Gabriele Cosmo
353 lines
12 KiB
C++
353 lines
12 KiB
C++
// This code implementation is the intellectual property of
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// the RD44 GEANT4 collaboration.
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//
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// By copying, distributing or modifying the Program (or any work
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// based on the Program) you indicate your acceptance of this statement,
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// and all its terms.
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//
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// $Id: G4LEAntiOmegaMinusInelastic.cc,v 1.1 1999/01/07 16:12:44 gunter Exp $
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// GEANT4 tag $Name: geant4-00-01 $
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//
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// Hadronic Process: AntiOmegaMinus Inelastic Process
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// J.L. Chuma, TRIUMF, 20-Feb-1997
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// Last modified: 27-Mar-1997
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// Modified by J.L.Chuma 30-Apr-97: added originalTarget for CalculateMomenta
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//
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// NOTE: The FORTRAN version of the cascade, CASAOM, simply called the
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// routine for the OmegaMinus particle. Hence, the Cascade function
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// below is just a copy of the Cascade from the OmegaMinus particle.
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#include "G4LEAntiOmegaMinusInelastic.hh"
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#include "Randomize.hh"
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G4VParticleChange *
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G4LEAntiOmegaMinusInelastic::ApplyYourself( const G4Track &aTrack,
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G4Nucleus &targetNucleus )
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{
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theParticleChange.Initialize( aTrack );
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const G4DynamicParticle *originalIncident = aTrack.GetDynamicParticle();
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if (originalIncident->GetKineticEnergy()<= 0.1*MeV) return &theParticleChange;
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//
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// create the target particle
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//
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G4DynamicParticle *originalTarget = targetNucleus.ReturnTargetParticle();
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if( verboseLevel > 1 )
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{
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G4Material *targetMaterial = aTrack.GetMaterial();
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G4cout << "kinetic energy = " << originalIncident->GetKineticEnergy()/MeV << "MeV, ";
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G4cout << "target material = " << targetMaterial->GetName() << ", ";
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G4cout << "target particle = " << originalTarget->GetDefinition()->GetParticleName()
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<< endl;
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}
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//
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// Fermi motion and evaporation
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// As of Geant3, the Fermi energy calculation had not been Done
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//
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G4double ek = originalIncident->GetKineticEnergy()/MeV;
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G4double amas = originalIncident->GetDefinition()->GetPDGMass()/MeV;
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G4ReactionProduct modifiedOriginal;
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modifiedOriginal = *originalIncident;
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G4double tkin = targetNucleus.Cinema( ek );
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ek += tkin;
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modifiedOriginal.SetKineticEnergy( ek*MeV );
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G4double et = ek + amas;
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G4double p = sqrt( abs((et-amas)*(et+amas)) );
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G4double pp = modifiedOriginal.GetMomentum().mag()/MeV;
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if( pp > 0.0 )
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{
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G4ThreeVector momentum = modifiedOriginal.GetMomentum();
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modifiedOriginal.SetMomentum( momentum * (p/pp) );
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}
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//
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// calculate black track energies
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//
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tkin = targetNucleus.EvaporationEffects( ek );
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ek -= tkin;
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modifiedOriginal.SetKineticEnergy( ek*MeV );
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et = ek + amas;
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p = sqrt( abs((et-amas)*(et+amas)) );
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pp = modifiedOriginal.GetMomentum().mag()/MeV;
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if( pp > 0.0 )
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{
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G4ThreeVector momentum = modifiedOriginal.GetMomentum();
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modifiedOriginal.SetMomentum( momentum * (p/pp) );
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}
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G4ReactionProduct currentParticle = modifiedOriginal;
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G4ReactionProduct targetParticle;
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targetParticle = *originalTarget;
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currentParticle.SetSide( 1 ); // incident always goes in forward hemisphere
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targetParticle.SetSide( -1 ); // target always goes in backward hemisphere
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G4bool incidentHasChanged = false;
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G4bool targetHasChanged = false;
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G4bool quasiElastic = false;
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G4FastVector<G4ReactionProduct,128> vec; // vec will contain the secondary particles
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G4int vecLen = 0;
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vec.Initialize( 0 );
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const G4double cutOff = 0.1;
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const G4double anni = min( 1.3*currentParticle.GetTotalMomentum()/GeV, 0.4 );
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if( (currentParticle.GetKineticEnergy()/MeV > cutOff) || (G4UniformRand() > anni) )
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Cascade( vec, vecLen,
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originalIncident, currentParticle, targetParticle,
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incidentHasChanged, targetHasChanged, quasiElastic );
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CalculateMomenta( vec, vecLen,
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originalIncident, originalTarget, modifiedOriginal,
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targetNucleus, currentParticle, targetParticle,
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incidentHasChanged, targetHasChanged, quasiElastic );
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SetUpChange( vec, vecLen,
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currentParticle, targetParticle,
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incidentHasChanged );
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delete originalTarget;
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return &theParticleChange;
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}
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void
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G4LEAntiOmegaMinusInelastic::Cascade(
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G4FastVector<G4ReactionProduct,128> &vec,
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G4int& vecLen,
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const G4DynamicParticle *originalIncident,
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G4ReactionProduct ¤tParticle,
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G4ReactionProduct &targetParticle,
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G4bool &incidentHasChanged,
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G4bool &targetHasChanged,
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G4bool &quasiElastic )
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{
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// derived from original FORTRAN code CASOM by H. Fesefeldt (31-Jan-1989)
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//
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// AntiOmegaMinus undergoes interaction with nucleon within a nucleus. Check if it is
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// energetically possible to produce pions/kaons. In not, assume nuclear excitation
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// occurs and input particle is degraded in energy. No other particles are produced.
