1 | // |
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2 | // ******************************************************************** |
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3 | // * License and Disclaimer * |
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4 | // * * |
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6 | // * the Geant4 Collaboration. It is provided under the terms and * |
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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 | // |
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27 | // $Id: G4LEXiMinusInelastic.cc,v 1.11 2006/06/29 20:45:23 gunter Exp $ |
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28 | // GEANT4 tag $Name: geant4-09-02 $ |
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29 | // |
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30 | // Hadronic Process: XiMinus Inelastic Process |
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31 | // J.L. Chuma, TRIUMF, 20-Feb-1997 |
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32 | // Last modified: 27-Mar-1997 |
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33 | // Modified by J.L.Chuma 30-Apr-97: added originalTarget for CalculateMomenta |
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34 | |
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35 | #include "G4LEXiMinusInelastic.hh" |
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36 | #include "Randomize.hh" |
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37 | |
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38 | G4HadFinalState * |
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39 | G4LEXiMinusInelastic::ApplyYourself( const G4HadProjectile &aTrack, |
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40 | G4Nucleus &targetNucleus ) |
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41 | { |
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42 | const G4HadProjectile *originalIncident = &aTrack; |
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43 | if (originalIncident->GetKineticEnergy()<= 0.1*MeV) |
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44 | { |
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45 | theParticleChange.SetStatusChange(isAlive); |
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46 | theParticleChange.SetEnergyChange(aTrack.GetKineticEnergy()); |
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47 | theParticleChange.SetMomentumChange(aTrack.Get4Momentum().vect().unit()); |
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48 | return &theParticleChange; |
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49 | } |
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50 | // |
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51 | // create the target particle |
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52 | // |
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53 | G4DynamicParticle *originalTarget = targetNucleus.ReturnTargetParticle(); |
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54 | |
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55 | if( verboseLevel > 1 ) |
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56 | { |
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57 | const G4Material *targetMaterial = aTrack.GetMaterial(); |
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58 | G4cout << "G4LEXiMinusInelastic::ApplyYourself called" << G4endl; |
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59 | G4cout << "kinetic energy = " << originalIncident->GetKineticEnergy()/MeV << "MeV, "; |
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60 | G4cout << "target material = " << targetMaterial->GetName() << ", "; |
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61 | G4cout << "target particle = " << originalTarget->GetDefinition()->GetParticleName() |
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62 | << G4endl; |
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63 | } |
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64 | // |
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65 | // Fermi motion and evaporation |
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66 | // As of Geant3, the Fermi energy calculation had not been Done |
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67 | // |
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68 | G4double ek = originalIncident->GetKineticEnergy()/MeV; |
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69 | G4double amas = originalIncident->GetDefinition()->GetPDGMass()/MeV; |
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70 | G4ReactionProduct modifiedOriginal; |
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71 | modifiedOriginal = *originalIncident; |
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72 | |
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73 | G4double tkin = targetNucleus.Cinema( ek ); |
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74 | ek += tkin; |
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75 | modifiedOriginal.SetKineticEnergy( ek*MeV ); |
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76 | G4double et = ek + amas; |
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77 | G4double p = std::sqrt( std::abs((et-amas)*(et+amas)) ); |
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78 | G4double pp = modifiedOriginal.GetMomentum().mag()/MeV; |
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79 | if( pp > 0.0 ) |
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80 | { |
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81 | G4ThreeVector momentum = modifiedOriginal.GetMomentum(); |
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82 | modifiedOriginal.SetMomentum( momentum * (p/pp) ); |
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83 | } |
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84 | // |
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85 | // calculate black track energies |
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86 | // |
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87 | tkin = targetNucleus.EvaporationEffects( ek ); |
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88 | ek -= tkin; |
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89 | modifiedOriginal.SetKineticEnergy( ek*MeV ); |
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90 | et = ek + amas; |
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91 | p = std::sqrt( std::abs((et-amas)*(et+amas)) ); |
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92 | pp = modifiedOriginal.GetMomentum().mag()/MeV; |
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93 | if( pp > 0.0 ) |
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94 | { |
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95 | G4ThreeVector momentum = modifiedOriginal.GetMomentum(); |
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96 | modifiedOriginal.SetMomentum( momentum * (p/pp) ); |
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97 | } |
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98 | G4ReactionProduct currentParticle = modifiedOriginal; |
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99 | G4ReactionProduct targetParticle; |
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100 | targetParticle = *originalTarget; |
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101 | currentParticle.SetSide( 1 ); // incident always goes in forward hemisphere |
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102 | targetParticle.SetSide( -1 ); // target always goes in backward hemisphere |
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103 | G4bool incidentHasChanged = false; |
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104 | G4bool targetHasChanged = false; |
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105 | G4bool quasiElastic = false; |
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106 | G4FastVector<G4ReactionProduct,GHADLISTSIZE> vec; // vec will contain the secondary particles |
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107 | G4int vecLen = 0; |
