1 <chapter name="Compositeness Processes">
3 <h2>Compositeness Processes</h2>
5 Compositeness scenarios may give rise to sharp resonances of excited
6 quarks and leptons. An excited copy of the first generation is
7 implemented, consisting of spin 1/2 particles. The possibility of
8 contact interactions between quarks is also implemented in the context
9 of <ei>2 -> 2</ei> quark scattering.
12 Related to excited fermions, the current implementation contains gauge
13 interaction production by quark-gluon fusion or lepton-photon fusion
14 and contact interaction production by quark-quark or quark-antiquark
15 scattering. In additions to the compositness scale and couplings listed
16 below, you are expected to change the excited-fermion masses in accordance
17 with what is desired. See <ref>Bau90</ref> for conventions.
20 A non-trivial angular dependence is included in the decay for the
21 <ei>2 -> 1</ei> processes, but has not been included for the
25 The quark contact interactions are implemented according to
26 <ref>Eic83</ref>. The processes include the QCD contributions
27 as well as interference. For this reason the two processes
28 below converge toward, <code>HardQCD:qq2qq</code> and
29 <code>HardQCD:qqbar2qqbarNew</code>, when the contact interaction
30 contributions are close to zero.
32 <h3>Excited fermions, production processes</h3>
34 A few different production processes have been implemented, which normally
35 would not overlap and therefore could be run together.
37 <flag name="ExcitedFermion:all" default="off">
38 Common switch for the group of implemented processes that produce an
42 <flag name="ExcitedFermion:dg2dStar" default="off">
43 Scatterings <ei>d g -> d^*</ei>.
47 <flag name="ExcitedFermion:ug2uStar" default="off">
48 Scatterings <ei>u g -> u^*</ei>.
52 <flag name="ExcitedFermion:sg2sStar" default="off">
53 Scatterings <ei>s g -> s^*</ei>.
57 <flag name="ExcitedFermion:cg2cStar" default="off">
58 Scatterings <ei>c g -> c^*</ei>.
62 <flag name="ExcitedFermion:bg2bStar" default="off">
63 Scatterings <ei>b g -> b^*</ei>.
67 <flag name="ExcitedFermion:egm2eStar" default="off">
68 Scatterings <ei>e gamma -> e^*</ei>.
72 <flag name="ExcitedFermion:mugm2muStar" default="off">
73 Scatterings <ei>mu gamma -> mu^*</ei>.
77 <flag name="ExcitedFermion:taugm2tauStar" default="off">
78 Scatterings <ei>tau gamma -> tau^*</ei>.
82 <flag name="ExcitedFermion:qq2dStarq" default="off">
83 Scatterings <ei>q q(bar) -> d^* q(bar)</ei>.
87 <flag name="ExcitedFermion:qq2uStarq" default="off">
88 Scatterings <ei>q q(bar) -> u^* q(bar)</ei>.
92 <flag name="ExcitedFermion:qq2sStarq" default="off">
93 Scatterings <ei>q q(bar) -> s^* q(bar)</ei>.
97 <flag name="ExcitedFermion:qq2cStarq" default="off">
98 Scatterings <ei>q q(bar) -> c^* q(bar)</ei>.
102 <flag name="ExcitedFermion:qq2bStarq" default="off">
103 Scatterings <ei>q q(bar) -> b^* q(bar)</ei>.
107 <flag name="ExcitedFermion:qqbar2eStare" default="off">
108 Scatterings <ei>q qbar -> e^*+- e^-+</ei>.
112 <flag name="ExcitedFermion:qqbar2nueStarnue" default="off">
113 Scatterings <ei>q qbar -> nu_e^* nu_ebar</ei>.
117 <flag name="ExcitedFermion:qqbar2muStarmu" default="off">
118 Scatterings <ei>q qbar -> mu^*+- mu^-+</ei>.
122 <flag name="ExcitedFermion:qqbar2numuStarnumu" default="off">
123 Scatterings <ei>q qbar -> nu_mu^* nu_mubar</ei>.
127 <flag name="ExcitedFermion:qqbar2tauStartau" default="off">
128 Scatterings <ei>q qbar -> tau^*+- tau^-+</ei>.
132 <flag name="ExcitedFermion:qqbar2nutauStarnutau" default="off">
133 Scatterings <ei>q qbar -> nu_tau^* nu_taubar</ei>.
137 <h3>Excited fermions, parameters</h3>
139 The basic couplings of the model are
141 <parm name="ExcitedFermion:Lambda" default="1000." min="100.">
142 Compositeness scale <ei>Lambda</ei> in GeV.
145 <parm name="ExcitedFermion:coupF" default="1.0" min="0.0">
146 Strength <ei>f</ei> of the <ei>SU(2)</ei> coupling.
149 <parm name="ExcitedFermion:coupFprime" default="1.0" min="0.0">
150 Strength <ei>f'</ei> of the <ei>U(1)</ei> coupling.
153 <parm name="ExcitedFermion:coupFcol" default="1.0" min="0.0">
154 Strength <ei>f_c</ei> of the <ei>SU(3)</ei> coupling.
157 <h3>Contact interactions, production processes</h3>
159 The processes including quark contact interactions are
161 <flag name="ContactInteractions:QCqq2qq" default="off">
162 Scatterings <ei>q q -> q q</ei> including contact interactions.
166 <flag name="ContactInteractions:QCqqbar2qqbar" default="off">
167 Scatterings <ei>q qbar -> q' qbar'</ei> including contact interactions.
171 <h3>Contact interactions, parameters</h3>
173 <modeopen name="ContactInteractions:nQuarkNew" default="3" min="0" max="5">
174 Number of allowed outgoing new quark flavours in the above
175 <ei>q qbar -> q' qbar'</ei> process. Similar to <ei>HardQCD:nQuarkNew</ei>
176 for the QCD processes.
179 <parm name="ContactInteractions:Lambda" default="1000." min="100.">
180 Compositeness scale <ei>Lambda</ei> in GeV.
183 <modepick name="ContactInteractions:etaLL" default="0" min="-1" max="1">
185 <option value="1"></option>
186 <option value="0"></option>
187 <option value="-1"></option>
190 <modepick name="ContactInteractions:etaRR" default="0" min="-1" max="1">
192 <option value="1"></option>
193 <option value="0"></option>
194 <option value="-1"></option>
197 <modepick name="ContactInteractions:etaLR" default="0" min="-1" max="1">
199 <option value="1"></option>
200 <option value="0"></option>
201 <option value="-1"></option>
206 <!-- Copyright (C) 2010 Torbjorn Sjostrand -->