[u/mrichter/AliRoot.git] / PYTHIA8 / pythia8175 / xmldoc / CompositenessProcesses.xml

<chapter name="Compositeness Processes">

<h2>Compositeness Processes</h2>

Compositeness scenarios may give rise to sharp resonances of excited 
quarks and leptons. An excited copy of the first generation is 
implemented, consisting of spin 1/2 particles. The possibility of 
contact interactions between SM fermions is also implemented in the 
context of <ei>2 -> 2</ei> quark or fermion-lepton scattering. 

<p/>  
Related to excited fermions, the current implementation contains gauge 
interaction production by quark-gluon fusion or lepton-photon fusion 
and contact interaction production by quark-quark or quark-antiquark 
scattering. For both the <ei>2 -> 1</ei> and <ei>2 -> 2</ei> processes 
a non-trivial angular dependence is included in the decay, however, 
only decays into gauge bosons are supported, i.e. not decays through 
contact interactions. In additions to the compositeness scale and couplings 
listed below, you are expected to change the excited-fermion masses in 
accordance with what is desired. See <ref>Bau90</ref> for conventions.

<p/>
The contact interactions are implemented according to <ref>Eic83</ref>. 
The processes include the SM contributions as well as interference. 
For this reason the processes below converge toward the SM equivalents 
when the contact interaction contributions are close to zero, e.g. 
<code>HardQCD:qq2qq</code> and <code>HardQCD:qqbar2qqbarNew</code> in 
the case of quark scattering. 

<h3>Excited fermions, production processes</h3>

A few different production processes have been implemented, which normally 
would not overlap and therefore could be run together.

<flag name="ExcitedFermion:all" default="off">
Common switch for the group of implemented processes that produce an
excited fermion.
</flag>

<flag name="ExcitedFermion:dg2dStar" default="off">
Scatterings <ei>d g -> d^*</ei>. 
Code 4001.
</flag>

<flag name="ExcitedFermion:ug2uStar" default="off">
Scatterings <ei>u g -> u^*</ei>. 
Code 4002.
</flag>

<flag name="ExcitedFermion:sg2sStar" default="off">
Scatterings <ei>s g -> s^*</ei>. 
Code 4003.
</flag>

<flag name="ExcitedFermion:cg2cStar" default="off">
Scatterings <ei>c g -> c^*</ei>. 
Code 4004.
</flag>

<flag name="ExcitedFermion:bg2bStar" default="off">
Scatterings <ei>b g -> b^*</ei>. 
Code 4005.
</flag>

<flag name="ExcitedFermion:egm2eStar" default="off">
Scatterings <ei>e gamma -> e^*</ei>. 
Code 4011.
</flag>

<flag name="ExcitedFermion:mugm2muStar" default="off">
Scatterings <ei>mu gamma -> mu^*</ei>. 
Code 4013.
</flag>

<flag name="ExcitedFermion:taugm2tauStar" default="off">
Scatterings <ei>tau gamma -> tau^*</ei>. 
Code 4015.
</flag>

<flag name="ExcitedFermion:qq2dStarq" default="off">
Scatterings <ei>q q(bar) -> d^* q(bar)</ei>. 
Code 4021.
</flag>

<flag name="ExcitedFermion:qq2uStarq" default="off">
Scatterings <ei>q q(bar) -> u^* q(bar)</ei>. 
Code 4022.
</flag>

<flag name="ExcitedFermion:qq2sStarq" default="off">
Scatterings <ei>q q(bar) -> s^* q(bar)</ei>. 
Code 4023.
</flag>

<flag name="ExcitedFermion:qq2cStarq" default="off">
Scatterings <ei>q q(bar) -> c^* q(bar)</ei>. 
Code 4024.
</flag>

<flag name="ExcitedFermion:qq2bStarq" default="off">
Scatterings <ei>q q(bar) -> b^* q(bar)</ei>. 
Code 4025.
</flag>

<flag name="ExcitedFermion:qqbar2eStare" default="off">
Scatterings <ei>q qbar -> e^*+- e^-+</ei>. 
Code 4031.
</flag>

