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2 | // ******************************************************************** |
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3 | // * License and Disclaimer * |
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13 | // * work make any representation or warranty, express or implied, * |
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15 | // * use. Please see the license in the file LICENSE and URL above * |
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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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24 | // ******************************************************************** |
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25 | // |
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26 | // |
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27 | // $Id: G4QProbability.cc,v 1.3 2009/09/04 16:13:19 mkossov Exp $ |
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28 | // GEANT4 tag $Name: hadr-chips-V09-03-08 $ |
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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 | // ---------------- G4QProbability ---------------- |
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34 | // by Mikhail Kossov Oct, 2006 |
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35 | // class for Pomeron & Reggeon amplitudes used by CHIPS |
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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. Others |
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42 | // are Reggeons and, possibly Instantons (for spin-flip reactions). |
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43 | // Strings are cuts of Pomerons and Reggeons (optic theorem connects |
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44 | // the amplitude of scattering at zero angle with the total inelastic |
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45 | // cross-section). They describe inelastic processes at high energies. |
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46 | // ------------------------------------------------------------------ |
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47 | |
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48 | #include "G4QProbability.hh" |
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49 | |
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50 | G4QProbability::G4QProbability(G4int PDG) |
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51 | { |
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52 | S0 = 1.*GeV*GeV; // Must be a constant (just GeV^2 unit !) |
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53 | pom_Alpha = 1.0808; // Must be the same for all hadrons |
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54 | pom_Alphaprime = 0.25/GeV/GeV; |
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55 | qex_Gamma = 9./GeV/GeV; |
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56 | qex_R2 = 27./GeV/GeV; |
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57 | qex_Alphaprime = 1.5/GeV/GeV; |
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58 | |
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59 | G4int aP = std::abs(PDG); |
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60 | if (PDG==2212 || PDG==2112) InitForNucleon(); |
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61 | else if(PDG==111 || aP==211) InitForPion(); |
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62 | else if(PDG==130 || PDG==310 || aP==311 || aP==321) InitForKaon(); |
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63 | else if(PDG==22) InitForGamma(); |
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64 | else if(PDG > 3000) InitForHyperon(); |
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65 | else if(PDG <-2000) InitForAntiBaryon(); |
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66 | else |
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67 | { |
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68 | G4cout<<"-Warning-G4QProbability is initialized for PDGCode="<<PDG<<" as Pion"<<G4endl; |
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69 | InitForPion(); |
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70 | } |
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71 | pom_sqC=std::sqrt(pom_C); |
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72 | } |
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73 | |
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74 | G4double G4QProbability::GetCutPomProbability(const G4double s, const G4double imp2, |
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75 | const G4int nPom) |
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76 | { |
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77 | static const G4int nft=11; |
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78 | static const G4int nf1=nft-1; |
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79 | static const G4double ft[nft]={1.,1.,2.,6.,24.,120.,720.,5040.,40320.,362880.,3628800.}; |
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80 | if(nPom<0) return 0.; |
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81 | G4double f=ft[nf1]; |
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82 | if(nPom<nft) f=ft[nPom]; |
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83 | else for(G4int i=nft; i<= nPom; i++) f*=i; // Calculate factorial for high nPom |
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84 | G4double e=PomEikonal(s,imp2); e+=e; // Doubled Eikonal |
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85 | return std::exp(-e)*std::pow(e,nPom)/pom_C/f; |
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86 | } |
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87 | |
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88 | G4double G4QProbability::GetCutQexProbability(const G4double s, const G4double imp2, |
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89 | const G4int nQex) |
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90 | { |
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91 | static const G4int nft=11; |
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92 | static const G4int nf1=nft-1; |
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93 | static const G4double ft[nft]={1.,1.,2.,6.,24.,120.,720.,5040.,40320.,362880.,3628800.}; |
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94 | if(nQex<0) return 0.; |
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95 | G4double f=ft[nf1]; |
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96 | if(nQex<nft) f=ft[nQex]; |
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97 | else for(G4int i=nft; i<= nQex; i++) f*=i; // Calculate factorial for high nPom |
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98 | G4double e=QexEikonal(s,imp2); e+=e; // Doubled Eikonal |
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99 | return std::exp(-e)*std::pow(e,nQex)/f; |
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100 | } |
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101 | |
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102 | void G4QProbability::InitForNucleon() |
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103 | { |
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104 | pom_Gamma = 2.16/GeV/GeV; // ? M.K.@@ Must be taken from total cross-sections |
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105 | pom_C = 1.4; |
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106 | pom_R2 = 3.30/GeV/GeV; |
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107 | } |
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108 | |
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109 | void G4QProbability::InitForHyperon() |
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110 | { |
