Extra-Dimensional Processes
Scenarios with extra dimensions allow a multitude of processes.
Currently the only ones implemented involve the production of an
excited graviton state G^* within a Randall-Sundrum scenario.
This state is assigned PDG code 5000039. Decays into fermion, gluon
and photon pairs are handled with the correct angular distributions,
while other decay channels currently are handled isotropically.
Production processes
There are two lowest-order processes that together normally should be
sufficient for a simulation of G^* production.
flag ExtraDimensionsG*:all
(default = off)
Common switch for the group of lowest-order G^* production
processes, i.e. the two ones below.
flag ExtraDimensionsG*:gg2G*
(default = off)
Scatterings g g -> G^*.
Code 5001.
flag ExtraDimensionsG*:ffbar2G*
(default = off)
Scatterings f fbar -> G^*.
Code 5002.
In addition there are three first-order processes included. These are of
less interest, but can be used for dedicated studies of the high-pT
tail of G^* producton. As usual, it would be doublecounting to
include the lowest-order and first-order processes simultaneously.
Therefore the latter ones are not included with the
ExtraDimensionsG*:all = on option. In this set of processes
all decay angles are assumed istropic.
flag ExtraDimensionsG*:gg2G*g
(default = off)
Scatterings g g -> G^* g.
Code 5003.
flag ExtraDimensionsG*:qg2G*q
(default = off)
Scatterings q g -> G^* q.
Code 5004.
flag ExtraDimensionsG*:qqbar2G*g
(default = off)
Scatterings q qbar -> G^* g.
Code 5005.
Parameters
In the above scenario the main free parameter is the G^* mass,
which is set as usual. In addition there is one further parameter.
parm ExtraDimensionsG*:kappaMG
(default = 0.054; minimum = 0.0)
dimensionless coupling, which enters quadratically in all partial
widths of the G^*. Is
kappa m_G* = sqrt(2) x_1 k / Mbar_Pl,
where x_1 = 3.83 is the first zero of the J_1 Bessel
function and Mbar_Pl is the modified Planck mass.