1 | // SigmaQCD.h is a part of the PYTHIA event generator. |
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2 | // Copyright (C) 2012 Torbjorn Sjostrand. |
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3 | // PYTHIA is licenced under the GNU GPL version 2, see COPYING for details. |
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4 | // Please respect the MCnet Guidelines, see GUIDELINES for details. |
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5 | |
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6 | // Header file for QCD process differential cross sections. |
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7 | // Contains classes derived from SigmaProcess via Sigma(0/2)Process. |
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8 | |
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9 | #ifndef Pythia8_SigmaQCD_H |
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10 | #define Pythia8_SigmaQCD_H |
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11 | |
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12 | #include "SigmaProcess.h" |
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13 | |
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14 | namespace Pythia8 { |
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15 | |
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16 | //========================================================================== |
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17 | |
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18 | // A derived class for minimum-bias (inelastic, nondiffractive) events. |
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19 | |
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20 | class Sigma0minBias : public Sigma0Process { |
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21 | |
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22 | public: |
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23 | |
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24 | // Constructor. |
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25 | Sigma0minBias() {} |
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26 | |
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27 | // Evaluate sigma. |
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28 | virtual double sigmaHat() {return sigmaTotPtr->sigmaND();} |
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29 | |
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30 | // Select flavour, colour and anticolour. |
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31 | virtual void setIdColAcol() {} |
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32 | |
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33 | // Info on the subprocess. |
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34 | virtual string name() const {return "minimum bias";} |
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35 | virtual int code() const {return 101;} |
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36 | virtual bool isMinBias() const {return true;} |
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37 | |
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38 | private: |
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39 | |
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40 | }; |
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41 | |
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42 | //========================================================================== |
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43 | |
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44 | // A derived class for elastic scattering A B -> A B. |
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45 | |
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46 | class Sigma0AB2AB : public Sigma0Process { |
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47 | |
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48 | public: |
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49 | |
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50 | // Constructor. |
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51 | Sigma0AB2AB() {} |
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52 | |
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53 | // Evaluate sigma. |
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54 | virtual double sigmaHat() {return sigmaTotPtr->sigmaEl();} |
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55 | |
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56 | // Select flavour, colour and anticolour. |
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57 | virtual void setIdColAcol(); |
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58 | |
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59 | // Info on the subprocess. |
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60 | virtual string name() const {return "A B -> A B elastic";} |
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61 | virtual int code() const {return 102;} |
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62 | virtual bool isResolved() const {return false;} |
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63 | |
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64 | private: |
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65 | |
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66 | }; |
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67 | |
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68 | //========================================================================== |
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69 | |
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70 | // A derived class for single diffractive scattering A B -> X B. |
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71 | |
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72 | class Sigma0AB2XB : public Sigma0Process { |
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73 | |
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74 | public: |
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75 | |
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76 | // Constructor. |
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77 | Sigma0AB2XB() {} |
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78 | |
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79 | // Evaluate sigma. |
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80 | virtual double sigmaHat() {return sigmaTotPtr->sigmaXB();} |
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81 | |
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82 | // Select flavour, colour and anticolour. |
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83 | virtual void setIdColAcol(); |
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84 | |
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85 | // Info on the subprocess. |
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86 | virtual string name() const {return "A B -> X B single diffractive";} |
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87 | virtual int code() const {return 103;} |
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88 | virtual bool isResolved() const {return false;} |
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89 | virtual bool isDiffA() const {return true;}; |
