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G4VElasticCollision.cc
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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 
45 {
46 }
47 
48 
50 { }
51 
52 
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
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 }