Extra-Dimensional Processes
 
  - Randall-Sundrum Resonances, production processes
- Randall-Sundrum Resonances, parameters
- TeV^-1 Sized Extra Dimension, production processes
- TeV^-1 Sized Extra Dimension, parameters
- Large Extra Dimensions, production processes
- Large Extra Dimensions, parameters
- Unparticles, production processes
- Unparticles, parameters
Scenarios with extra dimensions (ED) allow a multitude of processes. 
Currently three different categories of processes are implemented. 
The first involves the production of excited Kaluza Klein states 
within so-called Randall-Sundrum (RS) scenarios, the second is 
related to resonance production in TeV-1 sized extra dimensions 
and the third relates to phenomena from large extra dimensions (LED). 
Due to the close relation between the LED model and a so-called 
unparticle model, similar unparticle processes are also kept in this 
section.Randall-Sundrum Resonances, production processes
 
 
The graviton (G*) and gluon (KKgluon*) resonance states are assigned 
PDG code 5100039 and 5100021 respectively. The G* processes are 
described in [Bij01] and the KKgluon* process in [Ask11]. 
Decays into fermion and boson pairs are handled with the correct 
angular distributions, while subsequent decays are handled 
isotropically. 
 
 
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^* production. As usual, it would 
be double counting 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 isotropic. 
 
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. 
   
 
 
There is also one process for the production of a gluon resonance. 
 
flag   ExtraDimensionsG*:qqbar2KKgluon*   
 (default = off)
Scatterings q qbar → g^*/KKgluon^*. 
Code 5006. 
   
 
 
Randall-Sundrum Resonances, parameters
 
 
In the above scenario the main free parameters are the masses, which 
are set as usual. In addition there are the following coupling parameters. 
The coupling kappaMG follows the conventions in [Bij01], 
where as the flavour dependent couplings follow the conventions used in 
[Dav01]. 
 
flag   ExtraDimensionsG*:SMinBulk   
 (default = off)
Parameter to choose between the two scenarios: 
off, SM on the TeV brane (common kappaMG coupling); 
on, SM in the ED bulk (flavour dependent couplings). 
This parameter is only relevant for the lowest-order graviton 
(G*) processes, where as the first-order processes 
corresponds to the off scenario. 
   
 
flag   ExtraDimensionsG*:VLVL   
 (default = on)
Parameter to specify Z/W coupling scenario: 
off, usual Z/W boson couplings; 
on, coupling only to longitudinal Z/W bosons. 
In both cases the GZZ and GWW values are used 
and this parameter is only relevant when SMinBulk = on. 
The formulas for longitudinal bosons should be appropriate up to 
O(m_V/E_V) corrections. 
   
 
parm   ExtraDimensionsG*:kappaMG   
 (default = 0.054; minimum = 0.0)
dimensionless coupling, which enters quadratically in all on-shell 
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. 
In width and cross section calculations, kappa is fixed by 
the on-shell G^* mass and kappaMG, i.e. 
kappaMG scales with the off-shell G^* mass. 
   
 
parm   ExtraDimensionsG*:Gll   
 (default = 0.0; minimum = 0.0)
Coupling between graviton and leptons. 
   
 
parm   ExtraDimensionsG*:Gqq   
 (default = 0.0; minimum = 0.0)
Coupling between graviton and light quarks. 
   
 
parm   ExtraDimensionsG*:Gbb   
 (default = 0.0; minimum = 0.0)
Coupling between graviton and bottom quark. 
   
 
parm   ExtraDimensionsG*:Gtt   
 (default = 0.001; minimum = 0.0)
Coupling between graviton and top quark. 
   
 
parm   ExtraDimensionsG*:Ggg   
 (default = 0.000013; minimum = 0.0)
Coupling between graviton and gluon. 
   
 
parm   ExtraDimensionsG*:Ggmgm   
 (default = 0.000013; minimum = 0.0)
Coupling between graviton and gamma. 
   
 
parm   ExtraDimensionsG*:GZZ   
 (default = 0.001; minimum = 0.0)
Coupling between graviton and Z boson. 
   
 
parm   ExtraDimensionsG*:GWW   
 (default = 0.001; minimum = 0.0)
Coupling between graviton and W boson. 
   
 
parm   ExtraDimensionsG*:Ghh   
 (default = 0.001; minimum = 0.0)
Coupling between graviton and Higgs bosons. 
   
 
parm   ExtraDimensionsG*:KKgqR   
 (default = -0.2)
Coupling between KK-gluon and a right-handed light quark. 
   