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90 | |
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91 | private: |
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92 | |
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93 | }; |
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94 | |
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95 | //========================================================================== |
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96 | |
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97 | // A derived class for single diffractive scattering A B -> A X. |
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98 | |
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99 | class Sigma0AB2AX : public Sigma0Process { |
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100 | |
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101 | public: |
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102 | |
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103 | // Constructor. |
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104 | Sigma0AB2AX() {} |
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105 | |
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106 | // Evaluate sigma. |
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107 | virtual double sigmaHat() {return sigmaTotPtr->sigmaAX();} |
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108 | |
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109 | // Select flavour, colour and anticolour. |
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110 | virtual void setIdColAcol(); |
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111 | |
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112 | // Info on the subprocess. |
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113 | virtual string name() const {return "A B -> A X single diffractive";} |
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114 | virtual int code() const {return 104;} |
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115 | virtual bool isResolved() const {return false;} |
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116 | virtual bool isDiffB() const {return true;}; |
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117 | |
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118 | private: |
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119 | |
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120 | }; |
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121 | |
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122 | //========================================================================== |
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123 | |
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124 | // A derived class for double diffractive scattering A B -> X X. |
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125 | |
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126 | class Sigma0AB2XX : public Sigma0Process { |
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127 | |
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128 | public: |
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129 | |
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130 | // Constructor. |
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131 | Sigma0AB2XX() {} |
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132 | |
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133 | // Evaluate sigma. |
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134 | virtual double sigmaHat() {return sigmaTotPtr->sigmaXX();} |
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135 | |
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136 | // Select flavour, colour and anticolour. |
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137 | virtual void setIdColAcol(); |
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138 | |
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139 | // Info on the subprocess. |
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140 | virtual string name() const {return "A B -> X X double diffractive";} |
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141 | virtual int code() const {return 105;} |
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142 | virtual bool isResolved() const {return false;} |
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143 | virtual bool isDiffA() const {return true;}; |
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144 | virtual bool isDiffB() const {return true;}; |
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145 | |
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146 | private: |
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147 | |
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148 | }; |
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149 | |
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150 | //========================================================================== |
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151 | |
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152 | // A derived class for central diffractive scattering A B -> A X B. |
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153 | |
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154 | class Sigma0AB2AXB : public Sigma0Process { |
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155 | |
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156 | public: |
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157 | |
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158 | // Constructor. |
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159 | Sigma0AB2AXB() {} |
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160 | |
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161 | // Evaluate sigma. |
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162 | virtual double sigmaHat() {return sigmaTotPtr->sigmaAXB();} |
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163 | |
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164 | // Select flavour, colour and anticolour. |
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165 | virtual void setIdColAcol(); |
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166 | |
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167 | // Info on the subprocess. |
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168 | virtual string name() const {return "A B -> A X B central diffractive";} |
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169 | virtual int code() const {return 106;} |
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170 | virtual int nFinal() const {return 3;} |
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171 | virtual bool isResolved() const {return false;} |
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172 | virtual bool isDiffC() const {return true;}; |
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173 | |
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174 | private: |
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175 | |
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176 | }; |
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177 | |
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178 | //========================================================================== |
