1 | <chapter name="Compositeness Processes"> |
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2 | |
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3 | <h2>Compositeness Processes</h2> |
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4 | |
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5 | Compositeness scenarios may give rise to sharp resonances of excited |
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6 | quarks and leptons. An excited copy of the first generation is |
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7 | implemented, consisting of spin 1/2 particles. The possibility of |
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8 | contact interactions between SM fermions is also implemented in the |
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9 | context of <ei>2 -> 2</ei> quark or fermion-lepton scattering. |
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10 | |
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11 | <p/> |
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12 | Related to excited fermions, the current implementation contains gauge |
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13 | interaction production by quark-gluon fusion or lepton-photon fusion |
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14 | and contact interaction production by quark-quark or quark-antiquark |
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15 | scattering. For both the <ei>2 -> 1</ei> and <ei>2 -> 2</ei> processes |
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16 | a non-trivial angular dependence is included in the decay, however, |
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17 | only decays into gauge bosons are supported, i.e. not decays through |
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18 | contact interactions. In additions to the compositness scale and couplings |
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19 | listed below, you are expected to change the excited-fermion masses in |
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20 | accordance with what is desired. See <ref>Bau90</ref> for conventions. |
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21 | |
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22 | <p/> |
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23 | The contact interactions are implemented according to <ref>Eic83</ref>. |
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24 | The processes include the SM contributions as well as interference. |
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25 | For this reason the processes below converge toward the SM equivalents |
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26 | when the contact interaction contributions are close to zero, e.g. |
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27 | <code>HardQCD:qq2qq</code> and <code>HardQCD:qqbar2qqbarNew</code> in |
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28 | the case of quark scattering. |
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29 | |
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30 | <h3>Excited fermions, production processes</h3> |
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31 | |
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32 | A few different production processes have been implemented, which normally |
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33 | would not overlap and therefore could be run together. |
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34 | |
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35 | <flag name="ExcitedFermion:all" default="off"> |
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36 | Common switch for the group of implemented processes that produce an |
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37 | excited fermion. |
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38 | </flag> |
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39 | |
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40 | <flag name="ExcitedFermion:dg2dStar" default="off"> |
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41 | Scatterings <ei>d g -> d^*</ei>. |
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42 | Code 4001. |
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43 | </flag> |
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44 | |
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45 | <flag name="ExcitedFermion:ug2uStar" default="off"> |
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46 | Scatterings <ei>u g -> u^*</ei>. |
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47 | Code 4002. |
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48 | </flag> |
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49 | |
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50 | <flag name="ExcitedFermion:sg2sStar" default="off"> |
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51 | Scatterings <ei>s g -> s^*</ei>. |
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52 | Code 4003. |
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53 | </flag> |
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54 | |
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55 | <flag name="ExcitedFermion:cg2cStar" default="off"> |
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56 | Scatterings <ei>c g -> c^*</ei>. |
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57 | Code 4004. |
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58 | </flag> |
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59 | |
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60 | <flag name="ExcitedFermion:bg2bStar" default="off"> |
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61 | Scatterings <ei>b g -> b^*</ei>. |
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62 | Code 4005. |
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63 | </flag> |
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64 | |
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65 | <flag name="ExcitedFermion:egm2eStar" default="off"> |
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66 | Scatterings <ei>e gamma -> e^*</ei>. |
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67 | Code 4011. |
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68 | </flag> |
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69 | |
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70 | <flag name="ExcitedFermion:mugm2muStar" default="off"> |
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71 | Scatterings <ei>mu gamma -> mu^*</ei>. |
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72 | Code 4013. |
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73 | </flag> |
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74 | |
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75 | <flag name="ExcitedFermion:taugm2tauStar" default="off"> |
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76 | Scatterings <ei>tau gamma -> tau^*</ei>. |
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77 | Code 4015. |
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78 | </flag> |
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79 | |
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80 | <flag name="ExcitedFermion:qq2dStarq" default="off"> |
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81 | Scatterings <ei>q q(bar) -> d^* q(bar)</ei>. |
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82 | Code 4021. |
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83 | </flag> |
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84 | |
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85 | <flag name="ExcitedFermion:qq2uStarq" default="off"> |
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86 | Scatterings <ei>q q(bar) -> u^* q(bar)</ei>. |
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87 | Code 4022. |
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88 | </flag> |
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89 | |
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90 | <flag name="ExcitedFermion:qq2sStarq" default="off"> |
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91 | Scatterings <ei>q q(bar) -> s^* q(bar)</ei>. |
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92 | Code 4023. |
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93 | </flag> |
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94 | |
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95 | <flag name="ExcitedFermion:qq2cStarq" default="off"> |
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96 | Scatterings <ei>q q(bar) -> c^* q(bar)</ei>. |
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97 | Code 4024. |
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98 | </flag> |
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99 | |
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100 | <flag name="ExcitedFermion:qq2bStarq" default="off"> |
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101 | Scatterings <ei>q q(bar) -> b^* q(bar)</ei>. |
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102 | Code 4025. |
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103 | </flag> |
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104 | |
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105 | <flag name="ExcitedFermion:qqbar2eStare" default="off"> |
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106 | Scatterings <ei>q qbar -> e^*+- e^-+</ei>. |
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107 | Code 4031. |
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108 | </flag> |
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109 | |
