Gabriele Cosmo
387 lines
12 KiB
C++
387 lines
12 KiB
C++
//
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// ********************************************************************
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// * License and Disclaimer *
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// * *
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// * The Geant4 software is copyright of the Copyright Holders of *
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// * the Geant4 Collaboration. It is provided under the terms and *
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// * conditions of the Geant4 Software License, included in the file *
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// * LICENSE and available at http://cern.ch/geant4/license . These *
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// * include a list of copyright holders. *
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// * *
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// * Neither the authors of this software system, nor their employing *
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// * institutes,nor the agencies providing financial support for this *
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// * work make any representation or warranty, express or implied, *
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// * regarding this software system or assume any liability for its *
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// * use. Please see the license in the file LICENSE and URL above *
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// * for the full disclaimer and the limitation of liability. *
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// * *
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// * This code implementation is the result of the scientific and *
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// * technical work of the GEANT4 collaboration. *
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// * By using, copying, modifying or distributing the software (or *
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// * any work based on the software) you agree to acknowledge its *
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// * use in resulting scientific publications, and indicate your *
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// * acceptance of all terms of the Geant4 Software license. *
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// ********************************************************************
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//
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//
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// Geant4 Header : G4HadronElastic
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//
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// Author : V.Ivanchenko 29 June 2009 (redesign old elastic model)
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//
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#include "G4HadronElastic.hh"
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#include "G4SystemOfUnits.hh"
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#include "G4ParticleTable.hh"
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#include "G4ParticleDefinition.hh"
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#include "G4IonTable.hh"
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#include "Randomize.hh"
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#include "G4Proton.hh"
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#include "G4Neutron.hh"
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#include "G4Deuteron.hh"
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#include "G4Alpha.hh"
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#include "G4Pow.hh"
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#include "G4Exp.hh"
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#include "G4Log.hh"
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#include "G4HadronicParameters.hh"
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#include "G4PhysicsModelCatalog.hh"
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G4HadronElastic::G4HadronElastic(const G4String& name)
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: G4HadronicInteraction(name), secID(-1)
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{
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SetMinEnergy( 0.0*GeV );
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SetMaxEnergy( G4HadronicParameters::Instance()->GetMaxEnergy() );
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lowestEnergyLimit= 1.e-6*eV;
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pLocalTmax = 0.0;
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nwarn = 0;
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theProton = G4Proton::Proton();
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theNeutron = G4Neutron::Neutron();
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theDeuteron = G4Deuteron::Deuteron();
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theAlpha = G4Alpha::Alpha();
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secID = G4PhysicsModelCatalog::GetModelID( "model_" + name );
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}
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G4HadronElastic::~G4HadronElastic()
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{}
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void G4HadronElastic::ModelDescription(std::ostream& outFile) const
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{
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outFile << "G4HadronElastic is the base class for all hadron-nucleus\n"
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<< "elastic scattering models except HP.\n"
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<< "By default it uses the Gheisha two-exponential momentum\n"
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<< "transfer parameterization. The model is fully relativistic\n"
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<< "as opposed to the original Gheisha model which was not.\n"
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<< "This model may be used for all long-lived hadrons at all\n"
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<< "incident energies but fit the data only for relativistic scattering.\n";
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}
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G4HadFinalState* G4HadronElastic::ApplyYourself(
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const G4HadProjectile& aTrack, G4Nucleus& targetNucleus)
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{
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const G4HadProjectile* aParticle = &aTrack;
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G4double ekin = aParticle->GetKineticEnergy();
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// no scattering below the limit
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if(ekin <= lowestEnergyLimit) {
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theParticleChange.SetEnergyChange(ekin);