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179 | |
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180 | // A derived class for g g -> g g. |
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181 | |
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182 | class Sigma2gg2gg : public Sigma2Process { |
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183 | |
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184 | public: |
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185 | |
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186 | // Constructor. |
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187 | Sigma2gg2gg() {} |
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188 | |
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189 | // Calculate flavour-independent parts of cross section. |
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190 | virtual void sigmaKin(); |
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191 | |
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192 | // Evaluate d(sigmaHat)/d(tHat). |
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193 | virtual double sigmaHat() {return sigma;} |
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194 | |
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195 | // Select flavour, colour and anticolour. |
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196 | virtual void setIdColAcol(); |
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197 | |
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198 | // Info on the subprocess. |
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199 | virtual string name() const {return "g g -> g g";} |
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200 | virtual int code() const {return 111;} |
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201 | virtual string inFlux() const {return "gg";} |
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202 | |
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203 | private: |
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204 | |
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205 | // Values stored for colour flow selection. |
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206 | double sigTS, sigUS, sigTU, sigSum, sigma; |
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207 | |
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208 | }; |
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209 | |
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210 | //========================================================================== |
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211 | |
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212 | // A derived class for g g -> q qbar (q = u, d, s, i.e. almost massless). |
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213 | |
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214 | class Sigma2gg2qqbar : public Sigma2Process { |
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215 | |
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216 | public: |
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217 | |
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218 | // Constructor. |
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219 | Sigma2gg2qqbar() {} |
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220 | |
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221 | // Initialize process. |
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222 | virtual void initProc(); |
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223 | |
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224 | // Calculate flavour-independent parts of cross section. |
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225 | virtual void sigmaKin(); |
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226 | |
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227 | // Evaluate d(sigmaHat)/d(tHat). |
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228 | virtual double sigmaHat() {return sigma;} |
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229 | |
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230 | // Select flavour, colour and anticolour. |
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231 | virtual void setIdColAcol(); |
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232 | |
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233 | // Info on the subprocess. |
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234 | virtual string name() const {return "g g -> q qbar (uds)";} |
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235 | virtual int code() const {return 112;} |
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236 | virtual string inFlux() const {return "gg";} |
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237 | |
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238 | private: |
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239 | |
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240 | // Number of quarks to be considered in massless approximation. |
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241 | int nQuarkNew; |
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242 | |
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243 | // Values stored for colour flow selection. |
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244 | int idNew; |
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245 | double mNew, m2New, sigTS, sigUS, sigSum, sigma; |
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246 | |
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247 | }; |
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248 | |
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249 | //========================================================================== |
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250 | |
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251 | // A derived class for q g -> q g (q = u, d, s, c, b). |
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252 | // Use massless approximation also for Q since no alternative. |
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253 | |
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254 | class Sigma2qg2qg : public Sigma2Process { |
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255 | |
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256 | public: |
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257 | |
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258 | // Constructor. |
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259 | Sigma2qg2qg() {} |
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260 | |
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261 | // Calculate flavour-independent parts of cross section. |
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262 | virtual void sigmaKin(); |
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263 | |
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264 | // Evaluate d(sigmaHat)/d(tHat). |
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265 | virtual double sigmaHat() {return sigma;} |
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266 | |
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267 | // Select flavour, colour and anticolour. |
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268 | virtual void setIdColAcol(); |
