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2 | // ******************************************************************** |
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3 | // * License and Disclaimer * |
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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 | // ------------------------------------------------------------------- |
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28 | // GEANT4 Class file |
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29 | // |
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30 | // For information related to this code contact: |
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31 | // |
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32 | // File name: G4VXResonance |
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33 | // |
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34 | // Author: |
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35 | // |
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36 | // Creation date: 15 April 1999 |
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37 | // |
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38 | // Modifications: |
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39 | // |
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40 | // ------------------------------------------------------------------- |
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41 | |
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42 | #include "globals.hh" |
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43 | #include "G4ios.hh" |
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44 | #include "G4KineticTrack.hh" |
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45 | #include "G4VXResonance.hh" |
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46 | #include "Randomize.hh" |
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47 | #include "G4Proton.hh" |
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48 | #include "G4HadTmpUtil.hh" |
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49 | |
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50 | G4VXResonance::G4VXResonance() |
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51 | { } |
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52 | |
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53 | |
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54 | G4VXResonance::~G4VXResonance() |
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55 | { } |
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56 | |
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57 | |
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58 | G4bool G4VXResonance::operator==(const G4VXResonance &right) const |
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59 | { |
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60 | return (this == (G4VXResonance *) &right); |
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61 | } |
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62 | |
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63 | |
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64 | G4bool G4VXResonance::operator!=(const G4VXResonance &right) const |
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65 | { |
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66 | return (this != (G4VXResonance *) &right); |
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67 | } |
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68 | |
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69 | |
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70 | G4double G4VXResonance::IsospinCorrection(const G4KineticTrack& trk1, |
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71 | const G4KineticTrack& trk2, |
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72 | G4int isoOut1, G4int isoOut2, |
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73 | G4double /*iSpinOut1*/, G4double /*iSpinOut2*/) const |
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74 | { |
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75 | G4double result = 0.; |
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76 | |
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77 | G4ParticleDefinition* in1 = trk1.GetDefinition(); |
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78 | G4ParticleDefinition* in2 = trk2.GetDefinition(); |
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79 | |
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80 | G4int isoIn1 = in1->GetPDGiIsospin(); |
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81 | G4int iso3In1 = in1->GetPDGiIsospin3(); |
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82 | G4int isoIn2 = in2->GetPDGiIsospin(); |
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83 | G4int iso3In2 = in2->GetPDGiIsospin3(); |
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84 | |
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85 | G4int isoProton = G4Proton::ProtonDefinition()->GetPDGiIsospin(); |
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86 | G4int iso3Proton = G4Proton::ProtonDefinition()->GetPDGiIsospin3(); |
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87 | |
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88 | G4double pWeight = clebsch.Weight(isoProton,iso3Proton, isoProton,iso3Proton, isoOut1,isoOut2); |
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89 | if (pWeight == 0.) throw G4HadronicException(__FILE__, __LINE__, "G4VXResonance::IsospinCorrection, no resonances - pWeight is zero"); |
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90 | |
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91 | if (in1->IsShortLived() || in2->IsShortLived()) |
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92 | { |
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93 | // Resonances in the initial state |
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94 | G4int iSpinProton = G4Proton::ProtonDefinition()->GetPDGiSpin(); |
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95 | G4double degeneracyFactor = DegeneracyFactor(trk1,trk2,iSpinProton,iSpinProton); |
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96 | |
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97 | G4double factor = degeneracyFactor * pWeight; |
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98 | if (factor > DBL_MIN) |
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99 | { |
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100 | // Randomly select the Isospin3 of the initial state resonances |
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101 | std::vector<G4double> iso = clebsch.GenerateIso3(isoIn1,iso3In1, |
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102 | isoIn2,iso3In2, |
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103 | isoProton,isoProton); |
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104 | G4int isoA = G4lrint(iso[0]); |
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105 | G4int isoB = G4lrint(iso[1]); |
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106 | G4double rWeight = clebsch.Weight(isoProton,isoA, |
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107 | isoProton,isoB, |
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108 | isoOut1,isoOut2); |
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109 | result = rWeight / pWeight; |
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110 | } |
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111 | } |
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112 | else |
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113 | { |
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114 | G4double weight = clebsch.Weight(isoIn1,iso3In1, isoIn2,iso3In2, isoOut1,isoOut2); |
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115 | result = weight / pWeight; |
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116 | } |
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117 | |
