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G4INCLPiNElasticChannel.cc
Go to the documentation of this file. Or view the newest version in sPHENIX GitHub for file G4INCLPiNElasticChannel.cc
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25 //
26 // INCL++ intra-nuclear cascade model
27 // Alain Boudard, CEA-Saclay, France
28 // Joseph Cugnon, University of Liege, Belgium
29 // Jean-Christophe David, CEA-Saclay, France
30 // Pekka Kaitaniemi, CEA-Saclay, France, and Helsinki Institute of Physics, Finland
31 // Sylvie Leray, CEA-Saclay, France
32 // Davide Mancusi, CEA-Saclay, France
33 //
34 #define INCLXX_IN_GEANT4_MODE 1
35 
36 #include "globals.hh"
37 
39 #include "G4INCLKinematicsUtils.hh"
41 #include "G4INCLRandom.hh"
42 #include "G4INCLGlobals.hh"
43 #include "G4INCLLogger.hh"
44 
45 namespace G4INCL {
46 
48  : particle1(p1), particle2(p2)
49  {
50 
51  }
52 
54 
55  }
56 
58  Particle * nucleon;
59  Particle * pion;
60  if(particle1->isNucleon()) {
61  nucleon = particle1;
62  pion = particle2;
63  } else {
64  nucleon = particle2;
65  pion = particle1;
66  }
67 
68  G4double bpn=8e-6; // B-parameter of exp(Bt) - (MeV/c)^-2
69  G4double px_nucleon=nucleon->getMomentum().getX();
70  G4double py_nucleon=nucleon->getMomentum().getY();
71  G4double pz_nucleon=nucleon->getMomentum().getZ();
72  G4double cnorm1=px_nucleon*px_nucleon+py_nucleon*py_nucleon;
73  G4double cnorm2=std::sqrt(cnorm1);
74  G4double tnorm=cnorm1+pz_nucleon*pz_nucleon;
75  G4double cnorm=std::sqrt(tnorm);
76  G4double btm=std::exp(-4.*tnorm*bpn);
77  G4double rndm=Random::shoot();
78  G4double yrn=1.-rndm*(1.-btm);
79  G4double tt=std::log(yrn)/bpn;
80  G4double ctheta=1.+0.5*tt/tnorm;
81  G4double stheta=std::sqrt(1.-ctheta*ctheta);
82  G4double t7=1.-2.*Random::shoot();
83  G4double t8=std::sqrt(1-t7*t7);
84  G4double t1=-py_nucleon/cnorm2;
85  G4double t2=px_nucleon/cnorm2;
86  G4double t4=t2*pz_nucleon/cnorm;
87  G4double t5=-t1*pz_nucleon/cnorm;
88  G4double t6=-cnorm2/cnorm;
89  ThreeVector mom_nucleon(
90  px_nucleon*ctheta+cnorm*stheta*(t1*t7+t4*t8),
91  py_nucleon*ctheta+cnorm*stheta*(t2*t7+t5*t8),
92  pz_nucleon*ctheta+cnorm*stheta*t6*t8
93  );
94  nucleon->setMomentum(mom_nucleon);
95  pion->setMomentum(-mom_nucleon);
96 
98  if (iso == 1 || iso == -1) {
99  rndm=3*Random::shoot();
100  if (rndm < 1.) {
102  nucleon->setType(nucleonType);
104  pion->setType(pionType);
105  }
106  else {
108  nucleon->setType(nucleonType);
109  pion->setType(PiZero);
110  }
111  }
112  else { // Useless
113  ParticleType nucleonType=ParticleTable::getNucleonType(iso/3);
114  nucleon->setType(nucleonType);
115  ParticleType pionType=ParticleTable::getPionType(2*iso/3);
116  pion->setType(pionType);
117  }
118 
119  fs->addModifiedParticle(nucleon);
120  fs->addModifiedParticle(pion);
121  }
122 
123 }