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269 | |
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270 | // Info on the subprocess. |
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271 | virtual string name() const {return "q g -> q g";} |
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272 | virtual int code() const {return 113;} |
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273 | virtual string inFlux() const {return "qg";} |
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274 | |
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275 | private: |
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276 | |
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277 | // Values stored for colour flow selection. |
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278 | double mNew, m2New, sigTS, sigTU, sigSum, sigma; |
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279 | |
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280 | }; |
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281 | |
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282 | //========================================================================== |
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283 | |
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284 | // A derived class for q qbar' -> q qbar' or q q' -> q q' |
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285 | // (qbar qbar' -> qbar qbar'), q' may be same as q. |
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286 | |
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287 | class Sigma2qq2qq : public Sigma2Process { |
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288 | |
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289 | public: |
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290 | |
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291 | // Constructor. |
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292 | Sigma2qq2qq() {} |
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293 | |
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294 | // Calculate flavour-independent parts of cross section. |
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295 | virtual void sigmaKin(); |
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296 | |
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297 | // Evaluate d(sigmaHat)/d(tHat). |
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298 | virtual double sigmaHat(); |
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299 | |
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300 | // Select flavour, colour and anticolour. |
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301 | virtual void setIdColAcol(); |
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302 | |
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303 | // Info on the subprocess. |
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304 | virtual string name() const {return "q q(bar)' -> q q(bar)'";} |
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305 | virtual int code() const {return 114;} |
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306 | virtual string inFlux() const {return "qq";} |
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307 | |
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308 | private: |
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309 | |
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310 | // Values stored for colour flow selection. |
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311 | double sigT, sigU, sigTU, sigST, sigSum; |
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312 | |
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313 | }; |
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314 | |
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315 | //========================================================================== |
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316 | |
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317 | // A derived class for q qbar -> g g. |
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318 | |
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319 | class Sigma2qqbar2gg : public Sigma2Process { |
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320 | |
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321 | public: |
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322 | |
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323 | // Constructor. |
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324 | Sigma2qqbar2gg() {} |
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325 | |
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326 | // Calculate flavour-independent parts of cross section. |
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327 | virtual void sigmaKin(); |
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328 | |
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329 | // Evaluate d(sigmaHat)/d(tHat). |
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330 | virtual double sigmaHat() {return sigma;} |
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331 | |
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332 | // Select flavour, colour and anticolour. |
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333 | virtual void setIdColAcol(); |
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334 | |
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335 | // Info on the subprocess. |
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336 | virtual string name() const {return "q qbar -> g g";} |
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337 | virtual int code() const {return 115;} |
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338 | virtual string inFlux() const {return "qqbarSame";} |
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339 | |
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340 | private: |
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341 | |
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342 | // Values stored for colour flow selection. |
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343 | double sigTS, sigUS, sigSum, sigma; |
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344 | |
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345 | }; |
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346 | |
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347 | //========================================================================== |
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348 | |
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349 | // A derived class for q qbar -> q' qbar'. |
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350 | |
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351 | class Sigma2qqbar2qqbarNew : public Sigma2Process { |
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352 | |
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353 | public: |
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354 | |
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355 | // Constructor. |
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356 | Sigma2qqbar2qqbarNew() {} |
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357 | |
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358 | // Initialize process. |
