1 | // |
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2 | // ******************************************************************** |
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3 | // * License and Disclaimer * |
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4 | // * * |
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5 | // * The Geant4 software is copyright of the Copyright Holders of * |
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6 | // * the Geant4 Collaboration. It is provided under the terms and * |
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7 | // * conditions of the Geant4 Software License, included in the file * |
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8 | // * LICENSE and available at http://cern.ch/geant4/license . These * |
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9 | // * include a list of copyright holders. * |
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10 | // * * |
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11 | // * Neither the authors of this software system, nor their employing * |
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12 | // * institutes,nor the agencies providing financial support for this * |
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13 | // * work make any representation or warranty, express or implied, * |
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14 | // * regarding this software system or assume any liability for its * |
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15 | // * use. Please see the license in the file LICENSE and URL above * |
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16 | // * for the full disclaimer and the limitation of liability. * |
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17 | // * * |
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18 | // * This code implementation is the result of the scientific and * |
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19 | // * technical work of the GEANT4 collaboration. * |
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20 | // * By using, copying, modifying or distributing the software (or * |
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21 | // * any work based on the software) you agree to acknowledge its * |
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22 | // * use in resulting scientific publications, and indicate your * |
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23 | // * acceptance of all terms of the Geant4 Software license. * |
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24 | // ******************************************************************** |
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25 | // |
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26 | #include "globals.hh" |
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27 | #include "G4QGSParticipants.hh" |
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28 | #include "G4LorentzVector.hh" |
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29 | #include <utility> |
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30 | |
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31 | // Class G4QGSParticipants |
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32 | |
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33 | // HPW Feb 1999 |
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34 | // Promoting model parameters from local variables class properties |
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35 | G4int G4QGSParticipants_NPart = 0; |
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36 | |
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37 | G4QGSParticipants::G4QGSParticipants() : theDiffExcitaton(), //0.7*GeV, 250*MeV, 250*MeV), |
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38 | //nCutMax(7),ThresholdParameter(0.45*GeV), |
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39 | nCutMax(7),ThresholdParameter(0.000*GeV), |
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40 | QGSMThreshold(3*GeV),theNucleonRadius(1.5*fermi) |
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41 | |
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42 | { |
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43 | } |
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44 | |
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45 | G4QGSParticipants::G4QGSParticipants(const G4QGSParticipants &right) |
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46 | : G4VParticipants(), nCutMax(right.nCutMax),ThresholdParameter(right.ThresholdParameter), |
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47 | QGSMThreshold(right.QGSMThreshold),theNucleonRadius(right.theNucleonRadius) |
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48 | { |
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49 | } |
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50 | |
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51 | |
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52 | G4QGSParticipants::~G4QGSParticipants() |
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53 | { |
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54 | } |
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55 | |
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56 | void G4QGSParticipants::BuildInteractions(const G4ReactionProduct &thePrimary) |
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57 | { |
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58 | |
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59 | // Find the collisions and collition conditions |
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60 | G4VSplitableHadron* aProjectile = SelectInteractions(thePrimary); |
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61 | |
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62 | // now build the parton pairs. HPW |
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63 | SplitHadrons(); |
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64 | |
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65 | // soft collisions first HPW, ordering is vital |
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66 | PerformSoftCollisions(); |
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67 | |
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68 | // the rest is diffractive HPW |
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69 | PerformDiffractiveCollisions(); |
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70 | |
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71 | // clean-up, if necessary |
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72 | std::for_each(theInteractions.begin(), theInteractions.end(), DeleteInteractionContent()); |
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73 | theInteractions.clear(); |
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74 | std::for_each(theTargets.begin(), theTargets.end(), DeleteSplitableHadron()); |
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75 | theTargets.clear(); |
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76 | delete aProjectile; |
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77 | } |
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78 | |
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79 | G4VSplitableHadron* G4QGSParticipants::SelectInteractions(const G4ReactionProduct &thePrimary) |
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80 | { |
