticle );

  if (verboseLevel > 1)
    G4cout << "ApplyYourself::StrangeParticlePairProduction" << G4endl;

  if ((vecLength > 0) && (availableEnergy > 1.)) 
    StrangeParticlePairProduction(availableEnergy, centerOfMassEnergy,
                                  pv, vecLength,
                                  incidentParticle, targetParticle);
  HighEnergyCascading(successful, pv, vecLength,
                      excitationEnergyGNP, excitationEnergyDTA,
                      incidentParticle, targetParticle,
                      atomicWeight, atomicNumber);
  if (!successful)
    HighEnergyClusterProduction(successful, pv, vecLength,
                                excitationEnergyGNP, excitationEnergyDTA,
                                incidentParticle, targetParticle,
                                atomicWeight, atomicNumber);
  if (!successful) 
    MediumEnergyCascading(successful, pv, vecLength, 
                          excitationEnergyGNP, excitationEnergyDTA, 
                          incidentParticle, targetParticle,
                          atomicWeight, atomicNumber);
  if (!successful)
    MediumEnergyClusterProduction(successful, pv, vecLength,
                                  excitationEnergyGNP, excitationEnergyDTA,       
                                  incidentParticle, targetParticle,
                                  atomicWeight, atomicNumber);
  if (!successful)
    QuasiElasticScattering(successful, pv, vecLength,
                           excitationEnergyGNP, excitationEnergyDTA,
                           incidentParticle, targetParticle, 
                           atomicWeight, atomicNumber);
  if (!successful)
    ElasticScattering(successful, pv, vecLength,
                      incidentParticle,    
                      atomicWeight, atomicNumber);

  if (!successful) 
    G4cout << "GHEInelasticInteraction::ApplyYourself fails to produce final state particles"
           << G4endl;

  FillParticleChange(pv,  vecLength);
  delete [] pv;
  theParticleChange.SetStatusChange(stopAndKill);
  return &theParticleChange;
}


void
G4HEAntiKaonZeroInelastic::FirstIntInCasAntiKaonZero(G4bool& inElastic,
                                                     const G4double availableEnergy,
                                                     G4HEVector pv[],
                                                     G4int &vecLen,
                                                     const G4HEVector& incidentParticle,
                                                     const G4HEVector& targetParticle)

// AntiKaon0 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.
{
  static const G4double expxu = 82.;      // upper bound for arg. of exp
  static const G4double expxl = -expxu;   // lower bound for arg. of exp

  static const G4double protb = 0.7;
  static const G4double neutb = 0.7;
  static const G4double     c = 1.25;

  static const G4int numMul = 1200;
  static const G4int numSec = 60;

  G4int neutronCode = Neutron.getCode();
  G4int protonCode = Proton.getCode();
  G4int kaonMinusCode = KaonMinus.getCode();
  G4int kaonZeroCode = KaonZero.getCode();
  G4int antiKaonZeroCode = AntiKaonZero.getCode();  

  G4int targetCode = targetParticle.getCode();
  G4double incidentTotalMomentum = incidentParticle.getTotalMomentum();

  static G4bool first = true;
  static G4double protmul[numMul], protnorm[numSec];  // proton constants
  static G4double neutmul[numMul], neutnorm[numSec];  // neutron constants

  // misc. local variables
  // npos = number of pi+,  nneg = number of pi-,  nzero = number of pi0

  G4int i, counter, nt, npos, nneg, nzero;

  if (first) {  // Computation of normalization constants will only be done once
    first = false;
    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,protb,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,neutb,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

  pv[0] = incidentParticle;    // initialize the first two places
  pv[1] = targetParticle;      // the same as beam and target
  vecLen = 2;

  if (!inElastic || (availableEnergy <= PionPlus.getMass())) return;

  // inelastic scattering
  npos = 0, nneg = 0, nzero = 0;
  G4double cech[] = { 1., 1., 1., 0.70, 0.60, 0.55, 0.35, 0.25, 0.18, 0.15};
  G4int iplab = G4int( incidentTotalMomentum*5.);
  if ( (iplab < 10) && (G4UniformRand() < cech[iplab]) ) {
    G4int ipl = std::min(19, G4int( incidentTotalMomentum*5.));
    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[ipl] ) {
      if (targetCode == protonCode) {
        return;
      } else {
        pv[0] = KaonMinus;
        pv[1] = Proton;
        return;
      }
    }

    G4double ran = G4UniformRand();
    if (targetCode == protonCode) {  // target is a proton 
      if (ran < 0.25) { 
      } else if (ran < 0.50) {
        pv[0] = PionPlus;
        pv[1] = SigmaZero;
      } else if (ran < 0.75) {
      } else {
        pv[0] = PionPlus;
        pv[1] = Lambda;
      }
    } else {   // target is a neutron
           if( ran < 0.25 )
             { 
               pv[0] = PionMinus;
               pv[1] = SigmaPlus;
             } 
           else if (ran < 0.50)
             {
               pv[0] = PionZero;
               pv[1] = SigmaZero;
             }
           else if (ran < 0.75)
             { 
               pv[0] = PionPlus;
               pv[1] = SigmaMinus;
             }
           else
             {
               pv[0] = PionZero;
               pv[1] = Lambda;
             }
    }
    return;