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359 | virtual void initProc(); |
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360 | |
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361 | // Calculate flavour-independent parts of cross section. |
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362 | virtual void sigmaKin(); |
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363 | |
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364 | // Evaluate d(sigmaHat)/d(tHat). |
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365 | virtual double sigmaHat() {return sigma;} |
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366 | |
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367 | // Select flavour, colour and anticolour. |
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368 | virtual void setIdColAcol(); |
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369 | |
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370 | // Info on the subprocess. |
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371 | virtual string name() const {return "q qbar -> q' qbar' (uds)";} |
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372 | virtual int code() const {return 116;} |
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373 | virtual string inFlux() const {return "qqbarSame";} |
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374 | |
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375 | private: |
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376 | |
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377 | // Number of quarks to be considered in massless approximation. |
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378 | int nQuarkNew; |
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379 | |
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380 | // Values stored for colour flow selection. |
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381 | int idNew; |
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382 | double mNew, m2New, sigS, sigma; |
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383 | |
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384 | }; |
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385 | |
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386 | //========================================================================== |
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387 | |
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388 | // A derived class for g g -> Q Qbar (Q = c, b or t). |
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389 | |
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390 | class Sigma2gg2QQbar : public Sigma2Process { |
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391 | |
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392 | public: |
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393 | |
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394 | // Constructor. |
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395 | Sigma2gg2QQbar(int idIn, int codeIn) : idNew(idIn), codeSave(codeIn) {} |
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396 | |
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397 | // Initialize process. |
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398 | virtual void initProc(); |
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399 | |
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400 | // Calculate flavour-independent parts of cross section. |
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401 | virtual void sigmaKin(); |
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402 | |
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403 | // Evaluate d(sigmaHat)/d(tHat). |
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404 | virtual double sigmaHat() {return sigma;} |
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405 | |
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406 | // Select flavour, colour and anticolour. |
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407 | virtual void setIdColAcol(); |
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408 | |
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409 | // Evaluate weight for W decay angles in top decay (else inactive). |
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410 | virtual double weightDecay( Event& process, int iResBeg, int iResEnd); |
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411 | |
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412 | // Info on the subprocess. |
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413 | virtual string name() const {return nameSave;} |
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414 | virtual int code() const {return codeSave;} |
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415 | virtual string inFlux() const {return "gg";} |
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416 | virtual int id3Mass() const {return idNew;} |
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417 | virtual int id4Mass() const {return idNew;} |
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418 | |
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419 | private: |
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420 | |
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421 | // Values stored for process type and colour flow selection. |
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422 | int idNew, codeSave; |
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423 | string nameSave; |
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424 | double sigTS, sigUS, sigSum, sigma, openFracPair; |
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425 | |
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426 | }; |
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427 | |
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428 | //========================================================================== |
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429 | |
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430 | // A derived class for q qbar -> Q Qbar (Q = c, b or t). |
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431 | |
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432 | class Sigma2qqbar2QQbar : public Sigma2Process { |
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433 | |
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434 | public: |
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435 | |
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436 | // Constructor. |
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437 | Sigma2qqbar2QQbar(int idIn, int codeIn) : idNew(idIn), codeSave(codeIn) {} |
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438 | |
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439 | // Initialize process. |
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440 | virtual void initProc(); |
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441 | |
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442 | // Calculate flavour-independent parts of cross section. |
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443 | virtual void sigmaKin(); |
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444 | |
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445 | // Evaluate d(sigmaHat)/d(tHat). |