<flag name="ExcitedFermion:qqbar2nueStarnue" default="off">
Scatterings <ei>q qbar -> nu_e^* nu_ebar</ei>. 
Code 4032.
</flag>

<flag name="ExcitedFermion:qqbar2muStarmu" default="off">
Scatterings <ei>q qbar -> mu^*+- mu^-+</ei>. 
Code 4033.
</flag>

<flag name="ExcitedFermion:qqbar2numuStarnumu" default="off">
Scatterings <ei>q qbar -> nu_mu^* nu_mubar</ei>. 
Code 4034.
</flag>

<flag name="ExcitedFermion:qqbar2tauStartau" default="off">
Scatterings <ei>q qbar -> tau^*+- tau^-+</ei>. 
Code 4035.
</flag>

<flag name="ExcitedFermion:qqbar2nutauStarnutau" default="off">
Scatterings <ei>q qbar -> nu_tau^* nu_taubar</ei>. 
Code 4036.
</flag>

<h3>Excited fermions, parameters</h3>

The basic couplings of the model are

<parm name="ExcitedFermion:Lambda" default="1000." min="100.">
Compositeness scale <ei>Lambda</ei> in GeV.
</parm>

<parm name="ExcitedFermion:coupF" default="1.0" min="0.0">
Strength <ei>f</ei> of the <ei>SU(2)</ei> coupling.
</parm>

<parm name="ExcitedFermion:coupFprime" default="1.0" min="0.0">
Strength <ei>f'</ei> of the <ei>U(1)</ei> coupling.
</parm>

<parm name="ExcitedFermion:coupFcol" default="1.0" min="0.0">
Strength <ei>f_c</ei> of the <ei>SU(3)</ei> coupling.
</parm>

<h3>Contact interactions, production processes</h3>

The processes including contact interactions are

<flag name="ContactInteractions:QCqq2qq" default="off">
Scatterings <ei>q q -> q q</ei> including contact interactions. 
Code 4201.
</flag>

<flag name="ContactInteractions:QCqqbar2qqbar" default="off">
Scatterings <ei>q qbar -> q' qbar'</ei> including contact interactions. 
Code 4202.
</flag>

<flag name="ContactInteractions:QCffbar2eebar" default="off">
Scatterings <ei>f fbar -> e- e+</ei> including contact interactions. 
Code 4203.
</flag>

<flag name="ContactInteractions:QCffbar2mumubar" default="off">
Scatterings <ei>f fbar -> mu- mu+</ei> including contact interactions. 
Code 4204.
</flag>

<flag name="ContactInteractions:QCffbar2tautaubar" default="off">
Scatterings <ei>f fbar -> tau- tau+</ei> including contact interactions. 
Code 4205.
</flag>

<h3>Contact interactions, parameters</h3>

<modeopen name="ContactInteractions:nQuarkNew" default="3" min="0" max="5">
Number of allowed outgoing new quark flavours in the above
<ei>q qbar -> q' qbar'</ei> process. Similar to <ei>HardQCD:nQuarkNew</ei> 
for the QCD processes.
</modeopen>

<parm name="ContactInteractions:Lambda" default="1000." min="100.">
Compositeness scale <ei>Lambda</ei> in GeV.
</parm>

<modepick name="ContactInteractions:etaLL" default="0" min="-1" max="1">
Helicity parameter. 
<option value="1"></option>
<option value="0"></option>
<option value="-1"></option>
</modepick>

<modepick name="ContactInteractions:etaRR" default="0" min="-1" max="1">
Helicity parameter. 
<option value="1"></option>
<option value="0"></option>
<option value="-1"></option>
</modepick>

<modepick name="ContactInteractions:etaLR" default="0" min="-1" max="1">
Helicity parameter. 
<option value="1"></option>
<option value="0"></option>
<option value="-1"></option>
</modepick>

