[819] | 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 | // |
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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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