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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
38 #include "G4INCLStrangeAbsorbtionChannel.hh"
39 #include "G4INCLKinematicsUtils.hh"
40 #include "G4INCLBinaryCollisionAvatar.hh"
41 #include "G4INCLRandom.hh"
42 #include "G4INCLGlobals.hh"
43 #include "G4INCLLogger.hh"
44
45 namespace G4INCL {
46
47 StrangeAbsorbtionChannel::StrangeAbsorbtionChannel(Particle *p1, Particle *p2)
48 : particle1(p1), particle2(p2)
49 {
50
51 }
52
53 StrangeAbsorbtionChannel::~StrangeAbsorbtionChannel(){}
54
55 void StrangeAbsorbtionChannel::sampleAngles(G4double *ctet_par, G4double *stet_par, G4double *phi_par) {
56 (*ctet_par) = -1.0 + 2.0*Random::shoot();
57 if(std::abs(*ctet_par) > 1.0) (*ctet_par) = Math::sign(*ctet_par); // needed?
58 (*stet_par) = std::sqrt(1.-(*ctet_par)*(*ctet_par));
59 (*phi_par) = Math::twoPi * Random::shoot();
60 }
61
62 void StrangeAbsorbtionChannel::fillFinalState(FinalState *fs) {
63 Particle * nucleon;
64 Particle * strange;
65
66 ThreeVector const incidentDirection = particle1->getMomentum() + particle2->getMomentum();
67
68 if(particle1->isNucleon()) {
69 nucleon = particle1;
70 strange = particle2;
71 } else {
72 nucleon = particle2;
73 strange = particle1;
74 }
75 // assert(strange->isSigma() || strange->isAntiKaon());
76
77 ParticleType finalType = Neutron;
78 if(ParticleConfig::isPair(nucleon, strange, Neutron, KZeroBar)) {
79 finalType = PiZero;
80 } else if(ParticleConfig::isPair(nucleon, strange, Proton, KZeroBar)) {
81 finalType = PiPlus;
82 } else if(ParticleConfig::isPair(nucleon, strange, Neutron, KMinus)) {
83 finalType = PiMinus;
84 } else if(ParticleConfig::isPair(nucleon, strange, Proton, KMinus)) {
85 finalType = PiZero;
86 } else if(ParticleConfig::isPair(nucleon, strange, Proton, SigmaMinus)) {
87 finalType = Neutron;
88 } else if(ParticleConfig::isPair(nucleon, strange, Neutron, SigmaZero)) {
89 finalType = Neutron;
90 } else if(ParticleConfig::isPair(nucleon, strange, Proton, SigmaZero)) {
91 finalType = Proton;
92 } else if(ParticleConfig::isPair(nucleon, strange, Neutron, SigmaPlus)) {
93 finalType = Proton;
94 } else {
95 INCL_ERROR("Unknown particle pair in Strange-N absorption: " << nucleon << '\t' << strange << '\n');
96 return;
97 }
98
99 G4double energycm = KinematicsUtils::totalEnergyInCM(nucleon, strange);
100
101 G4double finalTypemass = ParticleTable::getINCLMass(finalType);
102 nucleon->setType(Lambda); // nucleon becomes the lambda
103 G4double lambdamass = nucleon->getMass();
104
105 G4double fi, ctet, stet;
106 sampleAngles(&ctet, &stet, &fi);
107
108 G4double cfi = std::cos(fi);
109 G4double sfi = std::sin(fi);
110 G4double beta = incidentDirection.mag();
111
112 G4double q1, q2, q3;
113 G4double sal=0.0;
114 if (beta >= 1.0e-10)
115 sal = incidentDirection.perp()/beta;
116 if (sal >= 1.0e-6) {
117 G4double b1 = incidentDirection.getX();
118 G4double b2 = incidentDirection.getY();
119 G4double b3 = incidentDirection.getZ();
120 G4double cal = b3/beta;
121 G4double t1 = ctet+cal*stet*sfi/sal;
122 G4double t2 = stet/sal;
123 q1=(b1*t1+b2*t2*cfi)/beta;
124 q2=(b2*t1-b1*t2*cfi)/beta;
125 q3=(b3*t1/beta-t2*sfi);
126 } else {
127 q1 = stet*cfi;
128 q2 = stet*sfi;
129 q3 = ctet;
130 }
131
132 G4double xq = KinematicsUtils::momentumInCM(energycm,
133 lambdamass,
134 finalTypemass);
135
136 q1 *= xq;
137 q2 *= xq;
138 q3 *= xq;
139
140 ThreeVector finalMomentum(q1, q2, q3);
141
142 strange->setType(finalType);
143 strange->setMomentum(finalMomentum);
144 strange->adjustEnergyFromMomentum();
145 nucleon->setMomentum(-finalMomentum);
146 nucleon->adjustEnergyFromMomentum();
147
148 fs->addModifiedParticle(nucleon); // nucleon became a lambda
149 fs->addModifiedParticle(strange); // the strange particle became an unstange particle
150 }
151
152 }
153