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111 | pom_Gamma = 2.16/GeV/GeV; // ? M.K.@@ Must be taken from total cross-sections |
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112 | pom_C = 1.4; |
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113 | pom_R2 = 3.30/GeV/GeV; // ? M.K.@@ Just a guess |
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114 | } |
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115 | void G4QProbability::InitForAntiBaryon() |
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116 | { |
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117 | pom_Gamma = 2.16/GeV/GeV; // ? M.K.@@ Must be taken from total cross-sections |
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118 | pom_C = 1.4; |
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119 | pom_R2 = 3.30/GeV/GeV; |
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120 | } |
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121 | |
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122 | void G4QProbability::InitForPion() |
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123 | { |
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124 | pom_Gamma = 2.16/GeV/GeV; // ? M.K.@@ Must be taken from total cross-sections |
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125 | pom_C = 1.6; // Only: for mesons it is bigger than for baryons |
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126 | pom_R2 = 2.36/GeV/GeV; |
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127 | } |
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128 | |
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129 | void G4QProbability::InitForKaon() |
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130 | { |
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131 | pom_Gamma = 1.92/GeV/GeV; // ? M.K.@@ Must be taken from total cross-sections |
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132 | pom_C = 1.8; // 1.7 (?) |
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133 | pom_R2 = 1.96/GeV/GeV; // ? M.K.@@ Just a guess |
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134 | } |
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135 | |
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136 | void G4QProbability::InitForGamma() |
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137 | { |
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138 | pom_Gamma = 2.16/GeV/GeV; // ? M.K.@@ Must be taken from total cross-sections |
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139 | pom_C = 1.7; |
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140 | pom_R2 = 2.16/GeV/GeV; // ? M.K.@@ Just a guess |
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141 | } |
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142 | |
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143 | G4double G4QProbability::Expand(G4double z) |
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144 | { |
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145 | G4double sum=1.; |
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146 | G4double current=1.; |
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147 | for(G4int j=2; j<21; j++) |
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148 | { |
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149 | current *= -z*(j-1)/j/j; |
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150 | sum+=current; |
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151 | } |
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152 | return sum; |
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153 | } |
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154 | |
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155 | G4double G4QProbability::GetQexTotProbability(const G4double s, const G4double imp2) |
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156 | { |
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157 | G4double ExpPom=std::exp(-PomEikonal(s,imp2)); |
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158 | G4double ExpQex=std::exp(-QexEikonal(s,imp2)); |
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159 | G4double Amp=(ExpQex*(1.-ExpPom) + sqr(pom_sqC-1.)*ExpPom*(1.-ExpQex))/pom_C; |
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160 | return Amp+Amp; |
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161 | } |
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162 | |
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163 | G4double G4QProbability::GetQexElProbability(const G4double s, const G4double imp2) |
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164 | { |
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165 | G4double ExpPom=std::exp(-PomEikonal(s,imp2)); |
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166 | G4double ExpQex=std::exp(-QexEikonal(s,imp2)); |
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167 | G4double Amp=(ExpQex*(1.-ExpPom) + sqr(pom_sqC-1.)*ExpPom*(1.-ExpQex))/pom_C; |
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168 | return Amp*Amp; |
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169 | } |
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170 | |
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171 | G4double G4QProbability::GetQexDubDiffProbability(const G4double s, const G4double imp2) |
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172 | { |
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173 | G4double ExpPom=std::exp(-PomEikonal(s,imp2)); |
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174 | G4double ExpQex=std::exp(-QexEikonal(s,imp2)); |
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175 | G4double Amp=sqr(pom_sqC-1.)*(ExpQex*(1.-ExpPom) + ExpPom*(1.-ExpQex))/pom_C; |
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176 | return Amp*Amp; |
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177 | } |
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178 | |
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179 | G4double G4QProbability::GetQexSinDiffProbability(const G4double s, const G4double imp2) |
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180 | { |
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181 | G4double ExpPom=std::exp(-PomEikonal(s,imp2)); |
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182 | G4double ExpQex=std::exp(-QexEikonal(s,imp2)); |
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183 | G4double Amp=(pom_sqC-1.)*(ExpQex*(1.-ExpPom) - (pom_sqC-1.)*ExpPom*(1.-ExpQex))/pom_C; |
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184 | return Amp*Amp; |
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185 | } |
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186 | |
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187 | G4double G4QProbability::GetQexDiffProbability(const G4double s, const G4double imp2) |
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188 | { |
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189 | return GetQexDubDiffProbability(s,imp2)+2*GetQexSinDiffProbability(s,imp2); |
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190 | } |
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191 | |
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192 | G4double G4QProbability::GetQexInelProbability(const G4double s, const G4double imp2) |
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193 | { |
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194 | G4double ExpPom=std::exp(-PomEikonal(s,imp2)); |
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195 | G4double ExpQex=std::exp(-QexEikonal(s,imp2)); |
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196 | G4double Amp=sqr(pom_sqC-1.)*(ExpQex*(1.-ExpPom) + ExpPom*(1.-ExpQex))/pom_C; |
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197 | return Amp+Amp-Amp*Amp; |
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198 | } |
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