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2 | // ******************************************************************** |
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24 | // ******************************************************************** |
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25 | // |
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26 | // |
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27 | // $Id: G4VElasticCollision.cc,v 1.3 2006/06/29 20:41:53 gunter Exp $ // |
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28 | |
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29 | #include "globals.hh" |
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30 | #include "G4VElasticCollision.hh" |
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31 | #include "G4KineticTrack.hh" |
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32 | #include "G4VCrossSectionSource.hh" |
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33 | #include "G4Proton.hh" |
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34 | #include "G4Neutron.hh" |
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35 | #include "G4XNNElastic.hh" |
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36 | #include "G4AngularDistribution.hh" |
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37 | #include "G4ThreeVector.hh" |
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38 | #include "G4LorentzVector.hh" |
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39 | #include "G4LorentzRotation.hh" |
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40 | #include "G4KineticTrackVector.hh" |
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41 | #include "G4AngularDistributionNP.hh" // np scattering |
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42 | #include "G4AngularDistributionPP.hh" // nn and pp scattering |
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43 | #include <typeinfo> |
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44 | |
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45 | G4VElasticCollision::G4VElasticCollision() |
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46 | { |
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47 | } |
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48 | |
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49 | |
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50 | G4VElasticCollision::~G4VElasticCollision() |
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51 | { } |
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52 | |
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53 | |
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54 | G4KineticTrackVector* G4VElasticCollision::FinalState(const G4KineticTrack& trk1, |
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55 | const G4KineticTrack& trk2) const |
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56 | { |
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57 | const G4VAngularDistribution* angDistribution; |
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58 | |
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59 | angDistribution = GetAngularDistribution(); |
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60 | |
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61 | |
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62 | G4LorentzVector pCM=trk1.Get4Momentum() + trk2.Get4Momentum(); |
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63 | |
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64 | G4LorentzRotation toLabFrame(pCM.boostVector()); |
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65 | G4LorentzVector Ptmp=toLabFrame.inverse() * trk1.Get4Momentum(); //trk1 in CMS |
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66 | G4LorentzRotation toZ; |
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67 | toZ.rotateZ(-Ptmp.phi()); |
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68 | toZ.rotateY(-Ptmp.theta()); |
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69 | toLabFrame *= toZ.inverse(); |
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70 | |
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71 | G4double s = pCM.mag2(); |
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72 | G4double m10 = trk1.GetDefinition()->GetPDGMass(); |
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73 | G4double m20 = trk2.GetDefinition()->GetPDGMass(); |
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74 | if(s-(m10+m20)*(m10+m20) < 0) return new G4KineticTrackVector; |
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75 | |
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76 | G4double m1 = trk1.GetActualMass(); |
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77 | G4double m2 = trk2.GetActualMass(); |
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78 | |
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79 | // Angles of outgoing particles |
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80 | G4double cosTheta = angDistribution->CosTheta(s,m1,m2); |
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81 | |
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82 | if ( (trk1.GetDefinition() == G4Proton::Proton() || trk1.GetDefinition() == G4Neutron::Neutron() ) |
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83 | &&(trk2.GetDefinition() == G4Proton::Proton() || trk2.GetDefinition() == G4Neutron::Neutron() ) ) |
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84 | { |
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85 | if ( trk1.GetDefinition() == trk2.GetDefinition() ) |
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86 | { |
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87 | if ( trk1.GetDefinition() == G4Proton::Proton() ) |
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88 | { |
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89 | // G4cout << "scatterangle pp " << cosTheta |
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90 | // << " " << typeid(*angDistribution).name() << G4endl; |
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91 | } else { |
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92 | // G4cout << "scatterangle nn " << cosTheta |
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93 | // << " " << typeid(*angDistribution).name() << G4endl; |
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94 | } |
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95 | } else { |
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96 | // G4cout << "scatterangle pn " << cosTheta |
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97 | // << " " << typeid(*angDistribution).name() << G4endl; |
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98 | } |
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99 | } else { |
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100 | // G4cout << "scatterangle other " << cosTheta |
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101 | // << " " << typeid(*angDistribution).name() << G4endl; |
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102 | } |
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103 | |
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104 | G4double phi = angDistribution->Phi(); |
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105 | G4double Theta = std::acos(cosTheta); |
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106 | |
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107 | // Unit vector of three-momentum |
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108 | G4ThreeVector pFinal1(std::sin(Theta)*std::cos(phi), std::sin(Theta)*std::sin(phi), cosTheta); |
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109 | // Three momentum in cm system |
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110 | G4double pInCM = std::sqrt((s-(m10+m20)*(m10+m20))*(s-(m10-m20)*(m10-m20))/(4.*s)); |
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111 | pFinal1 = pFinal1 * pInCM; |
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112 | G4ThreeVector pFinal2 = -pFinal1; |
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113 | |
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114 | G4double eFinal1 = std::sqrt(pFinal1.mag2() + m10*m10); |
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115 | G4double eFinal2 = std::sqrt(pFinal2.mag2() + m20*m20); |
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116 | |
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117 | G4LorentzVector p4Final1(pFinal1, eFinal1); |
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118 | G4LorentzVector p4Final2(pFinal2, eFinal2); |
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119 | |
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120 | // Lorentz transformation |
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121 | p4Final1 *= toLabFrame; |
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122 | p4Final2 *= toLabFrame; |
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123 | |
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124 | // Final tracks are copies of incoming ones, with modified 4-momenta |
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125 | G4KineticTrack* final1 = new G4KineticTrack(trk1); |
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126 | final1->Set4Momentum(p4Final1); |
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127 | G4KineticTrack* final2 = new G4KineticTrack(trk2); |
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128 | final2->Set4Momentum(p4Final2); |
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129 | |
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130 | G4KineticTrackVector* finalTracks = new G4KineticTrackVector; |
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131 | finalTracks->push_back(final1); |
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132 | finalTracks->push_back(final2); |
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133 | |
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134 | return finalTracks; |
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135 | } |
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