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81 | G4VSplitableHadron* aProjectile = new G4QGSMSplitableHadron(thePrimary, TRUE); // @@@ check the TRUE |
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82 | G4PomeronCrossSection theProbability(thePrimary.GetDefinition()); // @@@ should be data member |
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83 | G4double outerRadius = theNucleus->GetOuterRadius(); |
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84 | // Check reaction threshold |
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85 | |
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86 | theNucleus->StartLoop(); |
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87 | G4Nucleon * pNucleon = theNucleus->GetNextNucleon(); |
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88 | G4LorentzVector aPrimaryMomentum(thePrimary.GetMomentum(), thePrimary.GetTotalEnergy()); |
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89 | //--DEBUG--G4cout << " qgspart- " << aPrimaryMomentum << " # " << aPrimaryMomentum.mag() |
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90 | //--DEBUG-- << pNucleon->Get4Momentum() << " # " << (pNucleon->Get4Momentum()).mag()<< G4endl; |
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91 | G4double s = (aPrimaryMomentum + pNucleon->Get4Momentum()).mag2(); |
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92 | G4double ThresholdMass = thePrimary.GetMass() + pNucleon->GetDefinition()->GetPDGMass(); |
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93 | ModelMode = SOFT; |
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94 | if (sqr(ThresholdMass + ThresholdParameter) > s) |
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95 | { |
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96 | ModelMode = DIFFRACTIVE; |
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97 | //throw G4HadronicException(__FILE__, __LINE__, "Initial energy is too low. The 4-vectors of the input are inconsistant with the particle masses."); |
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98 | } |
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99 | if (sqr(ThresholdMass + QGSMThreshold) > s) // thus only diffractive in cascade! |
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100 | { |
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101 | ModelMode = DIFFRACTIVE; |
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102 | } |
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103 | |
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104 | // first find the collisions HPW |
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105 | std::for_each(theInteractions.begin(), theInteractions.end(), DeleteInteractionContent()); |
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106 | theInteractions.clear(); |
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107 | G4int totalCuts = 0; |
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108 | G4double impactUsed = 0; |
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109 | |
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110 | #ifdef debug_QGS |
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111 | G4double eK = thePrimary.GetKineticEnergy()/GeV; |
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112 | #endif |
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113 | #ifdef debug_G4QGSParticipants |
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114 | G4LorentzVector intNuclMom; |
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115 | #endif |
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116 | while(theInteractions.size() == 0) |
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117 | { |
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118 | // choose random impact parameter HPW |
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119 | std::pair<G4double, G4double> theImpactParameter; |
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120 | theImpactParameter = theNucleus->ChooseImpactXandY(outerRadius+theNucleonRadius); |
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121 | G4double impactX = theImpactParameter.first; |
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122 | G4double impactY = theImpactParameter.second; |
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123 | |
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124 | // loop over nuclei to find collissions HPW |
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125 | theNucleus->StartLoop(); |
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126 | G4int nucleonCount = 0; // debug |
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127 | G4QGSParticipants_NPart = 0; |
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128 | #ifdef debug_G4QGSParticipants |
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129 | intNuclMom=aPrimaryMomentum; |
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130 | #endif |
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131 | while( (pNucleon = theNucleus->GetNextNucleon()) ) |
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132 | { |
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133 | if(totalCuts>1.5*thePrimary.GetKineticEnergy()/GeV) |
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134 | { |
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135 | break; |
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136 | } |
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137 | nucleonCount++; // debug |
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138 | // Needs to be moved to Probability class @@@ |
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139 | G4double s = (aPrimaryMomentum + pNucleon->Get4Momentum()).mag2(); |
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140 | G4double Distance2 = sqr(impactX - pNucleon->GetPosition().x()) + |
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141 | sqr(impactY - pNucleon->GetPosition().y()); |
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142 | G4double Probability = theProbability.GetInelasticProbability(s, Distance2); |
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143 | // test for inelastic collision |
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144 | G4double rndNumber = G4UniformRand(); |
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145 | // ModelMode = DIFFRACTIVE; |
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146 | if (Probability > rndNumber) |
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147 | { |
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148 | //--DEBUG-- cout << "DEBUG p="<< Probability<<" r="<<rndNumber<<" d="<<std::sqrt(Distance2)<<G4endl; |
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149 | //--DEBUG-- G4cout << " qgspart+ " << aPrimaryMomentum << " # " << aPrimaryMomentum.mag() |
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150 | //--DEBUG-- << pNucleon->Get4Momentum() << " # " << (pNucleon->Get4Momentum()).mag()<< G4endl; |
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151 | |
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152 | #ifdef debug_G4QGSParticipants |
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153 | intNuclMom += pNucleon->Get4Momentum(); |
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154 | #endif |
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155 | G4QGSMSplitableHadron* aTarget = new G4QGSMSplitableHadron(*pNucleon); |
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156 | G4QGSParticipants_NPart ++; |
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157 | theTargets.push_back(aTarget); |
