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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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: G4DiffractiveSplitableHadron.cc,v 1.7 2008/03/31 15:34:01 vuzhinsk Exp $ |
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28 | // GEANT4 tag $Name: geant4-09-02 $ |
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29 | // |
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30 | |
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31 | // ------------------------------------------------------------ |
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32 | // GEANT 4 class implementation file |
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33 | // |
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34 | // ---------------- G4DiffractiveSplitableHadron---------------- |
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35 | // by Gunter Folger, August 1998. |
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36 | // class splitting an interacting particle. Used by FTF String Model. |
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37 | // ------------------------------------------------------------ |
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38 | |
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39 | #include "G4DiffractiveSplitableHadron.hh" |
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40 | |
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41 | #include "G4ParticleDefinition.hh" |
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42 | #include "Randomize.hh" |
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43 | |
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44 | G4DiffractiveSplitableHadron::G4DiffractiveSplitableHadron() |
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45 | |
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46 | { |
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47 | } |
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48 | |
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49 | G4DiffractiveSplitableHadron::G4DiffractiveSplitableHadron(const G4ReactionProduct & aPrimary) |
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50 | : G4VSplitableHadron(aPrimary) |
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51 | { |
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52 | PartonIndex=-2; |
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53 | Parton[0]=NULL; |
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54 | } |
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55 | |
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56 | G4DiffractiveSplitableHadron::G4DiffractiveSplitableHadron(const G4Nucleon & aNucleon) |
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57 | : G4VSplitableHadron(aNucleon) |
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58 | { |
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59 | PartonIndex=-2; |
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60 | Parton[0]=NULL; |
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61 | } |
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62 | |
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63 | G4DiffractiveSplitableHadron::G4DiffractiveSplitableHadron(const G4VKineticNucleon * aNucleon) |
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64 | : G4VSplitableHadron(aNucleon) |
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65 | { |
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66 | PartonIndex=-2; |
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67 | Parton[0]=NULL; |
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68 | } |
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69 | |
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70 | G4DiffractiveSplitableHadron::~G4DiffractiveSplitableHadron() |
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71 | {} |
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72 | |
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73 | const G4DiffractiveSplitableHadron & G4DiffractiveSplitableHadron::operator=(const G4DiffractiveSplitableHadron &) |
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74 | { |
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75 | throw G4HadronicException(__FILE__, __LINE__, "G4DiffractiveSplitableHadron::operator= meant to not be accessable"); |
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76 | return *this; |
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77 | } |
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78 | |
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79 | void G4DiffractiveSplitableHadron::SplitUp() |
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80 | { |
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81 | if (IsSplit()) return; |
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82 | Splitting(); |
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83 | // Split once only... |
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84 | if (Parton[0] != NULL) return; |
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85 | |
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86 | // flavours of quark ends |
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87 | |
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88 | G4int PDGcode=GetDefinition()->GetPDGEncoding(); |
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89 | G4int stringStart, stringEnd; |
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90 | ChooseStringEnds(PDGcode, &stringStart,&stringEnd); |
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91 | |
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92 | Parton[0] = new G4Parton(stringStart); |
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93 | Parton[1] = new G4Parton(stringEnd); |
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94 | PartonIndex=-1; |
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95 | |
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96 | } |
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97 | |
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98 | G4Parton * G4DiffractiveSplitableHadron::GetNextParton() |
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99 | { |
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100 | ++PartonIndex; |
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101 | if ( PartonIndex > 1 || PartonIndex < 0 ) return NULL; |
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102 | |
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103 | return Parton[PartonIndex]; |
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104 | } |
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105 | |
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106 | G4Parton * G4DiffractiveSplitableHadron::GetNextAntiParton() |
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107 | { |
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108 | return NULL; // to be looked at @@ |
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109 | } |
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110 | |
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111 | // |
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112 | //----------------------- Implementation-------------------------- |
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113 | // |
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114 | |
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115 | void G4DiffractiveSplitableHadron::ChooseStringEnds(G4int PDGcode,G4int * aEnd, G4int * bEnd) const |
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116 | { |
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117 | const G4double udspin1= 1./6.; |
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118 | const G4double uuspin1= 1./3.; |
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119 | // const G4double udspin0= 1./2.; //@ |
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120 | |
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121 | G4int absPDGcode=std::abs(PDGcode); |
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122 | |
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123 | if ( absPDGcode < 1000 ) //-------------------- Meson ------------- |
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124 | { |
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125 | G4int heavy= absPDGcode/ 100; |
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126 | G4int light= (absPDGcode %100)/10; |
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127 | |
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128 | // G4int anti= std::pow(-1 , std::max( heavy, light)); |
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129 | G4int anti= 1 -2 * ( std::max( heavy, light ) % 2 ); |
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130 | if (PDGcode < 0 ) anti *=-1; |
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131 | |
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132 | heavy *= anti; |
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133 | light *= -1 * anti; |
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134 | |
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135 | if ( G4UniformRand() < 0.5 ) |
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136 | { |
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137 | *aEnd=heavy; |
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138 | *bEnd=light; |
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139 | } |
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140 | else |
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141 | { |
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142 | *aEnd=light; |
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143 | *bEnd=heavy; |
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144 | } |
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145 | } |
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146 | else //-------------------- Barion -------------- |
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147 | { |
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148 | G4int j1000 = PDGcode/ 1000; |
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149 | G4int j100 = (PDGcode % 1000) / 100; |
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150 | G4int j10 = (PDGcode % 100) / 10; |
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151 | |
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152 | G4double random= G4UniformRand(); |
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153 | |
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154 | |
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155 | if ( std::abs(j100) >= std::abs(j10) ) |
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156 | { |
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157 | if ( random < udspin1 ) |
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158 | { |
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159 | *aEnd=j1000; |
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160 | *bEnd= Diquark( j100, j10, 1); |
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161 | } else if ( random < (udspin1 + uuspin1) ) |
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162 | { |
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163 | *aEnd= j10; |
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164 | *bEnd= Diquark( j1000, j100, 1); |
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165 | } else |
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166 | { |
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167 | *aEnd=j100; |
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168 | // Careful, there is no diquark q1=q2, (q1 q2)0, |
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169 | // possible for Omega- |
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170 | *bEnd= Diquark( j1000, j10, j1000 != j100 ? 0 : 1); |
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171 | } |
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172 | } else |
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173 | { |
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174 | // Lambda-like hadrons have two lightest quarks in spin 0 |
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175 | if ( random < udspin1 ) |
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176 | { |
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177 | *aEnd=j1000; |
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178 | // as above, but with charmed barions |
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179 | *bEnd= Diquark( j100, j10, j100 != j10 ? 0 : 10); |
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180 | } else if ( random < (udspin1 + uuspin1) ) |
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181 | { |
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182 | *aEnd= j10; |
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183 | *bEnd= Diquark( j1000, j100, 1); |
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184 | } else |
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185 | { |
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186 | *aEnd=j100; |
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187 | *bEnd= Diquark( j1000, j10, 1); |
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188 | } |
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189 | |
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190 | } |
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191 | |
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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 | |
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198 | G4int G4DiffractiveSplitableHadron::Diquark(G4int aquark,G4int bquark,G4int Spin) const |
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199 | { |
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200 | G4int diquarkPDG; |
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201 | |
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202 | diquarkPDG = std::max( std::abs(aquark), std::abs(bquark) )*1000 + |
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203 | std::min( std::abs(aquark), std::abs(bquark) )*100 + |
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204 | 2*Spin + 1; |
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205 | return ( aquark > 0 && bquark > 0 ) ? diquarkPDG : -1*diquarkPDG; |
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206 | } |
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