  } else {
    // number of total particles vs. centre of mass Energy - 2*proton mass
    G4double aleab = std::log(availableEnergy);
    G4double n = 3.62567+aleab*(0.665843+aleab*(0.336514
                 + aleab*(0.117712+0.0136912*aleab))) - 2.0;
   
    // normalization constant for kno-distribution.
    // calculate first the sum of all constants, check for numerical problems.   
    G4double test, dum, anpn = 0.0;

    for (nt=1; nt<=numSec; nt++) {
      test = std::exp(std::min(expxu, std::max( expxl, -(pi/4.0)*(nt*nt)/(n*n) ) ) );
      dum = pi*nt/(2.0*n*n);
      if (std::fabs(dum) < 1.0) { 
        if( test >= 1.0e-10 )anpn += dum*test;
      } else { 
        anpn += dum*test;
      }
    }
   
    G4double ran = G4UniformRand();
    G4double excs = 0.0;
    if (targetCode == protonCode) {
      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) ) {
                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) goto outOfLoop;      //----------------------->
              }
            }
          }
        }
      }
                                            // 3 previous loops continued to the end
      inElastic = false;                 // quasi-elastic scattering   
      return;

    } else {         // target must be a neutron
         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>=1) && (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) goto outOfLoop;       // -------------------------->
         }
           }
             }
       }
     }
                                                  // 3 previous loops continued to the end
         inElastic = false;                     // quasi-elastic scattering.
         return;
    }
  }  // if (iplab < 10 .... )
 
  outOfLoop:           //  <------------------------------------------------------------------------   
    
  if (targetCode == protonCode) {
    if (npos == nneg) {

    } else if (npos == (1+nneg)) {
      if (G4UniformRand() < 0.5) {
        pv[0] = KaonMinus;
      } else {
        pv[1] = Neutron;
      }
    } else {
      pv[0] = KaonMinus;
      pv[1] = Neutron;
    }

  } else {
      if( npos == nneg)
         {
           if( G4UniformRand() < 0.75)
             {
             }
           else
             {
               pv[0] = KaonMinus;
               pv[1] = Proton;
             }
         } 
       else if ( npos == (1+nneg))
         {
           pv[0] = KaonMinus;
         }
       else
         {
           pv[1] = Proton;
         }
  }      

  if (G4UniformRand() < 0.5) {
    if (((pv[0].getCode() == kaonMinusCode)
          && (pv[1].getCode() == neutronCode) )
        || ((pv[0].getCode() == kaonZeroCode)
             && (pv[1].getCode() == protonCode) )
        || ((pv[0].getCode() == antiKaonZeroCode)
               && (pv[1].getCode() == protonCode) ) ) {

      G4double ran = G4UniformRand();
      if (pv[1].getCode() == protonCode) { 
        if (ran < 0.68) {
          pv[0] = PionPlus;
          pv[1] = Lambda;
        } else if (ran < 0.84) {
          pv[0] = PionZero;
          pv[1] = SigmaPlus;
        } else {
          pv[0] = PionPlus;
          pv[1] = SigmaZero;
        }
      } else {
               if(ran < 0.68)
                 {
                   pv[0] = PionMinus;
                   pv[1] = Lambda;
                 }
               else if (ran < 0.84)
                 {
                   pv[0] = PionMinus;
                   pv[1] = SigmaZero;
                 }
               else
                 {
                   pv[0] = PionZero;
                   pv[1] = SigmaMinus;
                 }
      }
    } else {
           G4double ran = G4UniformRand();
           if (ran < 0.67)
              {
                pv[0] = PionZero;
                pv[1] = Lambda;
              }
           else if (ran < 0.78)
              {
                pv[0] = PionMinus;
                pv[1] = SigmaPlus;
              }
           else if (ran < 0.89)
              {
                pv[0] = PionZero;
                pv[1] = SigmaZero;
              }
           else
              {
                pv[0] = PionPlus;
                pv[1] = SigmaMinus;
              }
    }
  }  // if rand < 0.5
               
  nt = npos + nneg + nzero;
  while (nt > 0) {
    G4double ran = G4UniformRand();
    if (ran < (G4double)npos/nt) { 
      if (npos > 0) {
        pv[vecLen++] = PionPlus;
        npos--;
      }
    } else if (ran < (G4double)(npos+nneg)/nt) {   
      if (nneg > 0) { 
        pv[vecLen++] = PionMinus;
        nneg--;
      }
    } else {
      if (nzero > 0) { 
        pv[vecLen++] = PionZero;
        nzero--;
      }
    }
    nt = npos + nneg + nzero;
  }
 
  if (verboseLevel > 1) {
    G4cout << "Particles produced: " ;
    G4cout << pv[0].getName() << " " ;
    G4cout << pv[1].getName() << " " ;
    for (i=2; i < vecLen; i++) { 
      G4cout << pv[i].getName() << " " ;
    }
    G4cout << G4endl;
  }

  return;
 }