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// If reaction is possible, find the correct number of pions/protons/neutrons
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// produced using an interpolation to multiplicity data. Replace some pions or
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// protons/neutrons by kaons or strange baryons according to the average
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// multiplicity per Inelastic reaction.
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//
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const G4double mOriginal = originalIncident->GetDefinition()->GetPDGMass()/MeV;
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const G4double etOriginal = originalIncident->GetTotalEnergy()/MeV;
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const G4double pOriginal = originalIncident->GetTotalMomentum()/MeV;
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const G4double targetMass = targetParticle.GetMass()/MeV;
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G4double centerofmassEnergy = sqrt( mOriginal*mOriginal +
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targetMass*targetMass +
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2.0*targetMass*etOriginal );
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G4double availableEnergy = centerofmassEnergy-(targetMass+mOriginal);
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if( availableEnergy <= G4PionPlus::PionPlus()->GetPDGMass()/MeV )
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{ // not energetically possible to produce pion(s)
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quasiElastic = true;
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return;
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}
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static G4bool first = true;
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const G4int numMul = 1200;
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const G4int numSec = 60;
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static G4double protmul[numMul], protnorm[numSec]; // proton constants
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static G4double neutmul[numMul], neutnorm[numSec]; // neutron constants
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// np = number of pi+, nm = number of pi-, nz = number of pi0
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G4int counter, nt=0, np=0, nm=0, nz=0;
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G4double test;
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const G4double c = 1.25;
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const G4double b[] = { 0.7, 0.7 };
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if( first ) // compute normalization constants, this will only be Done once
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{
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first = false;
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G4int i;
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for( i=0; i<numMul; ++i )protmul[i] = 0.0;
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for( i=0; i<numSec; ++i )protnorm[i] = 0.0;
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counter = -1;
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for( np=0; np<(numSec/3); ++np )
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{
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for( nm=max(0,np-1); nm<=(np+1); ++nm )
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{
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for( nz=0; nz<numSec/3; ++nz )
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{
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if( ++counter < numMul )
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{
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nt = np+nm+nz;
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if( nt>0 && nt<=numSec )
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{
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protmul[counter] = Pmltpc(np,nm,nz,nt,b[0],c);
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protnorm[nt-1] += protmul[counter];
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}
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}
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}
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}
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}
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for( i=0; i<numMul; ++i )neutmul[i] = 0.0;
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for( i=0; i<numSec; ++i )neutnorm[i] = 0.0;
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counter = -1;
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for( np=0; np<numSec/3; ++np )
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{
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for( nm=np; nm<=(np+2); ++nm )
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{
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for( nz=0; nz<numSec/3; ++nz )
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{
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if( ++counter < numMul )
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{
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nt = np+nm+nz;
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if( nt>0 && nt<=numSec )
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{
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neutmul[counter] = Pmltpc(np,nm,nz,nt,b[1],c);
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neutnorm[nt-1] += neutmul[counter];
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}
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}
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}
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}
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}
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for( i=0; i<numSec; ++i )
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{
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if( protnorm[i] > 0.0 )protnorm[i] = 1.0/protnorm[i];
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if( neutnorm[i] > 0.0 )neutnorm[i] = 1.0/neutnorm[i];
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}
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} // end of initialization
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const G4double expxu = 82.; // upper bound for arg. of exp
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const G4double expxl = -expxu; // lower bound for arg. of exp
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G4ParticleDefinition *aNeutron = G4Neutron::Neutron();
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G4ParticleDefinition *aProton = G4Proton::Proton();
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G4ParticleDefinition *aKaonMinus = G4KaonMinus::KaonMinus();
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G4ParticleDefinition *aSigmaPlus = G4SigmaPlus::SigmaPlus();
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G4ParticleDefinition *aXiZero = G4XiZero::XiZero();
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G4double n, anpn;
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GetNormalizationConstant( availableEnergy, n, anpn );
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G4double ran = G4UniformRand();
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G4double dum, excs = 0.0;
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G4int nvefix = 0;
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if( targetParticle.GetDefinition() == aProton )
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{
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counter = -1;
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for( np=0; np<numSec/3 && ran>=excs; ++np )
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{
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for( nm=max(0,np-1); nm<=(np+1) && ran>=excs; ++nm )
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{
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for( nz=0; nz<numSec/3 && ran>=excs; ++nz )
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{
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if( ++counter < numMul )
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{
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nt = np+nm+nz;