 
parm   ExtraDimensionsG*:KKgqL   
 (default = -0.2)
Coupling between KK-gluon and a left-handed light quark. 
   
 
parm   ExtraDimensionsG*:KKgbR   
 (default = -0.2)
Coupling between KK-gluon and a right-handed bottom quark. 
   
 
parm   ExtraDimensionsG*:KKgbL   
 (default = 1.0)
Coupling between KK-gluon and a left-handed bottom quark. 
   
 
parm   ExtraDimensionsG*:KKgtR   
 (default = 4.0)
Coupling between KK-gluon and a right-handed top quark. 
   
 
parm   ExtraDimensionsG*:KKgtL   
 (default = 1.0)
Coupling between KK-gluon and a left-handed top quark. 
   
 
mode   ExtraDimensionsG*:KKintMode   
 (default = 0; minimum = 0; maximum = 2)
Choice of full g^*/KK-gluon^* structure or not in relevant 
processes. 
option  0 : full g^*/KK-gluon^* structure, with 
interference included.   
option  1 : only pure gluon_{SM} contribution.   
option  2 : only pure gluon_{KK} contribution.   
   
 
 
TeV^-1 Sized Extra Dimension, production processes
 
 
This section contains a processes involving the production 
of electroweak KK gauge bosons, i.e. gamma_{KK}/Z_{KK}, 
in one TeV^-1 sized extra dimension. The process is described 
in [Bel10] and allows for individual final states to be 
specified. 
 
flag   ExtraDimensionsTEV:ffbar2ddbar   
 (default = off)
Scatterings f fbar → (gamma_{KK}/Z_{KK}) → d dbar , 
Code 5061. 
   
 
flag   ExtraDimensionsTEV:ffbar2uubar   
 (default = off)
Scatterings f fbar → (gamma_{KK}/Z_{KK}) → u ubar , 
Code 5062. 
   
 
flag   ExtraDimensionsTEV:ffbar2ssbar   
 (default = off)
Scatterings f fbar → (gamma_{KK}/Z_{KK}) → s sbar , 
Code 5063. 
   
 
flag   ExtraDimensionsTEV:ffbar2ccbar   
 (default = off)
Scatterings f fbar → (gamma_{KK}/Z_{KK}) → c cbar , 
Code 5064. 
   
 
flag   ExtraDimensionsTEV:ffbar2bbbar   
 (default = off)
Scatterings f fbar → (gamma_{KK}/Z_{KK}) → b bbar , 
Code 5065. 
   
 
flag   ExtraDimensionsTEV:ffbar2ttbar   
 (default = off)
Scatterings f fbar → (gamma_{KK}/Z_{KK}) → t tbar , 
Code 5066. 
   
 
flag   ExtraDimensionsTEV:ffbar2e+e-   
 (default = off)
Scatterings f fbar → (gamma_{KK}/Z_{KK}) → e+ e- , 
Code 5071. 
   
 
flag   ExtraDimensionsTEV:ffbar2nuenuebar   
 (default = off)
Scatterings f fbar → (gamma_{KK}/Z_{KK}) → nue nuebar , 
Code 5072. 
   
 
flag   ExtraDimensionsTEV:ffbar2mu+mu-   
 (default = off)
Scatterings f fbar → (gamma_{KK}/Z_{KK}) → mu+ mu- , 
Code 5073. 
   
 
flag   ExtraDimensionsTEV:ffbar2numunumubar   
 (default = off)
Scatterings f fbar → (gamma_{KK}/Z_{KK}) → numu numubar , 
Code 5074. 
   
 
flag   ExtraDimensionsTEV:ffbar2tau+tau-   
 (default = off)
Scatterings f fbar → (gamma_{KK}/Z_{KK}) → tau+ tau- , 
Code 5075. 
   
 
flag   ExtraDimensionsTEV:ffbar2nutaunutaubar   
 (default = off)
Scatterings f fbar → (gamma_{KK}/Z_{KK}) → nutau nutaubar , 
Code 5076. 
   