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theParticleChange.SetMomentumChange(0.,0.,1.);
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return &theParticleChange;
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}
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G4int A = targetNucleus.GetA_asInt();
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G4int Z = targetNucleus.GetZ_asInt();
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// Scattered particle referred to axis of incident particle
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const G4ParticleDefinition* theParticle = aParticle->GetDefinition();
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G4double m1 = theParticle->GetPDGMass();
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G4double plab = std::sqrt(ekin*(ekin + 2.0*m1));
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if (verboseLevel>1) {
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G4cout << "G4HadronElastic: "
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<< aParticle->GetDefinition()->GetParticleName()
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<< " Plab(GeV/c)= " << plab/GeV
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<< " Ekin(MeV) = " << ekin/MeV
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<< " scattered off Z= " << Z
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<< " A= " << A
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<< G4endl;
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}
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G4double mass2 = G4NucleiProperties::GetNuclearMass(A, Z);
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G4double e1 = m1 + ekin;
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G4LorentzVector lv(0.0,0.0,plab,e1+mass2);
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G4ThreeVector bst = lv.boostVector();
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G4double momentumCMS = plab*mass2/std::sqrt(m1*m1 + mass2*mass2 + 2.*mass2*e1);
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pLocalTmax = 4.0*momentumCMS*momentumCMS;
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// Sampling in CM system
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G4double t = SampleInvariantT(theParticle, plab, Z, A);
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if(t < 0.0 || t > pLocalTmax) {
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// For the very rare cases where cos(theta) is greater than 1 or smaller than -1,
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// print some debugging information via a "JustWarning" exception, and resample
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// using the default algorithm
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#ifdef G4VERBOSE
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if(nwarn < 2) {
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G4ExceptionDescription ed;
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ed << GetModelName() << " wrong sampling t= " << t << " tmax= " << pLocalTmax
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<< " for " << aParticle->GetDefinition()->GetParticleName()
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<< " ekin=" << ekin << " MeV"
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<< " off (Z,A)=(" << Z << "," << A << ") - will be resampled" << G4endl;
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G4Exception( "G4HadronElastic::ApplyYourself", "hadEla001", JustWarning, ed);
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++nwarn;
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}
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#endif
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t = G4HadronElastic::SampleInvariantT(theParticle, plab, Z, A);
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}
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G4double phi = G4UniformRand()*CLHEP::twopi;
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G4double cost = 1. - 2.0*t/pLocalTmax;
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// if cos(theta) negative, there is a numerical problem
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// instead of making scattering backward, make in this case
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// no scattering
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if (std::abs(cost) > 1.0) { cost = 1.0; }
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G4double sint = std::sqrt((1.0-cost)*(1.0+cost));
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if (verboseLevel>1) {
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G4cout << " t= " << t << " tmax(GeV^2)= " << pLocalTmax/(GeV*GeV)
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<< " Pcms(GeV)= " << momentumCMS/GeV << " cos(t)=" << cost
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<< " sin(t)=" << sint << G4endl;
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}
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G4LorentzVector nlv1(momentumCMS*sint*std::cos(phi),
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momentumCMS*sint*std::sin(phi),
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momentumCMS*cost,
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std::sqrt(momentumCMS*momentumCMS + m1*m1));
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nlv1.boost(bst);
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G4double eFinal = nlv1.e() - m1;
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if (verboseLevel > 1) {
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G4cout <<"G4HadronElastic: m= " << m1 << " Efin(MeV)= " << eFinal
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<< " 4-M Final: " << nlv1
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<< G4endl;
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}
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if(eFinal <= 0.0) {
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theParticleChange.SetMomentumChange(0.0,0.0,1.0);
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theParticleChange.SetEnergyChange(0.0);
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} else {
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theParticleChange.SetMomentumChange(nlv1.vect().unit());
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theParticleChange.SetEnergyChange(eFinal);
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}
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lv -= nlv1;
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G4double erec = std::max(lv.e() - mass2, 0.0);
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if (verboseLevel > 1) {
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G4cout << "Recoil: " <<" m= " << mass2 << " Erec(MeV)= " << erec
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<< " 4-mom: " << lv
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<< G4endl;
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}
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// the recoil is created if kinetic energy above the threshold
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if(erec > GetRecoilEnergyThreshold()) {
