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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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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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: G4QPomeron.cc,v 1.3 2009/02/23 09:49:24 mkossov Exp $ |
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28 | // GEANT4 tag $Name: geant4-09-03-beta-cand-01 $ |
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29 | // |
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30 | // ------------------------------------------------------------ |
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31 | // GEANT 4 class implementation file |
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32 | // |
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33 | // ---------------- G4QPomeron ---------------- |
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34 | // by Mikhail Kossov Oct, 2006 |
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35 | // class for a Pomeron used by Parton String Models |
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36 | // For comparison mirror member functions are taken from G4 class: |
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37 | // G4PomeronCrossSection |
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38 | // ------------------------------------------------------------------ |
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39 | // Short description: Pomeron is one of the possible vacuum pole (the |
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40 | // second is Oderon, but they are identical in the present model), by |
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41 | // which particle exchang in the ellastic scattering process. Strings, |
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42 | // which appear as a cut of the Pomeron (optic theorem connects the |
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43 | // amplitude of scattering at zero angle with the total inelastic |
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44 | // cross-section), describe most of the processes at high energies. |
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45 | // ------------------------------------------------------------------ |
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46 | |
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47 | #include "G4QPomeron.hh" |
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48 | |
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49 | G4QPomeron::G4QPomeron(G4int PDG) |
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50 | { |
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51 | pomeron_Alpha= 1.0808; |
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52 | pomeron_Alphaprime = 0.25/GeV/GeV; |
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53 | pomeron_Gamma_Hard = 0.0002/GeV/GeV; |
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54 | pomeron_Alpha_Hard = 1.47; |
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55 | G4int aP = std::abs(PDG); |
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56 | if (aP==2212||aP==2112) InitForNucleon(); |
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57 | else if(PDG==111||aP==211) InitForPion(); |
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58 | else if(PDG==130||PDG==310||aP==311||aP==321) InitForKaon(); |
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59 | else if(PDG==22) InitForGamma(); |
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60 | else if(aP==3122||aP==3222||aP==3212||aP==3112||aP==3322||aP==3312||aP==3334) |
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61 | InitForNucleon(); |
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62 | else |
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63 | { |
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64 | G4cout<<"-Warning-G4QPomeron is initialised for PDGCode="<<PDG<<" as a pion"<<G4endl; |
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65 | InitForPion(); |
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66 | } |
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67 | } |
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68 | |
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69 | G4double G4QPomeron::GetCutPomeronProbability(const G4double s,const G4double imp2, |
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70 | const G4int nPom) |
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71 | { |
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72 | G4double f=1; if(nPom>1) for(G4int i=2; i<= nPom; i++) f*=i; // Calculate factorial |
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73 | G4double e=Eikonal(s,imp2); e+=e; // Doubled Eikonal |
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74 | return std::exp(-e)*std::pow(e,nPom)/pomeron_C/f; |
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75 | } |
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76 | |
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77 | void G4QPomeron::InitForNucleon() |
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78 | { |
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79 | // pomeron_S= 3.0*GeV*GeV; |
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80 | pomeron_S= 2.7*GeV*GeV; |
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81 | // pomeron_Gamma= 2.16/GeV/GeV; // ? M.K. |
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82 | // pomeron_Gamma= 3.96/GeV/GeV; // ? M.K. |
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83 | pomeron_Gamma = (2.6+3.96)/GeV/GeV; // ? M.K. |
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84 | pomeron_C = 1.4; |
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85 | pomeron_Rsquare = 3.56/GeV/GeV; |
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86 | /////pomeron_Alpha= 0.9808; // This is very strange M.K. (was in GHAD QGSM) |
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87 | // If pomeron_Gamma_Hard!=0 to fit total pp XS use pomeron_Gamma_Soft=2.35/GeV/GeV ? M.K. |
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88 | } |
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89 | |
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90 | void G4QPomeron::InitForPion() |
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91 | { |
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92 | pomeron_S = 1.5*GeV*GeV; |
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93 | //pomeron_Gamma = 1.46/GeV/GeV; // ? M.K. |
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94 | pomeron_Gamma = 2.17/GeV/GeV; // ? M.K. |
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95 | pomeron_C = 1.6; |
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96 | pomeron_Rsquare = 2.36/GeV/GeV; |
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97 | } |
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98 | |
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99 | void G4QPomeron::InitForKaon() |
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100 | { |
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101 | pomeron_S = 2.3*GeV*GeV; |
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102 | //pomeron_Gamma = 1.31/GeV/GeV; // ? M.K. |
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103 | pomeron_Gamma = 1.92/GeV/GeV; // ? M.K. |
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104 | pomeron_C = 1.8; |
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105 | pomeron_Rsquare = 1.96/GeV/GeV; |
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106 | } |
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107 | |
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108 | void G4QPomeron::InitForGamma() |
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109 | { |
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110 | pomeron_S = 1.7*GeV*GeV; |
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111 | //pomeron_Gamma = 1.42/GeV/GeV; // ? M.K. |
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112 | pomeron_Gamma = 2.07/GeV/GeV; // ? M.K. |
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113 | pomeron_C = 1.7; |
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114 | pomeron_Rsquare = 2.16/GeV/GeV; |
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115 | } |
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116 | |
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117 | G4double G4QPomeron::Expand(G4double z) |
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118 | { |
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119 | |
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120 | G4double sum=1.; |
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121 | G4double current=1.; |
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122 | for(G4int j=2; j<21; j++) |
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123 | { |
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124 | current *= -z*(j-1)/j/j; |
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125 | sum+=current; |
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126 | } |
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127 | return sum; |
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128 | } |
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129 | |
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130 | |
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131 | |
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132 | |
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133 | |
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134 | |
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135 | |
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136 | |
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137 | |
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138 | |
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139 | |
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