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110 | <flag name="ExcitedFermion:qqbar2nueStarnue" default="off"> |
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111 | Scatterings <ei>q qbar -> nu_e^* nu_ebar</ei>. |
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112 | Code 4032. |
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113 | </flag> |
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114 | |
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115 | <flag name="ExcitedFermion:qqbar2muStarmu" default="off"> |
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116 | Scatterings <ei>q qbar -> mu^*+- mu^-+</ei>. |
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117 | Code 4033. |
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118 | </flag> |
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119 | |
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120 | <flag name="ExcitedFermion:qqbar2numuStarnumu" default="off"> |
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121 | Scatterings <ei>q qbar -> nu_mu^* nu_mubar</ei>. |
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122 | Code 4034. |
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123 | </flag> |
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124 | |
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125 | <flag name="ExcitedFermion:qqbar2tauStartau" default="off"> |
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126 | Scatterings <ei>q qbar -> tau^*+- tau^-+</ei>. |
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127 | Code 4035. |
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128 | </flag> |
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129 | |
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130 | <flag name="ExcitedFermion:qqbar2nutauStarnutau" default="off"> |
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131 | Scatterings <ei>q qbar -> nu_tau^* nu_taubar</ei>. |
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132 | Code 4036. |
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133 | </flag> |
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134 | |
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135 | <h3>Excited fermions, parameters</h3> |
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136 | |
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137 | The basic couplings of the model are |
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138 | |
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139 | <parm name="ExcitedFermion:Lambda" default="1000." min="100."> |
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140 | Compositeness scale <ei>Lambda</ei> in GeV. |
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141 | </parm> |
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142 | |
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143 | <parm name="ExcitedFermion:coupF" default="1.0" min="0.0"> |
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144 | Strength <ei>f</ei> of the <ei>SU(2)</ei> coupling. |
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145 | </parm> |
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146 | |
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147 | <parm name="ExcitedFermion:coupFprime" default="1.0" min="0.0"> |
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148 | Strength <ei>f'</ei> of the <ei>U(1)</ei> coupling. |
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149 | </parm> |
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150 | |
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151 | <parm name="ExcitedFermion:coupFcol" default="1.0" min="0.0"> |
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152 | Strength <ei>f_c</ei> of the <ei>SU(3)</ei> coupling. |
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153 | </parm> |
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154 | |
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155 | <h3>Contact interactions, production processes</h3> |
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156 | |
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157 | The processes including contact interactions are |
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158 | |
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159 | <flag name="ContactInteractions:QCqq2qq" default="off"> |
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160 | Scatterings <ei>q q -> q q</ei> including contact interactions. |
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161 | Code 4201. |
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162 | </flag> |
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163 | |
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164 | <flag name="ContactInteractions:QCqqbar2qqbar" default="off"> |
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165 | Scatterings <ei>q qbar -> q' qbar'</ei> including contact interactions. |
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166 | Code 4202. |
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167 | </flag> |
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168 | |
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169 | <flag name="ContactInteractions:QCffbar2eebar" default="off"> |
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170 | Scatterings <ei>f fbar -> e- e+</ei> including contact interactions. |
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171 | Code 4203. |
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172 | </flag> |
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173 | |
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174 | <flag name="ContactInteractions:QCffbar2mumubar" default="off"> |
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175 | Scatterings <ei>f fbar -> mu- mu+</ei> including contact interactions. |
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176 | Code 4204. |
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177 | </flag> |
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178 | |
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179 | <flag name="ContactInteractions:QCffbar2tautaubar" default="off"> |
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180 | Scatterings <ei>f fbar -> tau- tau+</ei> including contact interactions. |
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181 | Code 4205. |
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182 | </flag> |
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183 | |
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184 | <h3>Contact interactions, parameters</h3> |
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185 | |
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186 | <modeopen name="ContactInteractions:nQuarkNew" default="3" min="0" max="5"> |
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187 | Number of allowed outgoing new quark flavours in the above |
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188 | <ei>q qbar -> q' qbar'</ei> process. Similar to <ei>HardQCD:nQuarkNew</ei> |
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189 | for the QCD processes. |
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190 | </modeopen> |
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191 | |
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192 | <parm name="ContactInteractions:Lambda" default="1000." min="100."> |
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193 | Compositeness scale <ei>Lambda</ei> in GeV. |
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194 | </parm> |
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195 | |
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196 | <modepick name="ContactInteractions:etaLL" default="0" min="-1" max="1"> |
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197 | Helicity parameter. |
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198 | <option value="1"></option> |
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199 | <option value="0"></option> |
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200 | <option value="-1"></option> |
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201 | </modepick> |
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202 | |
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203 | <modepick name="ContactInteractions:etaRR" default="0" min="-1" max="1"> |
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204 | Helicity parameter. |
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205 | <option value="1"></option> |
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206 | <option value="0"></option> |
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207 | <option value="-1"></option> |
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208 | </modepick> |
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209 | |
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210 | <modepick name="ContactInteractions:etaLR" default="0" min="-1" max="1"> |
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211 | Helicity parameter. |
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212 | <option value="1"></option> |
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213 | <option value="0"></option> |
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214 | <option value="-1"></option> |
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215 | </modepick> |
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216 | |
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217 | </chapter> |
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218 | |
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219 | <!-- Copyright (C) 2012 Torbjorn Sjostrand --> |
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220 | |
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