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108 | vec.Initialize( 0 ); |
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109 | |
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110 | const G4double cutOff = 0.1; |
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111 | if( currentParticle.GetKineticEnergy()/MeV > cutOff ) |
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112 | Cascade( vec, vecLen, |
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113 | originalIncident, currentParticle, targetParticle, |
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114 | incidentHasChanged, targetHasChanged, quasiElastic ); |
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115 | |
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116 | CalculateMomenta( vec, vecLen, |
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117 | originalIncident, originalTarget, modifiedOriginal, |
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118 | targetNucleus, currentParticle, targetParticle, |
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119 | incidentHasChanged, targetHasChanged, quasiElastic ); |
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120 | |
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121 | SetUpChange( vec, vecLen, |
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122 | currentParticle, targetParticle, |
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123 | incidentHasChanged ); |
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124 | |
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125 | delete originalTarget; |
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126 | return &theParticleChange; |
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127 | } |
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128 | |
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129 | void |
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130 | G4LEXiMinusInelastic::Cascade( |
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131 | G4FastVector<G4ReactionProduct,GHADLISTSIZE> &vec, |
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132 | G4int& vecLen, |
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133 | const G4HadProjectile *originalIncident, |
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134 | G4ReactionProduct ¤tParticle, |
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135 | G4ReactionProduct &targetParticle, |
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136 | G4bool &incidentHasChanged, |
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137 | G4bool &targetHasChanged, |
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138 | G4bool &quasiElastic ) |
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139 | { |
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140 | // derived from original FORTRAN code CASXM by H. Fesefeldt (17-Jan-1989) |
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141 | // |
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142 | // XiMinus undergoes interaction with nucleon within a nucleus. Check if it is |
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143 | // energetically possible to produce pions/kaons. In not, assume nuclear excitation |
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144 | // occurs and input particle is degraded in energy. No other particles are produced. |
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145 | // If reaction is possible, find the correct number of pions/protons/neutrons |
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146 | // produced using an interpolation to multiplicity data. Replace some pions or |
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147 | // protons/neutrons by kaons or strange baryons according to the average |
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148 | // multiplicity per inelastic reaction. |
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149 | // |
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150 | const G4double mOriginal = originalIncident->GetDefinition()->GetPDGMass()/MeV; |
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151 | const G4double etOriginal = originalIncident->GetTotalEnergy()/MeV; |
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152 | const G4double targetMass = targetParticle.GetMass()/MeV; |
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153 | G4double centerofmassEnergy = std::sqrt( mOriginal*mOriginal + |
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154 | targetMass*targetMass + |
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155 | 2.0*targetMass*etOriginal ); |
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156 | G4double availableEnergy = centerofmassEnergy-(targetMass+mOriginal); |
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157 | if( availableEnergy <= G4PionPlus::PionPlus()->GetPDGMass()/MeV ) |
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158 | { |
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159 | quasiElastic = true; |
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160 | return; |
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161 | } |
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162 | static G4bool first = true; |
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163 | const G4int numMul = 1200; |
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164 | const G4int numSec = 60; |
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165 | static G4double protmul[numMul], protnorm[numSec]; // proton constants |
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166 | static G4double neutmul[numMul], neutnorm[numSec]; // neutron constants |
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167 | // np = number of pi+, nm = number of pi-, nz = number of pi0 |
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168 | G4int counter, nt=0, np=0, nm=0, nz=0; |
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169 | G4double test; |
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170 | const G4double c = 1.25; |
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171 | const G4double b[] = { 0.7, 0.7 }; |
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172 | if( first ) // compute normalization constants, this will only be Done once |
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173 | { |
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174 | first = false; |
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175 | G4int i; |
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176 | for( i=0; i<numMul; ++i )protmul[i] = 0.0; |
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177 | for( i=0; i<numSec; ++i )protnorm[i] = 0.0; |
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178 | counter = -1; |
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179 | for( np=0; np<(numSec/3); ++np ) |
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180 | { |
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181 | for( nm=std::max(0,np-1); nm<=(np+1); ++nm ) |
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182 | { |
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183 | for( nz=0; nz<numSec/3; ++nz ) |
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184 | { |
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185 | if( ++counter < numMul ) |
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186 | { |
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187 | nt = np+nm+nz; |
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188 | if( nt>0 && nt<=numSec ) |
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189 | { |
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190 | protmul[counter] = Pmltpc(np,nm,nz,nt,b[0],c); |
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191 | protnorm[nt-1] += protmul[counter]; |
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192 | } |
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193 | } |
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194 | } |
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195 | } |
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196 | } |