</chapter>

<!-- Copyright (C) 2013 Torbjorn Sjostrand -->
Commit	Line	Data
c6b60c38	1	<chapter name="Compositeness Processes">
	2
	3	<h2>Compositeness Processes</h2>
	4
	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 SM fermions is also implemented in the
	9	context of <ei>2 -> 2</ei> quark or fermion-lepton scattering.
	10
	11	<p/>
	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. For both the <ei>2 -> 1</ei> and <ei>2 -> 2</ei> processes
	16	a non-trivial angular dependence is included in the decay, however,
	17	only decays into gauge bosons are supported, i.e. not decays through
	18	contact interactions. In additions to the compositeness scale and couplings
	19	listed below, you are expected to change the excited-fermion masses in
	20	accordance with what is desired. See <ref>Bau90</ref> for conventions.
	21
	22	<p/>
	23	The contact interactions are implemented according to <ref>Eic83</ref>.
	24	The processes include the SM contributions as well as interference.
	25	For this reason the processes below converge toward the SM equivalents
	26	when the contact interaction contributions are close to zero, e.g.
	27	<code>HardQCD:qq2qq</code> and <code>HardQCD:qqbar2qqbarNew</code> in
	28	the case of quark scattering.
	29
	30	<h3>Excited fermions, production processes</h3>
	31
	32	A few different production processes have been implemented, which normally
	33	would not overlap and therefore could be run together.
	34
	35	<flag name="ExcitedFermion:all" default="off">
	36	Common switch for the group of implemented processes that produce an
	37	excited fermion.
	38	</flag>
	39
	40	<flag name="ExcitedFermion:dg2dStar" default="off">
	41	Scatterings <ei>d g -> d^*</ei>.
	42	Code 4001.
	43	</flag>
	44
	45	<flag name="ExcitedFermion:ug2uStar" default="off">
	46	Scatterings <ei>u g -> u^*</ei>.
	47	Code 4002.
	48	</flag>
	49
	50	<flag name="ExcitedFermion:sg2sStar" default="off">
	51	Scatterings <ei>s g -> s^*</ei>.
	52	Code 4003.
	53	</flag>
	54
	55	<flag name="ExcitedFermion:cg2cStar" default="off">
	56	Scatterings <ei>c g -> c^*</ei>.
	57	Code 4004.
	58	</flag>
	59
	60	<flag name="ExcitedFermion:bg2bStar" default="off">
	61	Scatterings <ei>b g -> b^*</ei>.
	62	Code 4005.
	63	</flag>
	64
65	<flag name="ExcitedFermion:egm2eStar" default="off">
66	Scatterings <ei>e gamma -> e^*</ei>.
67	Code 4011.
68	</flag>
69
70	<flag name="ExcitedFermion:mugm2muStar" default="off">
71	Scatterings <ei>mu gamma -> mu^*</ei>.
72	Code 4013.
73	</flag>
74
75	<flag name="ExcitedFermion:taugm2tauStar" default="off">
76	Scatterings <ei>tau gamma -> tau^*</ei>.
77	Code 4015.
78	</flag>
79
80	<flag name="ExcitedFermion:qq2dStarq" default="off">
81	Scatterings <ei>q q(bar) -> d^* q(bar)</ei>.
82	Code 4021.
83	</flag>
84
85	<flag name="ExcitedFermion:qq2uStarq" default="off">
86	Scatterings <ei>q q(bar) -> u^* q(bar)</ei>.
87	Code 4022.
88	</flag>
89
90	<flag name="ExcitedFermion:qq2sStarq" default="off">
91	Scatterings <ei>q q(bar) -> s^* q(bar)</ei>.
92	Code 4023.
93	</flag>
94
95	<flag name="ExcitedFermion:qq2cStarq" default="off">
96	Scatterings <ei>q q(bar) -> c^* q(bar)</ei>.
97	Code 4024.
98	</flag>
99
100	<flag name="ExcitedFermion:qq2bStarq" default="off">
101	Scatterings <ei>q q(bar) -> b^* q(bar)</ei>.
102	Code 4025.
103	</flag>
104
105	<flag name="ExcitedFermion:qqbar2eStare" default="off">
106	Scatterings <ei>q qbar -> e^*+- e^-+</ei>.
107	Code 4031.
108	</flag>
109
110	<flag name="ExcitedFermion:qqbar2nueStarnue" default="off">