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G4ParticleDefinition * theDef = nullptr;
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if(Z == 1 && A == 1) { theDef = theProton; }
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else if (Z == 1 && A == 2) { theDef = theDeuteron; }
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else if (Z == 1 && A == 3) { theDef = G4Triton::Triton(); }
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else if (Z == 2 && A == 3) { theDef = G4He3::He3(); }
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else if (Z == 2 && A == 4) { theDef = theAlpha; }
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else {
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theDef =
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G4ParticleTable::GetParticleTable()->GetIonTable()->GetIon(Z,A,0.0);
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}
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G4DynamicParticle * aSec = new G4DynamicParticle(theDef, lv.vect().unit(), erec);
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theParticleChange.AddSecondary(aSec, secID);
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} else {
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theParticleChange.SetLocalEnergyDeposit(erec);
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}
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return &theParticleChange;
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}
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// sample momentum transfer in the CMS system
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G4double
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G4HadronElastic::SampleInvariantT(const G4ParticleDefinition* part,
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G4double mom, G4int, G4int A)
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{
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const G4double plabLowLimit = 400.0*CLHEP::MeV;
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const G4double GeV2 = CLHEP::GeV*CLHEP::GeV;
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const G4double z07in13 = std::pow(0.7, 0.3333333333);
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const G4double numLimit = 18.;
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G4int pdg = std::abs(part->GetPDGEncoding());
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G4double tmax = pLocalTmax/GeV2;
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G4double aa, bb, cc, dd;
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G4Pow* g4pow = G4Pow::GetInstance();
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if (A <= 62) {
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if (pdg == 211){ //Pions
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if(mom >= plabLowLimit){ //High energy
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bb = 14.5*g4pow->Z23(A);/*14.5*/
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dd = 10.;
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cc = 0.075*g4pow->Z13(A)/dd;//1.4
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//aa = g4pow->powZ(A, 1.93)/bb;//1.63
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aa = (A*A)/bb;//1.63
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} else { //Low energy
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bb = 29.*z07in13*z07in13*g4pow->Z23(A);
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dd = 15.;
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cc = 0.04*g4pow->Z13(A)/dd;//1.4
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aa = g4pow->powZ(A, 1.63)/bb;//1.63
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}
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} else { //Other particles
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bb = 14.5*g4pow->Z23(A);
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dd = 20.;
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aa = (A*A)/bb;//1.63
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cc = 1.4*g4pow->Z13(A)/dd;
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}
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//===========================
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} else { //(A>62)
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if (pdg == 211) {
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if(mom >= plabLowLimit){ //high
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bb = 60.*z07in13*g4pow->Z13(A);//60
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dd = 30.;
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aa = 0.5*(A*A)/bb;//1.33
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cc = 4.*g4pow->powZ(A,0.4)/dd;//1:0.4 --- 2: 0.4
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} else { //low
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bb = 120.*z07in13*g4pow->Z13(A);//60
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dd = 30.;
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aa = 2.*g4pow->powZ(A,1.33)/bb;
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cc = 4.*g4pow->powZ(A,0.4)/dd;//1:0.4 --- 2: 0.4
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}
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} else {
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bb = 60.*g4pow->Z13(A);
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dd = 25.;
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aa = g4pow->powZ(A,1.33)/bb;//1.33
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cc = 0.2*g4pow->powZ(A,0.4)/dd;//1:0.4 --- 2: 0.4
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}
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}
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G4double q1 = 1.0 - G4Exp(-std::min(bb*tmax, numLimit));
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G4double q2 = 1.0 - G4Exp(-std::min(dd*tmax, numLimit));
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G4double s1 = q1*aa;
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G4double s2 = q2*cc;
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if ((s1 + s2)*G4UniformRand() < s2) {
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q1 = q2;
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bb = dd;
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}
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return -GeV2*G4Log(1.0 - G4UniformRand()*q1)/bb;
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}
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//////////////////////////////////////////////
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//
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// Cofs for s-,c-,b-particles ds/dt slopes
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G4double G4HadronElastic::GetSlopeCof(const G4int pdg )
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{
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// The input parameter "pdg" should be the absolute value of the PDG code
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// (i.e. the same value for a particle and its antiparticle).
