Gabriele Cosmo
136 lines
5.1 KiB
C++
136 lines
5.1 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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// $Id: G4VElasticCollision.cc,v 1.3 2006/06/29 20:41:53 gunter Exp $ //
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#include "globals.hh"
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#include "G4VElasticCollision.hh"
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#include "G4KineticTrack.hh"
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#include "G4VCrossSectionSource.hh"
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#include "G4Proton.hh"
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#include "G4Neutron.hh"
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#include "G4XNNElastic.hh"
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#include "G4AngularDistribution.hh"
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#include "G4ThreeVector.hh"
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#include "G4LorentzVector.hh"
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#include "G4LorentzRotation.hh"
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#include "G4KineticTrackVector.hh"
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#include "G4AngularDistributionNP.hh" // np scattering
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#include "G4AngularDistributionPP.hh" // nn and pp scattering
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#include <typeinfo>
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G4VElasticCollision::G4VElasticCollision()
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{
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}
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G4VElasticCollision::~G4VElasticCollision()
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{ }
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G4KineticTrackVector* G4VElasticCollision::FinalState(const G4KineticTrack& trk1,
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const G4KineticTrack& trk2) const
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{
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const G4VAngularDistribution* angDistribution;
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angDistribution = GetAngularDistribution();
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G4LorentzVector pCM=trk1.Get4Momentum() + trk2.Get4Momentum();
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G4LorentzRotation toLabFrame(pCM.boostVector());
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G4LorentzVector Ptmp=toLabFrame.inverse() * trk1.Get4Momentum(); //trk1 in CMS
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G4LorentzRotation toZ;
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toZ.rotateZ(-Ptmp.phi());
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toZ.rotateY(-Ptmp.theta());
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toLabFrame *= toZ.inverse();
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G4double s = pCM.mag2();
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G4double m10 = trk1.GetDefinition()->GetPDGMass();
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G4double m20 = trk2.GetDefinition()->GetPDGMass();
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if(s-(m10+m20)*(m10+m20) < 0) return new G4KineticTrackVector;
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G4double m1 = trk1.GetActualMass();
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G4double m2 = trk2.GetActualMass();
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// Angles of outgoing particles
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G4double cosTheta = angDistribution->CosTheta(s,m1,m2);
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if ( (trk1.GetDefinition() == G4Proton::Proton() || trk1.GetDefinition() == G4Neutron::Neutron() )
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&&(trk2.GetDefinition() == G4Proton::Proton() || trk2.GetDefinition() == G4Neutron::Neutron() ) )
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{
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if ( trk1.GetDefinition() == trk2.GetDefinition() )
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{
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if ( trk1.GetDefinition() == G4Proton::Proton() )
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{
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// G4cout << "scatterangle pp " << cosTheta
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// << " " << typeid(*angDistribution).name() << G4endl;
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} else {
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// G4cout << "scatterangle nn " << cosTheta
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// << " " << typeid(*angDistribution).name() << G4endl;
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}
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} else {
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// G4cout << "scatterangle pn " << cosTheta
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// << " " << typeid(*angDistribution).name() << G4endl;
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}
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} else {
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// G4cout << "scatterangle other " << cosTheta
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// << " " << typeid(*angDistribution).name() << G4endl;
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}
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G4double phi = angDistribution->Phi();
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G4double Theta = std::acos(cosTheta);
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// Unit vector of three-momentum
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G4ThreeVector pFinal1(std::sin(Theta)*std::cos(phi), std::sin(Theta)*std::sin(phi), cosTheta);
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// Three momentum in cm system
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G4double pInCM = std::sqrt((s-(m10+m20)*(m10+m20))*(s-(m10-m20)*(m10-m20))/(4.*s));
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pFinal1 = pFinal1 * pInCM;
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G4ThreeVector pFinal2 = -pFinal1;
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G4double eFinal1 = std::sqrt(pFinal1.mag2() + m10*m10);
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G4double eFinal2 = std::sqrt(pFinal2.mag2() + m20*m20);
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G4LorentzVector p4Final1(pFinal1, eFinal1);
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G4LorentzVector p4Final2(pFinal2, eFinal2);
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// Lorentz transformation
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p4Final1 *= toLabFrame;
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p4Final2 *= toLabFrame;
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// Final tracks are copies of incoming ones, with modified 4-momenta
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G4KineticTrack* final1 = new G4KineticTrack(trk1);
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final1->Set4Momentum(p4Final1);
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G4KineticTrack* final2 = new G4KineticTrack(trk2);
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final2->Set4Momentum(p4Final2);
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G4KineticTrackVector* finalTracks = new G4KineticTrackVector;
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finalTracks->push_back(final1);
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finalTracks->push_back(final2);
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return finalTracks;
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}
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