SETTINGS SAVED TO FILE

"; } else { echo "NO FILE SELECTED YET.. PLEASE DO SO HERE

"; } } ?>

Compositeness Processes

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 2 → 2 quark or fermion-lepton scattering.

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 2 → 1 and 2 → 2 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 [Bau90] for conventions.

The contact interactions are implemented according to [Eic83]. 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. HardQCD:qq2qq and HardQCD:qqbar2qqbarNew in the case of quark scattering.

It should also be noted that the gamma*/Z/Z' production process available with NewGaugeBoson:ffbar2gmZZprime is prepared for pair-production of excited quarks and leptons, assuming the same gauge couplings as for the non-excited fermions. What is missing is the actual decay channels in the list of Z' decay modes, which have to be added by hand, e.g. by
32:addChannel = 1 1. 100 4000001 -4000001
You can use Zprime:gmZmode to decide which gauge boson propagators actually are included in the simulation, and thus e.g. switch off the Z' part of the propagator. You may also want to switch off other decay channels and set the minimal mass to be at the threshold for the studied pair production (or suitably below it, if the excited fermions have a non-negligible width).

Excited fermions, production processes

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

ExcitedFermion:all On Off   (default = off)
Common switch for the group of implemented processes that produce an excited fermion.

ExcitedFermion:dg2dStar On Off   (default = off)
Scatterings d g → d^*. Code 4001.

ExcitedFermion:ug2uStar On Off   (default = off)
Scatterings u g → u^*. Code 4002.

ExcitedFermion:sg2sStar On Off   (default = off)
Scatterings s g → s^*. Code 4003.

ExcitedFermion:cg2cStar On Off   (default = off)
Scatterings c g → c^*. Code 4004.

ExcitedFermion:bg2bStar On Off   (default = off)
Scatterings b g → b^*. Code 4005.

ExcitedFermion:egm2eStar On Off   (default = off)
Scatterings e gamma → e^*. Code 4011.

ExcitedFermion:mugm2muStar On Off   (default = off)
Scatterings mu gamma → mu^*. Code 4013.

ExcitedFermion:taugm2tauStar On Off   (default = off)
Scatterings tau gamma → tau^*. Code 4015.

ExcitedFermion:qq2dStarq On Off   (default = off)
Scatterings q q(bar) → d^* q(bar). Code 4021.

ExcitedFermion:qq2uStarq On Off   (default = off)
Scatterings q q(bar) → u^* q(bar). Code 4022.

ExcitedFermion:qq2sStarq On Off   (default = off)
Scatterings q q(bar) → s^* q(bar). Code 4023.

ExcitedFermion:qq2cStarq On Off   (default = off)
Scatterings q q(bar) → c^* q(bar). Code 4024.

ExcitedFermion:qq2bStarq On Off   (default = off)
Scatterings q q(bar) → b^* q(bar). Code 4025.

ExcitedFermion:qqbar2eStare On Off   (default = off)
Scatterings q qbar → e^*+- e^-+. Code 4031.

ExcitedFermion:qqbar2nueStarnue On Off   (default = off)
Scatterings q qbar → nu_e^* nu_ebar. Code 4032.

ExcitedFermion:qqbar2muStarmu On Off   (default = off)
Scatterings q qbar → mu^*+- mu^-+. Code 4033.

ExcitedFermion:qqbar2numuStarnumu On Off   (default = off)
Scatterings q qbar → nu_mu^* nu_mubar. Code 4034.

ExcitedFermion:qqbar2tauStartau On Off   (default = off)
Scatterings q qbar → tau^*+- tau^-+. Code 4035.

ExcitedFermion:qqbar2nutauStarnutau On Off   (default = off)
Scatterings q qbar → nu_tau^* nu_taubar. Code 4036.

ExcitedFermion:qqbar2eStareStar On Off   (default = off)
Scatterings q qbar → e^*+- e^*-+. Code 4051.

ExcitedFermion:qqbar2nueStarnueStar On Off   (default = off)
Scatterings q qbar → nu_e^* nu_e^*bar. Code 4052.

ExcitedFermion:qqbar2muStarmuStar On Off   (default = off)
Scatterings q qbar → mu^*+- mu^*-+. Code 4053.

ExcitedFermion:qqbar2numuStarnumuStar On Off   (default = off)
Scatterings q qbar → nu_mu^* nu_mu^*bar. Code 4054.

ExcitedFermion:qqbar2tauStartauStar On Off   (default = off)
Scatterings q qbar → tau^*+- tau^*-+. Code 4055.

ExcitedFermion:qqbar2nutauStarnutauStar On Off   (default = off)
Scatterings q qbar → nu_tau^* nu_tau^*bar. Code 4056.

Excited fermions, parameters

The basic couplings of the model are

ExcitedFermion:Lambda   (default = 1000.; minimum = 100.)
Compositeness scale Lambda in GeV.

ExcitedFermion:coupF   (default = 1.0; minimum = 0.0)
Strength f of the SU(2) coupling.

ExcitedFermion:coupFprime   (default = 1.0; minimum = 0.0)
Strength f' of the U(1) coupling.

ExcitedFermion:coupFcol   (default = 1.0; minimum = 0.0)
Strength f_c of the SU(3) coupling.

ExcitedFermion:contactDec   (default = 1.0; minimum = 0.0)
Strength of contact-interaction decay channels, implemented as three-body decays l^* → l f fbar for excited leptons and neutrinos, where unity corresponds to the same normalization as for the production channels.

Contact interactions, production processes

The processes including contact interactions are

ContactInteractions:QCqq2qq On Off   (default = off)
Scatterings q q → q q including contact interactions. Code 4201.

ContactInteractions:QCqqbar2qqbar On Off   (default = off)
Scatterings q qbar → q' qbar' including contact interactions. Code 4202.

ContactInteractions:QCffbar2eebar On Off   (default = off)
Scatterings f fbar → e- e+ including contact interactions. Code 4203.

ContactInteractions:QCffbar2mumubar On Off   (default = off)
Scatterings f fbar → mu- mu+ including contact interactions. Code 4204.

ContactInteractions:QCffbar2tautaubar On Off   (default = off)
Scatterings f fbar → tau- tau+ including contact interactions. Code 4205.

Contact interactions, parameters



ContactInteractions:nQuarkNew   (default = 3; minimum = 0; maximum = 5)
Number of allowed outgoing new quark flavours in the above q qbar → q' qbar' process. Similar to HardQCD:nQuarkNew for the QCD processes.

ContactInteractions:Lambda   (default = 1000.; minimum = 100.)
Compositeness scale Lambda in GeV. Its overall normalization is largely a matter of convention. The choice made here for the q qbar → l- l+ processes is such that the pure contact interaction part of the left-left interactions (i.e. disregarding gamma^*, Z^0 and interference terms) has the form d(sigmaHat)/d(tHat) = pi * uHat^2 / (3 * sHat^2 * Lambda^4). The corresponding part of the q qbar → q' qbar' cross section is a factor 3 larger from colour.

ContactInteractions:etaLL   (default = 0; minimum = -1; maximum = 1)
Helicity parameter.
1 :
0 :
-1 :


ContactInteractions:etaRR   (default = 0; minimum = -1; maximum = 1)
Helicity parameter.
1 :
0 :
-1 :


ContactInteractions:etaLR   (default = 0; minimum = -1; maximum = 1)
Helicity parameter.
1 :
0 :
-1 :
"?>