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446 | virtual double sigmaHat() {return sigma;} |
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447 | |
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448 | // Select flavour, colour and anticolour. |
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449 | virtual void setIdColAcol(); |
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450 | |
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451 | // Evaluate weight for W decay angles in top decay (else inactive). |
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452 | virtual double weightDecay( Event& process, int iResBeg, int iResEnd); |
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453 | |
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454 | // Info on the subprocess. |
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455 | virtual string name() const {return nameSave;} |
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456 | virtual int code() const {return codeSave;} |
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457 | virtual string inFlux() const {return "qqbarSame";} |
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458 | virtual int id3Mass() const {return idNew;} |
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459 | virtual int id4Mass() const {return idNew;} |
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460 | |
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461 | private: |
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462 | |
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463 | // Values stored for process type. |
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464 | int idNew, codeSave; |
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465 | string nameSave; |
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466 | double sigma, openFracPair; |
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467 | |
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468 | }; |
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469 | |
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470 | //========================================================================== |
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471 | |
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472 | // A derived class for g g -> g g g. |
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473 | |
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474 | class Sigma3gg2ggg : public Sigma3Process { |
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475 | |
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476 | public: |
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477 | |
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478 | // Constructor. |
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479 | Sigma3gg2ggg() {} |
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480 | |
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481 | // Calculate flavour-independent parts of cross section. |
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482 | virtual void sigmaKin(); |
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483 | |
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484 | // Evaluate d(sigmaHat)/d(tHat). |
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485 | virtual double sigmaHat() {return sigma;} |
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486 | |
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487 | // Select flavour, colour and anticolour. |
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488 | virtual void setIdColAcol(); |
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489 | |
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490 | // Info on the subprocess. |
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491 | virtual string name() const {return "g g -> g g g";} |
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492 | virtual int code() const {return 131;} |
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493 | virtual int nFinal() const {return 3;} |
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494 | virtual string inFlux() const {return "gg";} |
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495 | virtual bool isQCD3body() const {return true;} |
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496 | |
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497 | private: |
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498 | |
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499 | // Values stored for colour flow selection. |
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500 | double sigma; |
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501 | |
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502 | // Intermediate storage and calculation of four-products. |
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503 | double pp[6][6]; |
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504 | double cycle(int i1, int i2, int i3, int i4, int i5) {return |
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505 | pp[i1][i2] * pp[i2][i3] * pp[i3][i4] * pp[i4][i5] * pp[i5][i1];} |
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506 | |
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507 | }; |
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508 | |
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509 | //========================================================================== |
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510 | |
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511 | // A derived class for q qbar -> g g g. |
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512 | |
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513 | class Sigma3qqbar2ggg : public Sigma3Process { |
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514 | |
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515 | public: |
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516 | |
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517 | // Constructor. |
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518 | Sigma3qqbar2ggg() {} |
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519 | |
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520 | // Calculate flavour-independent parts of cross section. |
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521 | virtual void sigmaKin(); |
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522 | |
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523 | // Evaluate d(sigmaHat)/d(tHat). |
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524 | virtual double sigmaHat() {return sigma;} |
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525 | |
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526 | // Select flavour, colour and anticolour. |
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527 | virtual void setIdColAcol(); |
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528 | |
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529 | // Info on the subprocess. |
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530 | virtual string name() const {return "q qbar -> g g g";} |
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531 | virtual int code() const {return 132;} |