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if( nt>0 && nt<=numSec )
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{
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test = exp( min( expxu, max( expxl, -(pi/4.0)*(nt*nt)/(n*n) ) ) );
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dum = (pi/anpn)*nt*protmul[counter]*protnorm[nt-1]/(2.0*n*n);
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if( fabs(dum) < 1.0 )
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{
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if( test >= 1.0e-10 )excs += dum*test;
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}
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else
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excs += dum*test;
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}
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}
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}
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}
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}
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if( ran >= excs ) // 3 previous loops continued to the end
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{
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quasiElastic = true;
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return;
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}
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np--; nm--; nz--;
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//
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// number of secondary mesons determined by kno distribution
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// check for total charge of final state mesons to determine
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// the kind of baryons to be produced, taking into account
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// charge and strangeness conservation
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//
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if( np < nm )
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{
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if( np+1 == nm )
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{
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currentParticle.SetDefinitionAndUpdateE( aXiZero );
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incidentHasChanged = true;
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nvefix = 1;
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}
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else // charge mismatch
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{
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currentParticle.SetDefinitionAndUpdateE( aSigmaPlus );
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incidentHasChanged = true;
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nvefix = 2;
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}
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}
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else if( np > nm )
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{
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targetParticle.SetDefinitionAndUpdateE( aNeutron );
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targetHasChanged = true;
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}
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}
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else // target must be a neutron
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{
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counter = -1;
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for( np=0; np<numSec/3 && ran>=excs; ++np )
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{
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for( nm=np; nm<=(np+2) && ran>=excs; ++nm )
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{
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for( nz=0; nz<numSec/3 && ran>=excs; ++nz )
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{
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if( ++counter < numMul )
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{
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nt = np+nm+nz;
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if( nt>0 && nt<=numSec )
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{
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test = exp( min( expxu, max( expxl, -(pi/4.0)*(nt*nt)/(n*n) ) ) );
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dum = (pi/anpn)*nt*neutmul[counter]*neutnorm[nt-1]/(2.0*n*n);
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if( fabs(dum) < 1.0 )
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{
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if( test >= 1.0e-10 )excs += dum*test;
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}
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else
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excs += dum*test;
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}
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}
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}
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}
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}
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if( ran >= excs ) // 3 previous loops continued to the end
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{
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quasiElastic = true;
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return;
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}
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np--; nm--; nz--;
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if( np+1 < nm )
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{
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if( np+2 == nm )
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{
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currentParticle.SetDefinitionAndUpdateE( aXiZero );
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incidentHasChanged = true;
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nvefix = 1;
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}
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else // charge mismatch
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{
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currentParticle.SetDefinitionAndUpdateE( aSigmaPlus );
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incidentHasChanged = true;
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nvefix = 2;
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}
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targetParticle.SetDefinitionAndUpdateE( aProton );
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targetHasChanged = true;
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}
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else if( np+1 == nm )
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{
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targetParticle.SetDefinitionAndUpdateE( aProton );
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targetHasChanged = true;
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}
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}
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SetUpPions( np, nm, nz, vec, vecLen );
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for( G4int i=0; i<vecLen && nvefix>0; ++i )
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{
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if( vec[i]->GetDefinition() == G4PionMinus::PionMinus() )
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{
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//
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// correct the strangeness by replacing a pi- by a kaon-
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//
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if( nvefix >= 1 )vec[i]->SetDefinitionAndUpdateE( aKaonMinus );
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--nvefix;
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}
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}
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return;
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}
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/* end of file */
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