 
 
TeV^-1 Sized Extra Dimension, parameters
 
 
Irrespective of the parameter options used, the particle produced, 
gamma_{KK}/Z_{KK}, will always be assigned code 5000023. 
 
mode   ExtraDimensionsTEV:gmZmode   
 (default = 3; minimum = 0; maximum = 5)
Choice of full gamma_{KK}/Z_{KK} structure or not in relevant 
processes. 
option  0 : full gamma_{SM}/Z_{SM} structure, with 
interference included.   
option  1 : only pure gamma_{SM} contribution.   
option  2 : only pure Z_{SM} contribution.   
option  3 : full gamma_{KK}/Z_{KK} structure, with 
interference included.   
option  4 : only pure gamma_{KK} contribution, with 
SM interference included.   
option  5 : only pure Z_{KK} contribution, with SM 
interference included.   
   
 
mode   ExtraDimensionsTEV:nMax   
 (default = 10; minimum = 1; maximum = 100)
The number of included KK excitations. 
   
 
parm   ExtraDimensionsTEV:mStar   
 (default = 4000.0; minimum = 1000.0)
The KK mass m^*, given by the inverse of the single extra 
dimension radius. 
   
 
 
Large Extra Dimensions, production processes
 
 
The LED graviton, where the KK-modes normally are summed and do not 
give rise to phenomena individually, is assigned PDG code 5000039. 
The graviton emission and virtual graviton exchange processes use 
the same implementation as the corresponding unparticle processes, 
which are all described in [Ask10]. It is also possible to 
generate monojet events from scalar graviton emission as described 
in [Azu05], by turning on the option GravScalar. 
 
 
Note: As discussed in [Ask09], for the graviton or 
unparticle emission processes the underlying Breit-Wigner mass 
distribution should be matched to the graviton mass spectrum in order 
to achieve an optimal MC efficiency. 
 
 
The following lowest order graviton emission processes are available. 
 
flag   ExtraDimensionsLED:monojet   
 (default = off)
Common switch for the group of lowest-order G jet emission 
processes, i.e. the three ones below. 
   
 
flag   ExtraDimensionsLED:gg2Gg   
 (default = off)
Scatterings g g → G g. 
Code 5021. 
   
 
flag   ExtraDimensionsLED:qg2Gq   
 (default = off)
Scatterings q g → G q. 
Code 5022. 
   
 
flag   ExtraDimensionsLED:qqbar2Gg   
 (default = off)
Scatterings q qbar → G g. 
Code 5023. 
   
 
flag   ExtraDimensionsLED:ffbar2GZ   
 (default = off)
Scatterings f fbar → G Z. 
Code 5024. 
   
 
flag   ExtraDimensionsLED:ffbar2Ggamma   
 (default = off)
Scatterings f fbar → G gamma. This process corresponds 
to the photon limit of the G Z process, as described in 
[Ask09]. 
Code 5025. 
   
 
 
The following LED processes with virtual graviton exchange are 
available. 
 
flag   ExtraDimensionsLED:ffbar2gammagamma   
 (default = off)
Scatterings f fbar → (LED G*) → gamma gamma. If the 
graviton contribution is zero, the results corresponds to the 
SM contribution, i.e. equivalent to 
PromptPhoton:ffbar2gammagamma. 
Code 5026. 
   
 
flag   ExtraDimensionsLED:gg2gammagamma   
 (default = off)
Scatterings g g → (LED G*) → gamma gamma. 
Code 5027. 
   
 
flag   ExtraDimensionsLED:ffbar2llbar   
 (default = off)
Scatterings f fbar → (LED G*) → l l , where 
l is a charged lepton. If the graviton contribution 
is zero, the results corresponds to the SM contribution, i.e. 
similar to WeakSingleBoson:ffbar2gmZ. Does not 
include t-channel amplitude relevant for e^+e^- to e^+e^- 
and no K-factor is used. 
Code 5028. 
   
 
flag   ExtraDimensionsLED:gg2llbar   
 (default = off)
Scatterings g g → (LED G*) → l l. 
Code 5029. 
   
 
 
Dijet production including graviton exchange is also available, using 
the same effective theory approach as the LED G exchange processes 
above or including more detailed amplitudes in accordance with 
[Fra11]. In case of the latter, the value of LambdaT 
is used as the value of the cut-off scale Lambda. For this 
reason the dijet processes only relates to the LED model and no 
unparticle versions are available. The processes are grouped together 
like their HardQCD equivalents and should therefore converge 
to the same results in the limit of an insignificant graviton 
contribution. 
 