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532 | virtual int nFinal() const {return 3;} |
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533 | virtual string inFlux() const {return "qqbarSame";} |
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534 | virtual bool isQCD3body() const {return true;} |
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535 | |
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536 | protected: |
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537 | |
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538 | // Pick/map a random final state configuration |
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539 | int config; |
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540 | inline void pickFinal() { config = int( 6 * rndmPtr->flat() ); } |
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541 | inline void mapFinal(); |
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542 | |
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543 | // |M|^2 calculation |
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544 | inline double m2Calc(); |
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545 | |
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546 | // Four-vectors for |M|^2 calculation |
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547 | Vec4 pCM[5]; |
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548 | |
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549 | // Intermediate storage and calculation of four-products |
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550 | double a[3], b[3], pp[3][3], ab[3][3]; |
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551 | |
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552 | // Values stored for colour flow selection. |
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553 | double sigma; |
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554 | |
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555 | }; |
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556 | |
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557 | //========================================================================== |
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558 | |
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559 | // A derived class for q g -> q g g |
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560 | // Derived from Sigma3qqbar2ggg |
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561 | |
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562 | class Sigma3qg2qgg : public Sigma3qqbar2ggg { |
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563 | |
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564 | public: |
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565 | |
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566 | // Constructor. |
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567 | Sigma3qg2qgg() {} |
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568 | |
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569 | // Calculate flavour-independent parts of cross section. |
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570 | virtual void sigmaKin(); |
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571 | |
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572 | // Evaluate d(sigmaHat)/d(tHat). |
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573 | virtual double sigmaHat(); |
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574 | |
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575 | // Select flavour, colour and anticolour. |
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576 | virtual void setIdColAcol(); |
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577 | |
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578 | // Info on the subprocess. |
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579 | virtual string name() const {return "q g -> q g g";} |
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580 | virtual int code() const {return 133;} |
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581 | virtual int nFinal() const {return 3;} |
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582 | virtual string inFlux() const {return "qg";} |
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583 | virtual bool isQCD3body() const {return true;} |
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584 | |
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585 | private: |
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586 | |
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587 | // Sigma for (qg) and (gq) incoming |
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588 | double sigma[2]; |
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589 | |
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590 | }; |
---|
591 | |
---|
592 | //========================================================================== |
---|
593 | |
---|
594 | // A derived class for g g -> q qbar g |
---|
595 | // Derived from Sigma3qqbar2ggg |
---|
596 | |
---|
597 | class Sigma3gg2qqbarg : public Sigma3qqbar2ggg { |
---|
598 | |
---|
599 | public: |
---|
600 | |
---|
601 | // Constructor. |
---|
602 | Sigma3gg2qqbarg() {} |
---|
603 | |
---|
604 | // Initialize process. |
---|
605 | virtual void initProc(); |
---|
606 | |
---|
607 | // Calculate flavour-independent parts of cross section. |
---|
608 | virtual void sigmaKin(); |
---|
609 | |
---|
610 | // Select flavour, colour and anticolour. |
---|
611 | virtual void setIdColAcol(); |
---|
612 | |
---|
613 | // Info on the subprocess. |
---|
614 | virtual string name() const {return "g g -> q qbar g";} |
---|
615 | virtual int code() const {return 138;} |
---|
616 | virtual int nFinal() const {return 3;} |
---|
617 | virtual string inFlux() const {return "gg";} |
---|
618 | virtual bool isQCD3body() const {return true;} |
---|
619 | |
---|
620 | private: |
---|
621 | |
---|
622 | // Number of quarks to be considered in massless approximation. |
---|
623 | int nQuarkNew; |
---|
624 | |
---|
625 | }; |
---|
626 | |
---|
627 | //========================================================================== |
---|
628 | |
---|
629 | // A derived class for q q' -> q q' g |
---|
630 | |
---|
631 | class Sigma3qq2qqgDiff : public Sigma3Process { |
---|
632 | |
---|
633 | public: |
---|
634 | |
---|
635 | // Constructor. |
---|
636 | Sigma3qq2qqgDiff() {} |
---|
637 | |
---|
638 | // Calculate flavour-independent parts of cross section. |
---|
639 | virtual void sigmaKin(); |
---|
640 | |
---|
641 | // Evaluate d(sigmaHat)/d(tHat). |
---|
642 | virtual double sigmaHat(); |
---|
643 | |
---|
644 | // Select flavour, colour and anticolour. |
---|
645 | virtual void setIdColAcol(); |
---|
646 | |
---|
647 | // Info on the subprocess. |
---|
648 | virtual string name() const |
---|
649 | {return "q(bar) q(bar)' -> q(bar) q(bar)' g";} |
---|
650 | virtual int code() const {return 134;} |
---|
651 | virtual int nFinal() const {return 3;} |
---|
652 | virtual string inFlux() const {return "qq";} |
---|
653 | virtual bool isQCD3body() const {return true;} |
---|
654 | |
---|
655 | protected: |
---|
656 | |
---|
657 | // Pick/map a random final state configuration |
---|
658 | int config; |
---|
659 | inline void pickFinal() { config = int( 6 * rndmPtr->flat() ); } |
---|
660 | inline void mapFinal(); |
---|
661 | |
---|
662 | // |M|^2 calculation |