111	Scatterings <ei>q qbar -> nu_e^* nu_ebar</ei>.
112	Code 4032.
113	</flag>
114
115	<flag name="ExcitedFermion:qqbar2muStarmu" default="off">
116	Scatterings <ei>q qbar -> mu^*+- mu^-+</ei>.
117	Code 4033.
118	</flag>
119
120	<flag name="ExcitedFermion:qqbar2numuStarnumu" default="off">
121	Scatterings <ei>q qbar -> nu_mu^* nu_mubar</ei>.
122	Code 4034.
123	</flag>
124
125	<flag name="ExcitedFermion:qqbar2tauStartau" default="off">
126	Scatterings <ei>q qbar -> tau^*+- tau^-+</ei>.
127	Code 4035.
128	</flag>
129
130	<flag name="ExcitedFermion:qqbar2nutauStarnutau" default="off">
131	Scatterings <ei>q qbar -> nu_tau^* nu_taubar</ei>.
132	Code 4036.
133	</flag>
134
135	<h3>Excited fermions, parameters</h3>
136
137	The basic couplings of the model are
138
139	<parm name="ExcitedFermion:Lambda" default="1000." min="100.">
140	Compositeness scale <ei>Lambda</ei> in GeV.
141	</parm>
142
143	<parm name="ExcitedFermion:coupF" default="1.0" min="0.0">
144	Strength <ei>f</ei> of the <ei>SU(2)</ei> coupling.
145	</parm>
146
147	<parm name="ExcitedFermion:coupFprime" default="1.0" min="0.0">
148	Strength <ei>f'</ei> of the <ei>U(1)</ei> coupling.
149	</parm>
150
151	<parm name="ExcitedFermion:coupFcol" default="1.0" min="0.0">
152	Strength <ei>f_c</ei> of the <ei>SU(3)</ei> coupling.
153	</parm>
154
155	<h3>Contact interactions, production processes</h3>
156
157	The processes including contact interactions are
158
159	<flag name="ContactInteractions:QCqq2qq" default="off">
160	Scatterings <ei>q q -> q q</ei> including contact interactions.
161	Code 4201.
162	</flag>
163
164	<flag name="ContactInteractions:QCqqbar2qqbar" default="off">
165	Scatterings <ei>q qbar -> q' qbar'</ei> including contact interactions.
166	Code 4202.
167	</flag>
168
169	<flag name="ContactInteractions:QCffbar2eebar" default="off">
170	Scatterings <ei>f fbar -> e- e+</ei> including contact interactions.
171	Code 4203.
172	</flag>
173
174	<flag name="ContactInteractions:QCffbar2mumubar" default="off">
175	Scatterings <ei>f fbar -> mu- mu+</ei> including contact interactions.
176	Code 4204.
177	</flag>
178
179	<flag name="ContactInteractions:QCffbar2tautaubar" default="off">
180	Scatterings <ei>f fbar -> tau- tau+</ei> including contact interactions.
181	Code 4205.
182	</flag>
183
184	<h3>Contact interactions, parameters</h3>
185
186	<modeopen name="ContactInteractions:nQuarkNew" default="3" min="0" max="5">
187	Number of allowed outgoing new quark flavours in the above
188	<ei>q qbar -> q' qbar'</ei> process. Similar to <ei>HardQCD:nQuarkNew</ei>
189	for the QCD processes.
190	</modeopen>
191
192	<parm name="ContactInteractions:Lambda" default="1000." min="100.">
193	Compositeness scale <ei>Lambda</ei> in GeV.
194	</parm>
195
196	<modepick name="ContactInteractions:etaLL" default="0" min="-1" max="1">
197	Helicity parameter.
198	<option value="1"></option>
199	<option value="0"></option>
200	<option value="-1"></option>
201	</modepick>
202
203	<modepick name="ContactInteractions:etaRR" default="0" min="-1" max="1">
204	Helicity parameter.
205	<option value="1"></option>
206	<option value="0"></option>
207	<option value="-1"></option>
208	</modepick>
209
210	<modepick name="ContactInteractions:etaLR" default="0" min="-1" max="1">
211	Helicity parameter.
212	<option value="1"></option>
213	<option value="0"></option>
214	<option value="-1"></option>
215	</modepick>
216
217	</chapter>
218
219	<!-- Copyright (C) 2013 Torbjorn Sjostrand -->
220