 
Warning: These LED dijets processes are still being validated. 
 
flag   ExtraDimensionsLED:dijets   
 (default = off)
Common switch for the group of lowest-order jet jet 
production processes with graviton exchange, i.e. the six ones 
below. 
   
 
flag   ExtraDimensionsLED:gg2DJgg   
 (default = off)
Scatterings g g → (LED G*) → g g. 
Code 5030. 
   
 
flag   ExtraDimensionsLED:gg2DJqqbar   
 (default = off)
Scatterings g g → (LED G*) → q qbar. Number of 
outgoing flavours specified by nQuarkNew parameter 
below. 
Code 5031. 
   
 
flag   ExtraDimensionsLED:qg2DJqg   
 (default = off)
Scatterings q g → (LED G*) → q g and 
qbar g → (LED G*) → qbar g. 
Code 5032. 
   
 
flag   ExtraDimensionsLED:qq2DJqq   
 (default = off)
Scatterings q q(bar)' → (LED G*) → q q(bar)'. 
Including q and qbar of same or different 
flavours, but the outgoing flavours equals the incoming ones. 
Code 5033. 
   
 
flag   ExtraDimensionsLED:qqbar2DJgg   
 (default = off)
Scatterings q qbar → (LED G*) → g g. 
Code 5034. 
   
 
flag   ExtraDimensionsLED:qqbar2DJqqbarNew   
 (default = off)
Scatterings q qbar → (LED G*) → q' qbar'. Number of 
outgoing flavours specified by nQuarkNew parameter below. 
Code 5035. 
   
 
 
Large Extra Dimensions, parameters
 
 
flag   ExtraDimensionsLED:GravScalar   
 (default = off)
Allow the monojet processes to produce scalar graviton emission 
instead of the default tensor one. The scalar option is according 
to the processes described in [Azu05] and includes two 
coupling constants below. 
   
 
mode   ExtraDimensionsLED:n   
 (default = 2; minimum = 1)
Number of extra dimensions. 
   
 
parm   ExtraDimensionsLED:MD   
 (default = 2000.; minimum = 100.0)
Fundamental scale of gravity in D = 4 + n dimensions. 
   
 
parm   ExtraDimensionsLED:LambdaT   
 (default = 2000.; minimum = 100.0)
Ultraviolet cutoff parameter for the virtual graviton exchange processes. 
   
 
mode   ExtraDimensionsLED:NegInt   
 (default = 0; minimum = 0; maximum = 1)
Allows to change sign of the interference terms in the graviton exchange 
processes, common in connection to using the Hewett convention 
[Hew99]. 
option  0 : 1   
option  1 : -1   
   
 
mode   ExtraDimensionsLED:CutOffMode   
 (default = 0; minimum = 0; maximum = 3)
Options for when the hard scale of the process (e.g. sHat) 
approaches or exceed the scale of validity of the low energy effective 
theory (e.g. M_D). Note: Option 1 only concerns the 
graviton emission processes and the form factor is currently not available 
for the scalar graviton processes. 
option  0 : Do nothing, i.e. all values of sHat contribute. 
   
option  1 : Truncate contributing sHat region 
([Ask09]).   
option  2 : Form factor, using mu = renormScale2 .   
option  3 : Form factor, using mu = E_jet.   
   
 
parm   ExtraDimensionsLED:t   
 (default = 1.; minimum = 0.001)
Form factor parameter. 
   
 
parm   ExtraDimensionsLED:g   
 (default = 1.0; minimum = 0.0)
Coupling related to scalar graviton emission. 
   
 
parm   ExtraDimensionsLED:c   
 (default = 1.0; minimum = 0.0)
Coupling related to scalar graviton emission. 
   
 
mode   ExtraDimensionsLED:nQuarkNew   
 (default = 3; minimum = 0; maximum = 5)
Number of allowed outgoing new quark flavours in the above 
q qbar → (LED G*) → q' qbar' and 
g g → (LED G*) → q' qbar' 
processes. Similar to HardQCD:nQuarkNew for the QCD processes. 
   
 
mode   ExtraDimensionsLED:opMode   
 (default = 0; minimum = 0; maximum = 1)
Options to specify S function for LED dijet amplitudes. 
option  0 : Use detailed amplitude, as described in [Fra11]. 
   
option  1 : Use conventional LambdaT parametrization, 
like the other LED processes.   
   
 
 
Unparticles, production processes
 
 
As mentioned above, the similar unparticle and graviton processes 
share the same implementations. The unparticle processes, however, 
only use the dedicated unparticle parameters below. The unparticle 
is also assigned the PDG code 5000039 and is therefore called 
Graviton in the event record. The graviton and unparticle 
emission as well as virtual graviton and unparticle exchange processes 
are described in [Ask10]. 
 