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197 | for( i=0; i<numMul; ++i )neutmul[i] = 0.0; |
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198 | for( i=0; i<numSec; ++i )neutnorm[i] = 0.0; |
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199 | counter = -1; |
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200 | for( np=0; np<numSec/3; ++np ) |
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201 | { |
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202 | for( nm=np; nm<=(np+2); ++nm ) |
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203 | { |
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204 | for( nz=0; nz<numSec/3; ++nz ) |
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205 | { |
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206 | if( ++counter < numMul ) |
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207 | { |
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208 | nt = np+nm+nz; |
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209 | if( nt>0 && nt<=numSec ) |
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210 | { |
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211 | neutmul[counter] = Pmltpc(np,nm,nz,nt,b[1],c); |
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212 | neutnorm[nt-1] += neutmul[counter]; |
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213 | } |
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214 | } |
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215 | } |
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216 | } |
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217 | } |
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218 | for( i=0; i<numSec; ++i ) |
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219 | { |
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220 | if( protnorm[i] > 0.0 )protnorm[i] = 1.0/protnorm[i]; |
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221 | if( neutnorm[i] > 0.0 )neutnorm[i] = 1.0/neutnorm[i]; |
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222 | } |
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223 | } // end of initialization |
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224 | |
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225 | const G4double expxu = 82.; // upper bound for arg. of exp |
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226 | const G4double expxl = -expxu; // lower bound for arg. of exp |
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227 | G4ParticleDefinition *aNeutron = G4Neutron::Neutron(); |
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228 | G4ParticleDefinition *aProton = G4Proton::Proton(); |
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229 | G4ParticleDefinition *aKaonMinus = G4KaonMinus::KaonMinus(); |
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230 | G4ParticleDefinition *aSigmaPlus = G4SigmaPlus::SigmaPlus(); |
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231 | G4ParticleDefinition *aXiZero = G4XiZero::XiZero(); |
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232 | // |
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233 | // energetically possible to produce pion(s) --> inelastic scattering |
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234 | // |
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235 | G4double n, anpn; |
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236 | GetNormalizationConstant( availableEnergy, n, anpn ); |
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237 | G4double ran = G4UniformRand(); |
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238 | G4double dum, excs = 0.0; |
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239 | if( targetParticle.GetDefinition() == aProton ) |
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240 | { |
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241 | counter = -1; |
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242 | for( np=0; np<numSec/3 && ran>=excs; ++np ) |
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243 | { |
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244 | for( nm=std::max(0,np-1); nm<=(np+1) && ran>=excs; ++nm ) |
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245 | { |
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246 | for( nz=0; nz<numSec/3 && ran>=excs; ++nz ) |
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247 | { |
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248 | if( ++counter < numMul ) |
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249 | { |
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250 | nt = np+nm+nz; |
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251 | if( nt>0 && nt<=numSec ) |
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252 | { |
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253 | test = std::exp( std::min( expxu, std::max( expxl, -(pi/4.0)*(nt*nt)/(n*n) ) ) ); |
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254 | dum = (pi/anpn)*nt*protmul[counter]*protnorm[nt-1]/(2.0*n*n); |
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255 | if( std::fabs(dum) < 1.0 ) |
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256 | { |
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257 | if( test >= 1.0e-10 )excs += dum*test; |
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258 | } |
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259 | else |
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260 | excs += dum*test; |
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261 | } |
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262 | } |
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263 | } |
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264 | } |
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265 | } |
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266 | if( ran >= excs ) // 3 previous loops continued to the end |
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267 | { |
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268 | quasiElastic = true; |
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269 | return; |
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270 | } |
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271 | np--; nm--; nz--; |
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272 | // |
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273 | // number of secondary mesons determined by kno distribution |
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274 | // check for total charge of final state mesons to determine |
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275 | // the kind of baryons to be produced, taking into account |
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276 | // charge and strangeness conservation |
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277 | // |
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278 | if( np < nm ) |
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279 | { |
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280 | if( np+1 == nm ) |
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281 | { |
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282 | currentParticle.SetDefinitionAndUpdateE( aXiZero ); |
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283 | incidentHasChanged = true; |
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284 | } |
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285 | else // charge mismatch |
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286 | { |
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287 | currentParticle.SetDefinitionAndUpdateE( aSigmaPlus ); |
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288 | incidentHasChanged = true; |
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289 | // |
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290 | // correct the strangeness by replacing a pi- by a kaon- |
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291 | // |
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292 | vec.Initialize( 1 ); |
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293 | G4ReactionProduct *p = new G4ReactionProduct; |