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G4double coeff = 1.0;
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// heavy barions
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static const G4double lBarCof1S = 0.88;
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static const G4double lBarCof2S = 0.76;
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static const G4double lBarCof3S = 0.64;
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static const G4double lBarCof1C = 0.784378;
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static const G4double lBarCofSC = 0.664378;
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static const G4double lBarCof2SC = 0.544378;
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static const G4double lBarCof1B = 0.740659;
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static const G4double lBarCofSB = 0.620659;
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static const G4double lBarCof2SB = 0.500659;
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if( pdg == 3122 || pdg == 3222 || pdg == 3112 || pdg == 3212 )
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{
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coeff = lBarCof1S; // Lambda, Sigma+, Sigma-, Sigma0
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} else if( pdg == 3322 || pdg == 3312 )
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{
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coeff = lBarCof2S; // Xi-, Xi0
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}
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else if( pdg == 3324)
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{
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coeff = lBarCof3S; // Omega
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}
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else if( pdg == 4122 || pdg == 4212 || pdg == 4222 || pdg == 4112 )
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{
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coeff = lBarCof1C; // LambdaC+, SigmaC+, SigmaC++, SigmaC0
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}
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else if( pdg == 4332 )
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{
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coeff = lBarCof2SC; // OmegaC
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}
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else if( pdg == 4232 || pdg == 4132 )
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{
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coeff = lBarCofSC; // XiC+, XiC0
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}
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else if( pdg == 5122 || pdg == 5222 || pdg == 5112 || pdg == 5212 )
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{
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coeff = lBarCof1B; // LambdaB, SigmaB+, SigmaB-, SigmaB0
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}
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else if( pdg == 5332 )
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{
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coeff = lBarCof2SB; // OmegaB-
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}
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else if( pdg == 5132 || pdg == 5232 ) // XiB-, XiB0
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{
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coeff = lBarCofSB;
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}
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// heavy mesons Kaons?
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static const G4double lMesCof1S = 0.82; // Kp/piP kaons?
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static const G4double llMesCof1C = 0.676568;
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static const G4double llMesCof1B = 0.610989;
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static const G4double llMesCof2C = 0.353135;
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static const G4double llMesCof2B = 0.221978;
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static const G4double llMesCofSC = 0.496568;
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static const G4double llMesCofSB = 0.430989;
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static const G4double llMesCofCB = 0.287557;
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static const G4double llMesCofEtaP = 0.88;
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static const G4double llMesCofEta = 0.76;
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if( pdg == 321 || pdg == 311 || pdg == 310 )
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{
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coeff = lMesCof1S; //K+-0
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}
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else if( pdg == 511 || pdg == 521 )
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{
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coeff = llMesCof1B; // BMeson0, BMeson+
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}
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else if(pdg == 421 || pdg == 411 )
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{
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coeff = llMesCof1C; // DMeson+, DMeson0
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}
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else if( pdg == 531 )
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{
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coeff = llMesCofSB; // BSMeson0
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}
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else if( pdg == 541 )
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{
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coeff = llMesCofCB; // BCMeson+-
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}
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else if(pdg == 431 )
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{
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coeff = llMesCofSC; // DSMeson+-
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}
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else if(pdg == 441 || pdg == 443 )
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{
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coeff = llMesCof2C; // Etac, JPsi
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}
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else if(pdg == 553 )
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{
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coeff = llMesCof2B; // Upsilon
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}
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else if(pdg == 221 )
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{
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coeff = llMesCofEta; // Eta
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}
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else if(pdg == 331 )
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{
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coeff = llMesCofEtaP; // Eta'
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}
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return coeff;
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}
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