 
Note: As discussed in [Ask09], for the graviton or 
unparticle emission processes the underlying Breit-Wigner mass 
distribution should be matched to the graviton mass spectrum in order 
to achieve an optimal MC efficiency. 
 
 
The following unparticle emission processes are available. 
 
flag   ExtraDimensionsUnpart:monojet   
 (default = off)
Common switch for the group of lowest-order U jet emission 
processes, i.e. the three ones below. 
   
 
flag   ExtraDimensionsUnpart:gg2Ug   
 (default = off)
Scatterings g g → U g. 
Code 5045. 
   
 
flag   ExtraDimensionsUnpart:qg2Uq   
 (default = off)
Scatterings q g → U q. 
Code 5046. 
   
 
flag   ExtraDimensionsUnpart:qqbar2Ug   
 (default = off)
Scatterings q qbar → U g. 
Code 5047. 
   
 
flag   ExtraDimensionsUnpart:ffbar2UZ   
 (default = off)
Scatterings f fbar → U Z. 
Code 5041. 
   
 
flag   ExtraDimensionsUnpart:ffbar2Ugamma   
 (default = off)
Scatterings f fbar → U gamma. This process corresponds 
to the photon limit of the U Z process, as described in 
[Ask09]. 
Code 5042. 
   
 
 
The following processes with virtual unparticle exchange are available. 
 
flag   ExtraDimensionsUnpart:ffbar2gammagamma   
 (default = off)
Scatterings f fbar → (U*) → gamma gamma. If the unparticle 
contribution is zero in the spin-2 case, the results corresponds to 
the SM contribution, i.e. equivalent to 
PromptPhoton:ffbar2gammagamma. 
Code 5043. 
   
 
flag   ExtraDimensionsUnpart:gg2gammagamma   
 (default = off)
Scatterings g g → (U*) → gamma gamma. 
Code 5044. 
   
 
flag   ExtraDimensionsUnpart:ffbar2llbar   
 (default = off)
Scatterings f fbar → (U*) → l lbar , where 
l is a charged lepton. If the unparticle contribution 
is zero, the results corresponds to the SM contribution, i.e. 
similar to WeakSingleBoson:ffbar2gmZ. Does not 
include t-channel amplitude relevant for e^+e^- to e^+e^- 
and no K-factor is used. 
Code 5048. 
   
 
flag   ExtraDimensionsUnpart:gg2llbar   
 (default = off)
Scatterings g g → (U*) → l lbar. 
Code 5049. 
   
 
 
Unparticles, parameters
 
 
mode   ExtraDimensionsUnpart:spinU   
 (default = 2; minimum = 0; maximum = 2)
Unparticle spin. 
   
 
parm   ExtraDimensionsUnpart:dU   
 (default = 1.4; minimum = 1.0)
Scale dimension parameter. 
   
 
parm   ExtraDimensionsUnpart:LambdaU   
 (default = 2000.; minimum = 100.0)
Unparticle renormalization scale. 
   
 
parm   ExtraDimensionsUnpart:lambda   
 (default = 1.0; minimum = 0.0)
Unparticle coupling to the SM fields. 
   
 
parm   ExtraDimensionsUnpart:ratio   
 (default = 1.0; minimum = 1.0; maximum = 1.0)
Ratio, lambda'/lambda, between the two possible coupling constants 
of the spin-2 ME. Warning: A ratio value different from one 
give rise to an IR divergence which makes the event generation very slow, so 
this values is fixed to ratio = 1 for the moment. 
   
 
mode   ExtraDimensionsUnpart:CutOffMode   
 (default = 0; minimum = 0; maximum = 1)
Options for when the hard scale of the process (e.g. sHat) 
approaches or exceed the scale of validity of the low energy effective 
theory (Lambda_U). This mode only concerns the unparticle 
emission processes. 
option  0 : Do nothing, i.e. all values of sHat 
contribute.   
option  1 : Truncate contributing sHat region 
([Ask09]).   
   
 
mode   ExtraDimensionsUnpart:gXX   
 (default = 0; minimum = 0; maximum = 2)
Chiral unparticle couplings, gXX = gLL = gRR. Only relevant 
for lepton production from spin-1 unparticle exchange. 
option  0 : 1   
option  1 : -1   
option  2 : 0   
   
 
mode   ExtraDimensionsUnpart:gXY   
 (default = 0; minimum = 0; maximum = 2)
Chiral unparticle couplings, gXY = gLR = gRL. Only relevant 
for lepton production from spin-1 unparticle exchange. 
option  0 : 1   
option  1 : -1   
option  2 : 0