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118 | return result; |
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119 | } |
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120 | |
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121 | |
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122 | #include "G4DetailedBalancePhaseSpaceIntegral.hh" |
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123 | |
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124 | G4double G4VXResonance::DetailedBalance(const G4KineticTrack& trk1, |
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125 | const G4KineticTrack& trk2, |
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126 | G4int isoOut1, G4int isoOut2, |
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127 | G4double iSpinOut1, G4double iSpinOut2, |
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128 | G4double mOut1, G4double mOut2) const |
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129 | { |
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130 | // To handle the cases when resonances are involved the modified |
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131 | // detailed balance of P. Danielewicz and G.F. Bertsch, Nucl. Phys. A533(1991) 712 |
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132 | // is used; in other words, the width of the resonances are folded to get the |
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133 | // mean square of the final state momentum. |
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134 | |
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135 | G4ParticleDefinition* in1 = trk1.GetDefinition(); |
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136 | G4ParticleDefinition* in2 = trk2.GetDefinition(); |
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137 | if(in1->IsShortLived() && in2->IsShortLived()) |
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138 | { |
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139 | throw G4HadronicException(__FILE__, __LINE__, "Detailed balance for resonance scattering still on the schedule."); |
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140 | } |
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141 | |
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142 | G4double result = 0.; |
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143 | |
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144 | G4int isoIn1 = in1->GetPDGiIsospin(); |
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145 | G4int iso3In1 = in1->GetPDGiIsospin3(); |
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146 | G4int isoIn2 = in2->GetPDGiIsospin(); |
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147 | G4int iso3In2 = in2->GetPDGiIsospin3(); |
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148 | G4double weight = clebsch.Weight(isoIn1, iso3In1, isoIn2, iso3In2, isoOut1, isoOut2); |
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149 | |
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150 | if (weight > 00001) |
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151 | { |
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152 | // adding spin counting here ...... does not look quite consistent, but is correct anyway. |
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153 | // revisit in the next design iteration @@ |
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154 | G4double degeneracy = DegeneracyFactor(trk1,trk2,iSpinOut1,iSpinOut2); |
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155 | G4double factor = degeneracy * weight; |
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156 | |
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157 | // now the phase-space |
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158 | G4double s = (trk1.Get4Momentum() + trk2.Get4Momentum()).mag2(); |
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159 | G4double m1 = in1->GetPDGMass(); |
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160 | G4double m2 = in2->GetPDGMass(); |
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161 | |
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162 | // on-shell |
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163 | G4double pinitial2 = (s - (m1+m2) * (m1+m2)) * (s - (m1-m2) * (m1-m2)) / (4.0*s); |
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164 | G4double pfinal2 = (s - (mOut1+mOut2) * (mOut1+mOut2)) * (s - ( mOut1-mOut2) * (mOut1-mOut2)) / (4.0*s); |
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165 | G4double relativeMomsquared = pfinal2/pinitial2; |
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166 | |
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167 | // resonance-nucleon scattering - inverse channel |
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168 | if(in1->IsShortLived()) |
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169 | { |
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170 | G4DetailedBalancePhaseSpaceIntegral theI(in1); |
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171 | relativeMomsquared = 1./theI.GetPhaseSpaceIntegral(std::sqrt(s)); |
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172 | } |
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173 | else if(in2->IsShortLived()) |
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174 | { |
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175 | G4DetailedBalancePhaseSpaceIntegral theI(in2); |
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176 | relativeMomsquared = 1./theI.GetPhaseSpaceIntegral(std::sqrt(s)); |
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177 | } |
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178 | |
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179 | result = factor * relativeMomsquared; |
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180 | } |
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181 | |
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182 | return result; |
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183 | } |
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184 | |
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185 | |
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186 | G4double G4VXResonance::DegeneracyFactor(const G4KineticTrack& trk1, |
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187 | const G4KineticTrack& trk2, |
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188 | G4double iSpinOut1, G4double iSpinOut2) const |
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189 | { |
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190 | G4double value = 0.; |
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191 | |
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192 | G4ParticleDefinition* in1 = trk1.GetDefinition(); |
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193 | G4ParticleDefinition* in2 = trk2.GetDefinition(); |
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194 | |
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195 | G4double sIn1 = in1->GetPDGiSpin() + 1.; |
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196 | G4double sIn2 = in2->GetPDGiSpin() + 1.; |
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197 | |
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198 | G4double denom = sIn1 * sIn2; |
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199 | if (denom > 0.) |
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200 | { |
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201 | value = (iSpinOut1+1) * (iSpinOut2+1) / denom; |
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202 | } |
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203 | return value; |
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204 | } |
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205 | |
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206 | |
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