| Geant4 Cross Reference |
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25 //
26 //
27
28 #include "globals.hh"
29 #include "G4VElasticCollision.hh"
30 #include "G4KineticTrack.hh"
31 #include "G4VCrossSectionSource.hh"
32 #include "G4Proton.hh"
33 #include "G4Neutron.hh"
34 #include "G4XNNElastic.hh"
35 #include "G4AngularDistribution.hh"
36 #include "G4ThreeVector.hh"
37 #include "G4LorentzVector.hh"
38 #include "G4LorentzRotation.hh"
39 #include "G4KineticTrackVector.hh"
40 #include "G4AngularDistributionNP.hh" // np scattering
41 #include "G4AngularDistributionPP.hh" // nn and pp scattering
42 #include <typeinfo>
43
44 G4VElasticCollision::G4VElasticCollision()
45 {
46 }
47
48
49 G4VElasticCollision::~G4VElasticCollision()
50 { }
51
52
53 G4KineticTrackVector* G4VElasticCollision::FinalState(const G4KineticTrack& trk1,
54 const G4KineticTrack& trk2) const
55 {
56 const G4VAngularDistribution* angDistribution;
57
58 angDistribution = GetAngularDistribution();
59
60
61 G4LorentzVector pCM=trk1.Get4Momentum() + trk2.Get4Momentum();
62
63 G4LorentzRotation toLabFrame(pCM.boostVector());
64 G4LorentzVector Ptmp=toLabFrame.inverse() * trk1.Get4Momentum(); //trk1 in CMS
65 G4LorentzRotation toZ;
66 toZ.rotateZ(-Ptmp.phi());
67 toZ.rotateY(-Ptmp.theta());
68 toLabFrame *= toZ.inverse();
69
70 G4double S = pCM.mag2();
71 G4double m10 = trk1.GetDefinition()->GetPDGMass();
72 G4double m20 = trk2.GetDefinition()->GetPDGMass();
73 if(S-(m10+m20)*(m10+m20) < 0) return new G4KineticTrackVector;
74
75 G4double m_1 = trk1.GetActualMass();
76 G4double m_2 = trk2.GetActualMass();
77
78 // Angles of outgoing particles
79 G4double cosTheta = angDistribution->CosTheta(S,m_1,m_2);
80
81 if ( (trk1.GetDefinition() == G4Proton::Proton() || trk1.GetDefinition() == G4Neutron::Neutron() )
82 &&(trk2.GetDefinition() == G4Proton::Proton() || trk2.GetDefinition() == G4Neutron::Neutron() ) )
83 {
84 if ( trk1.GetDefinition() == trk2.GetDefinition() )
85 {
86 if ( trk1.GetDefinition() == G4Proton::Proton() )
87 {
88 // G4cout << "scatterangle pp " << cosTheta
89 // << " " << typeid(*angDistribution).name() << G4endl;
90 } else {
91 // G4cout << "scatterangle nn " << cosTheta
92 // << " " << typeid(*angDistribution).name() << G4endl;
93 }
94 } else {
95 // G4cout << "scatterangle pn " << cosTheta
96 // << " " << typeid(*angDistribution).name() << G4endl;
97 }
98 } else {
99 // G4cout << "scatterangle other " << cosTheta
100 // << " " << typeid(*angDistribution).name() << G4endl;
101 }
102
103 G4double phi = angDistribution->Phi();
104 G4double Theta = std::acos(cosTheta);
105
106 // Unit vector of three-momentum
107 G4ThreeVector pFinal1(std::sin(Theta)*std::cos(phi), std::sin(Theta)*std::sin(phi), cosTheta);
108 // Three momentum in cm system
109 G4double pInCM = std::sqrt((S-(m10+m20)*(m10+m20))*(S-(m10-m20)*(m10-m20))/(4.*S));
110 pFinal1 = pFinal1 * pInCM;
111 G4ThreeVector pFinal2 = -pFinal1;
112
113 G4double eFinal1 = std::sqrt(pFinal1.mag2() + m10*m10);
114 G4double eFinal2 = std::sqrt(pFinal2.mag2() + m20*m20);
115
116 G4LorentzVector p4Final1(pFinal1, eFinal1);
117 G4LorentzVector p4Final2(pFinal2, eFinal2);
118
119 // Lorentz transformation
120 p4Final1 *= toLabFrame;
121 p4Final2 *= toLabFrame;
122
123 // Final tracks are copies of incoming ones, with modified 4-momenta
124 G4KineticTrack* final1 = new G4KineticTrack(trk1);
125 final1->Set4Momentum(p4Final1);
126 G4KineticTrack* final2 = new G4KineticTrack(trk2);
127 final2->Set4Momentum(p4Final2);
128
129 G4KineticTrackVector* finalTracks = new G4KineticTrackVector;
130 finalTracks->push_back(final1);
131 finalTracks->push_back(final2);
132
133 return finalTracks;
134 }
135