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294 | p->SetDefinition( aKaonMinus ); |
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295 | (G4UniformRand() < 0.5) ? p->SetSide( -1 ) : p->SetSide( 1 ); |
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296 | vec.SetElement( vecLen++, p ); |
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297 | --nm; |
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298 | } |
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299 | } |
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300 | else if( np == nm ) |
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301 | { |
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302 | if( G4UniformRand() >= 0.5 ) |
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303 | { |
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304 | currentParticle.SetDefinitionAndUpdateE( aXiZero ); |
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305 | incidentHasChanged = true; |
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306 | targetParticle.SetDefinitionAndUpdateE( aNeutron ); |
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307 | targetHasChanged = true; |
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308 | } |
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309 | } |
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310 | else |
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311 | { |
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312 | targetParticle.SetDefinitionAndUpdateE( aNeutron ); |
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313 | targetHasChanged = true; |
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314 | } |
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315 | } |
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316 | else // target must be a neutron |
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317 | { |
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318 | counter = -1; |
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319 | for( np=0; np<numSec/3 && ran>=excs; ++np ) |
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320 | { |
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321 | for( nm=np; nm<=(np+2) && ran>=excs; ++nm ) |
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322 | { |
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323 | for( nz=0; nz<numSec/3 && ran>=excs; ++nz ) |
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324 | { |
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325 | if( ++counter < numMul ) |
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326 | { |
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327 | nt = np+nm+nz; |
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328 | if( nt>0 && nt<=numSec ) |
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329 | { |
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330 | test = std::exp( std::min( expxu, std::max( expxl, -(pi/4.0)*(nt*nt)/(n*n) ) ) ); |
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331 | dum = (pi/anpn)*nt*neutmul[counter]*neutnorm[nt-1]/(2.0*n*n); |
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332 | if( std::fabs(dum) < 1.0 ) |
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333 | { |
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334 | if( test >= 1.0e-10 )excs += dum*test; |
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335 | } |
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336 | else |
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337 | excs += dum*test; |
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338 | } |
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339 | } |
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340 | } |
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341 | } |
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342 | } |
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343 | if( ran >= excs ) // 3 previous loops continued to the end |
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344 | { |
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345 | quasiElastic = true; |
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346 | return; |
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347 | } |
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348 | np--; nm--; nz--; |
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349 | if( np+1 < nm ) |
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350 | { |
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351 | if( np+2 == nm ) |
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352 | { |
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353 | currentParticle.SetDefinitionAndUpdateE( aXiZero ); |
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354 | incidentHasChanged = true; |
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355 | targetParticle.SetDefinitionAndUpdateE( aProton ); |
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356 | targetHasChanged = true; |
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357 | } |
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358 | else // charge mismatch |
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359 | { |
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360 | currentParticle.SetDefinitionAndUpdateE( aSigmaPlus ); |
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361 | incidentHasChanged = true; |
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362 | targetParticle.SetDefinitionAndUpdateE( aProton ); |
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363 | targetHasChanged = true; |
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364 | // |
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365 | // correct the strangeness by replacing a pi- by a kaon- |
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366 | // |
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367 | vec.Initialize( 1 ); |
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368 | G4ReactionProduct *p = new G4ReactionProduct; |
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369 | p->SetDefinition( aKaonMinus ); |
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370 | (G4UniformRand() < 0.5) ? p->SetSide( -1 ) : p->SetSide( 1 ); |
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371 | vec.SetElement( vecLen++, p ); |
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372 | --nm; |
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373 | } |
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374 | } |
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375 | else if( np+1 == nm ) |
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376 | { |
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377 | if( G4UniformRand() < 0.5 ) |
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378 | { |
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379 | currentParticle.SetDefinitionAndUpdateE( aXiZero ); |
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380 | incidentHasChanged = true; |
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381 | } |
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382 | else |
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383 | { |
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384 | targetParticle.SetDefinitionAndUpdateE( aProton ); |
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385 | targetHasChanged = true; |
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386 | } |
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387 | } |
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388 | } |
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389 | SetUpPions( np, nm, nz, vec, vecLen ); |
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390 | return; |
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391 | } |
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392 | |
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393 | /* end of file */ |
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394 | |
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