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158 | pNucleon->Hit(aTarget); |
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159 | if ((theProbability.GetDiffractiveProbability(s, Distance2)/Probability > G4UniformRand() |
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160 | &&(ModelMode==SOFT)) || (ModelMode==DIFFRACTIVE )) |
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161 | { |
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162 | // diffractive interaction occurs |
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163 | if(IsSingleDiffractive()) |
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164 | { |
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165 | theSingleDiffExcitation.ExciteParticipants(aProjectile, aTarget); |
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166 | } |
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167 | else |
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168 | { |
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169 | theDiffExcitaton.ExciteParticipants(aProjectile, aTarget); |
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170 | } |
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171 | G4InteractionContent * aInteraction = new G4InteractionContent(aProjectile); |
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172 | aInteraction->SetTarget(aTarget); |
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173 | theInteractions.push_back(aInteraction); |
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174 | aInteraction->SetNumberOfDiffractiveCollisions(1); |
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175 | totalCuts += 1; |
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176 | } |
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177 | else |
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178 | { |
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179 | // nondiffractive soft interaction occurs |
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180 | // sample nCut+1 (cut Pomerons) pairs of strings can be produced |
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181 | G4int nCut; |
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182 | G4double * running = new G4double[nCutMax]; |
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183 | running[0] = 0; |
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184 | for(nCut = 0; nCut < nCutMax; nCut++) |
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185 | { |
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186 | running[nCut] = theProbability.GetCutPomeronProbability(s, Distance2, nCut + 1); |
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187 | if(nCut!=0) running[nCut] += running[nCut-1]; |
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188 | } |
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189 | G4double random = running[nCutMax-1]*G4UniformRand(); |
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190 | for(nCut = 0; nCut < nCutMax; nCut++) |
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191 | { |
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192 | if(running[nCut] > random) break; |
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193 | } |
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194 | delete [] running; |
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195 | nCut = 0; |
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196 | aTarget->IncrementCollisionCount(nCut+1); |
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197 | aProjectile->IncrementCollisionCount(nCut+1); |
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198 | G4InteractionContent * aInteraction = new G4InteractionContent(aProjectile); |
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199 | aInteraction->SetTarget(aTarget); |
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200 | aInteraction->SetNumberOfSoftCollisions(nCut+1); |
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201 | theInteractions.push_back(aInteraction); |
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202 | totalCuts += nCut+1; |
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203 | impactUsed=Distance2; |
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204 | } |
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205 | } |
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206 | } |
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207 | //--DEBUG-- g4cout << G4endl<<"NUCLEONCOUNT "<<nucleonCount<<G4endl; |
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208 | //--DEBUG-- G4cout << " Interact 4-Vect " << intNuclMom << G4endl; |
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209 | } |
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210 | //--DEBUG-- cout << G4endl<<"CUTDEBUG "<< totalCuts <<G4endl; |
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211 | //--DEBUG-- cout << "Impact Parameter used = "<<impactUsed<<G4endl; |
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212 | return aProjectile; |
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213 | } |
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214 | |
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215 | void G4QGSParticipants::PerformDiffractiveCollisions() |
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216 | { |
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217 | // remove the "G4PartonPair::PROJECTILE", etc., which are not necessary. @@@ |
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218 | unsigned int i; |
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219 | for(i = 0; i < theInteractions.size(); i++) |
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220 | { |
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221 | G4InteractionContent* anIniteraction = theInteractions[i]; |
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222 | G4VSplitableHadron* aProjectile = anIniteraction->GetProjectile(); |
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223 | G4Parton* aParton = aProjectile->GetNextParton(); |
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224 | G4PartonPair * aPartonPair; |
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225 | // projectile first HPW |
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226 | if (aParton) |
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227 | { |
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228 | aPartonPair = new G4PartonPair(aParton, aProjectile->GetNextAntiParton(), |
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229 | G4PartonPair::DIFFRACTIVE, |
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230 | G4PartonPair::PROJECTILE); |
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231 | #ifdef debug_G4QGSPart_PDiffColl |
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232 | G4cout << "DiffPair Pro " << aPartonPair->GetParton1()->GetPDGcode() << " " |
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233 | << aPartonPair->GetParton1()->Get4Momentum() << " " |
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234 | << aPartonPair->GetParton1()->GetX() << " " << G4endl; |
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235 | G4cout << " " << aPartonPair->GetParton2()->GetPDGcode() << " " |
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236 | << aPartonPair->GetParton2()->Get4Momentum() << " " |
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237 | << aPartonPair->GetParton2()->GetX() << " " << G4endl; |
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238 | #endif |