---|
663 | inline double m2Calc(); |
---|
664 | |
---|
665 | // Kinematic configuration |
---|
666 | Vec4 pCM[5]; |
---|
667 | |
---|
668 | // Four-products |
---|
669 | double s, t, u, sp, tp, up; |
---|
670 | |
---|
671 | // Cross section |
---|
672 | double sigma; |
---|
673 | |
---|
674 | }; |
---|
675 | |
---|
676 | //========================================================================== |
---|
677 | |
---|
678 | // A derived class for q qbar -> q' qbar' g |
---|
679 | // Derived from Sigma3qq2qqgDiff |
---|
680 | |
---|
681 | class Sigma3qqbar2qqbargDiff : public Sigma3qq2qqgDiff { |
---|
682 | |
---|
683 | public: |
---|
684 | |
---|
685 | // Constructor. |
---|
686 | Sigma3qqbar2qqbargDiff() {} |
---|
687 | |
---|
688 | // Initialize process. |
---|
689 | virtual void initProc(); |
---|
690 | |
---|
691 | // Calculate flavour-independent parts of cross section. |
---|
692 | virtual void sigmaKin(); |
---|
693 | |
---|
694 | // Evaluate d(sigmaHat)/d(tHat). |
---|
695 | virtual double sigmaHat() {return sigma;} |
---|
696 | |
---|
697 | // Select flavour, colour and anticolour. |
---|
698 | virtual void setIdColAcol(); |
---|
699 | |
---|
700 | // Info on the subprocess. |
---|
701 | virtual string name() const {return "q qbar -> q' qbar' g";} |
---|
702 | virtual int code() const {return 136;} |
---|
703 | virtual int nFinal() const {return 3;} |
---|
704 | virtual string inFlux() const {return "qqbarSame";} |
---|
705 | virtual bool isQCD3body() const {return true;} |
---|
706 | |
---|
707 | private: |
---|
708 | |
---|
709 | // Number of quarks to be considered in massless approximation. |
---|
710 | int nQuarkNew; |
---|
711 | |
---|
712 | }; |
---|
713 | |
---|
714 | //========================================================================== |
---|
715 | |
---|
716 | // A derived class for q g -> q q' qbar' |
---|
717 | // Derived from Sigma3qq2qqgDiff |
---|
718 | |
---|
719 | class Sigma3qg2qqqbarDiff : public Sigma3qq2qqgDiff { |
---|
720 | |
---|
721 | public: |
---|
722 | |
---|
723 | // Constructor. |
---|
724 | Sigma3qg2qqqbarDiff() {} |
---|
725 | |
---|
726 | // Initialize process. |
---|
727 | virtual void initProc(); |
---|
728 | |
---|
729 | // Calculate flavour-independent parts of cross section. |
---|
730 | virtual void sigmaKin(); |
---|
731 | |
---|
732 | // Evaluate d(sigmaHat)/d(tHat). |
---|
733 | virtual double sigmaHat(); |
---|
734 | |
---|
735 | // Select flavour, colour and anticolour. |
---|
736 | virtual void setIdColAcol(); |
---|
737 | |
---|
738 | // Info on the subprocess. |
---|
739 | virtual string name() const {return "q g -> q q' qbar'";} |
---|
740 | virtual int code() const {return 139;} |
---|
741 | virtual int nFinal() const {return 3;} |
---|
742 | virtual string inFlux() const {return "qg";} |
---|
743 | virtual bool isQCD3body() const {return true;} |
---|
744 | |
---|
745 | private: |
---|
746 | |
---|
747 | // Number of quarks to be considered in massless approximation. |
---|
748 | int nQuarkNew; |
---|
749 | |
---|
750 | // gq and qg incoming |
---|
751 | double sigma[2]; |
---|
752 | |
---|
753 | }; |
---|
754 | |
---|
755 | //========================================================================== |
---|
756 | |
---|
757 | // A derived class for q q -> q q g |
---|
758 | |
---|
759 | class Sigma3qq2qqgSame : public Sigma3Process { |
---|
760 | |
---|
761 | public: |
---|
762 | |
---|
763 | // Constructor. |
---|
764 | Sigma3qq2qqgSame() {} |
---|
765 | |
---|
766 | // Calculate flavour-independent parts of cross section. |
---|
767 | virtual void sigmaKin(); |
---|
768 | |
---|
769 | // Evaluate d(sigmaHat)/d(tHat). |
---|
770 | virtual double sigmaHat(); |
---|
771 | |
---|
772 | // Select flavour, colour and anticolour. |
---|
773 | virtual void setIdColAcol(); |
---|
774 | |
---|
775 | // Info on the subprocess. |
---|
776 | virtual string name() const |
---|
777 | {return "q(bar) q(bar) -> q(bar) q(bar) g";} |
---|
778 | virtual int code() const {return 135;} |
---|
779 | virtual int nFinal() const {return 3;} |
---|
780 | virtual string inFlux() const {return "qq";} |
---|
781 | virtual bool isQCD3body() const {return true;} |
---|
782 | |
---|
783 | protected: |
---|
784 | |
---|
785 | // Pick/map a random final state configuration |
---|
786 | int config; |
---|
787 | inline void pickFinal() { config = int( 6 * rndmPtr->flat() ); } |
---|
788 | inline void mapFinal(); |
---|
789 | |
---|
790 | // |M|^2 calculation |
---|
791 | inline double m2Calc(); |
---|
792 | |
---|
793 | // Kinematic configuration |
---|
794 | Vec4 pCM[5]; |
---|
795 | |
---|
796 | // Four-products |
---|
797 | double s, t, u, sp, tp, up; |
---|
798 | double ssp, ttp, uup, s_sp, t_tp, u_up; |
---|
799 | |
---|
800 | // Cross section |
---|
801 | double sigma; |
---|
802 | |
---|
803 | }; |
---|
804 | |
---|
805 | //========================================================================== |
---|
806 | |
---|
807 | // A derived class for q q -> q q g |
---|
808 | // Derived from Sigma3qq2qqgSame |
---|
809 | |
---|
810 | class Sigma3qqbar2qqbargSame : public Sigma3qq2qqgSame { |
---|
811 | |
---|
812 | public: |
---|
813 | |
---|
814 | // Constructor. |
---|
815 | Sigma3qqbar2qqbargSame() {} |
---|
816 | |
---|
817 | // Calculate flavour-independent parts of cross section. |
---|
818 | virtual void sigmaKin(); |
---|
819 | |
---|
820 | // Evaluate d(sigmaHat)/d(tHat). |
---|
821 | virtual double sigmaHat() {return sigma;} |
---|
822 | |
---|
823 | // Select flavour, colour and anticolour. |
---|
824 | virtual void setIdColAcol(); |
---|
825 | |
---|
826 | // Info on the subprocess. |
---|
827 | virtual string name() const {return "q qbar -> q qbar g";} |
---|
828 | virtual int code() const {return 137;} |
---|
829 | virtual int nFinal() const {return 3;} |
---|
830 | virtual string inFlux() const {return "qqbarSame";} |
---|
831 | virtual bool isQCD3body() const {return true;} |
---|
832 | |
---|
833 | private: |
---|
834 | |
---|
835 | }; |
---|
836 | |
---|
837 | //========================================================================== |
---|
838 | |
---|
839 | // A derived class for q g -> q qbar q; same flavour. |
---|
840 | // Derived from Sigma3qq2qqgSame |
---|
841 | |
---|
842 | class Sigma3qg2qqqbarSame : public Sigma3qq2qqgSame { |
---|
843 | |
---|
844 | public: |
---|
845 | |
---|
846 | // Constructor. |
---|
847 | Sigma3qg2qqqbarSame() {} |
---|
848 | |
---|
849 | // Calculate flavour-independent parts of cross section. |
---|
850 | virtual void sigmaKin(); |
---|
851 | |
---|
852 | // Evaluate d(sigmaHat)/d(tHat). |
---|
853 | virtual double sigmaHat(); |
---|
854 | |
---|
855 | // Select flavour, colour and anticolour. |
---|
856 | virtual void setIdColAcol(); |
---|
857 | |
---|
858 | // Info on the subprocess. |
---|
859 | virtual string name() const {return "q g -> q q qbar";} |
---|
860 | virtual int code() const {return 140;} |
---|
861 | virtual int nFinal() const {return 3;} |
---|
862 | virtual string inFlux() const {return "qg";} |
---|
863 | virtual bool isQCD3body() const {return true;} |
---|
864 | |
---|
865 | private: |
---|
866 | |
---|
867 | // gq and qg incoming |
---|
868 | double sigma[2]; |
---|
869 | |
---|
870 | }; |
---|
871 | |
---|
872 | //========================================================================== |
---|
873 | |
---|
874 | } // end namespace Pythia8 |
---|
875 | |
---|
876 | #endif // Pythia8_SigmaQCD_H |
---|