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239 | thePartonPairs.push_back(aPartonPair); |
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240 | } |
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241 | // then target HPW |
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242 | G4VSplitableHadron* aTarget = anIniteraction->GetTarget(); |
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243 | aParton = aTarget->GetNextParton(); |
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244 | if (aParton) |
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245 | { |
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246 | aPartonPair = new G4PartonPair(aParton, aTarget->GetNextAntiParton(), |
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247 | G4PartonPair::DIFFRACTIVE, |
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248 | G4PartonPair::TARGET); |
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249 | #ifdef debug_G4QGSPart_PDiffColl |
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250 | G4cout << "DiffPair Tgt " << aPartonPair->GetParton1()->GetPDGcode() << " " |
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251 | << aPartonPair->GetParton1()->Get4Momentum() << " " |
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252 | << aPartonPair->GetParton1()->GetX() << " " << G4endl; |
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253 | G4cout << " " << aPartonPair->GetParton2()->GetPDGcode() << " " |
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254 | << aPartonPair->GetParton2()->Get4Momentum() << " " |
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255 | << aPartonPair->GetParton2()->GetX() << " " << G4endl; |
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256 | #endif |
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257 | thePartonPairs.push_back(aPartonPair); |
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258 | } |
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259 | } |
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260 | } |
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261 | |
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262 | void G4QGSParticipants::PerformSoftCollisions() |
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263 | { |
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264 | std::vector<G4InteractionContent*>::iterator i; |
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265 | G4LorentzVector str4Mom; |
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266 | i = theInteractions.begin(); |
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267 | while ( i != theInteractions.end() ) |
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268 | { |
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269 | G4InteractionContent* anIniteraction = *i; |
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270 | G4PartonPair * aPair = NULL; |
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271 | if (anIniteraction->GetNumberOfSoftCollisions()) |
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272 | { |
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273 | G4VSplitableHadron* pProjectile = anIniteraction->GetProjectile(); |
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274 | G4VSplitableHadron* pTarget = anIniteraction->GetTarget(); |
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275 | for (G4int j = 0; j < anIniteraction->GetNumberOfSoftCollisions(); j++) |
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276 | { |
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277 | aPair = new G4PartonPair(pTarget->GetNextParton(), pProjectile->GetNextAntiParton(), |
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278 | G4PartonPair::SOFT, G4PartonPair::TARGET); |
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279 | #ifdef debug_G4QGSPart_PSoftColl |
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280 | G4cout << "SoftPair " << aPair->GetParton1()->GetPDGcode() << " " |
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281 | << aPair->GetParton1()->Get4Momentum() << " " |
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282 | << aPair->GetParton1()->GetX() << " " << G4endl; |
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283 | G4cout << " " << aPair->GetParton2()->GetPDGcode() << " " |
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284 | << aPair->GetParton2()->Get4Momentum() << " " |
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285 | << aPair->GetParton2()->GetX() << " " << G4endl; |
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286 | #endif |
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287 | #ifdef debug_G4QGSParticipants |
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288 | str4Mom += aPair->GetParton1()->Get4Momentum(); |
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289 | str4Mom += aPair->GetParton2()->Get4Momentum(); |
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290 | #endif |
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291 | thePartonPairs.push_back(aPair); |
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292 | aPair = new G4PartonPair(pProjectile->GetNextParton(), pTarget->GetNextAntiParton(), |
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293 | G4PartonPair::SOFT, G4PartonPair::PROJECTILE); |
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294 | #ifdef debug_G4QGSPart_PSoftColl |
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295 | G4cout << "SoftPair " << aPair->GetParton1()->GetPDGcode() << " " |
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296 | << aPair->GetParton1()->Get4Momentum() << " " |
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297 | << aPair->GetParton1()->GetX() << " " << G4endl; |
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298 | G4cout << " " << aPair->GetParton2()->GetPDGcode() << " " |
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299 | << aPair->GetParton2()->Get4Momentum() << " " |
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300 | << aPair->GetParton2()->GetX() << " " << G4endl; |
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301 | #endif |
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302 | #ifdef debug_G4QGSParticipants |
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303 | str4Mom += aPair->GetParton1()->Get4Momentum(); |
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304 | str4Mom += aPair->GetParton2()->Get4Momentum(); |
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305 | #endif |
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306 | thePartonPairs.push_back(aPair); |
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307 | } |
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308 | delete *i; |
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309 | i=theInteractions.erase(i); // i now points to the next interaction |
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310 | } else { |
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311 | i++; |
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312 | } |
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313 | } |
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314 | #ifdef debug_G4QGSPart_PSoftColl |
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315 | G4cout << " string 4 mom " << str4Mom << G4endl; |
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316 | #endif |
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317 | } |
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