Version 27 (modified by BenjF, 9 years ago) (diff) 

The Minimal Supersymmetric Standard Model
Author
 IPHC Strasbourg / University of Strasbourg
 fuks@…
Description of the model & references
One popular Beyond the Standard Model theory is the Minimal Supersymmetric Standard Model (MSSM). Its main features are to link bosons with fermions and unify internal and external symmetries. Moreover, it allows for a stabilization of the gap between the Planck and the electroweak scale and for gauge coupling unification at high energies, provides a dark matter candidate as the lightest supersymmetric particle and appears naturally in string theories. However, since supersymmetric particles have not yet been discovered, supersymmetry must be broken at low energies, which makes the superpartners massive in comparison to their Standard Model counterparts.
Our MSSM implementation in FeynRules is general in the sense that it is keeping all the flavourviolating and helicitymixing terms in the Lagrangian and also all the possible additional CPviolating phases. In order to deal in a transparent way with all the free parameters of the model, our implementation follows the commonly used universal set of conventions provided by the Supersymmetry Les Houches Accord.
The current version of the model, compatible with FeynRules v1.6.0 and below used the superspace module of FeynRules.
 Phys.Rept.110 (1984) 1: H. P. Nilles, Supersymmetry, Supergravity and Particle Physics.
 Phys.Rept.117 (1985) 75: H. E. Haber and G. L. Kane, The Search for Supersymmetry: Probing Physics Beyond the Standard Model.
 Phys.Rev.D41 (1990) 3464: J. Rosiek, Complete Set of Feynman Rules for the Minimal Supersymmetric Extension of the Standard Model.
 hepph/9709356: S. P. Martin, A Supersymmetry primer.
 JHEP 0407 (2004) 36: P. Skands et al, SUSY Les Houches accord: Interfacing SUSY spectrum calculators, decay packages, and event generators .
 Comput.Phys.Commun.180 (2009) 8: B. C. Allanach et al, SUSY Les Houches Accord 2.
Model files
 mssm.fr: MSSM implementation using the superspace module (compatible with FeynRules 1.6.x)
 sps1a: parameter file to be read, associated to the sps1a scenario. In the case of the Whizard interface, this parameter file must be used instead.
 MSSM.nb: Example of a Mathematica® notebook loading the model and the parameters.
 susy1.0.1.tgz (05.07.09): Old MSSM implementation (compatible with FeynRules 1.4.x), with the corresponding parameter file for the sps1a benchmark point, and the old example notebook.
Specific instructions
 The switch FeynmanGauge allows to choose between Feynman and unitarity gauge.
 The flags $CKMDiag and $MNSDiag, being set to True or False, allow for CKM and PMNS matrices different from the identity or not.
 A parameter file must be loaded before running the model, or all the parameters would have a value of 1 (ReadLHAFile[Input>"myfile"]).
Optimized matrix element generator models for sps1a (removal of all zero terms in the vertices) and TeX interface output
sps1a_ch.tgz  The model files for CalcHep. 
sps1a_fa.tgz  The model files for FeynArts. 
sps1a_mg.tgz  The model files for MadGraph 4. 
sps1a_ufo.tgz  The model files in UFO format (e.g. for MadGraph 5). 
sps1a_wo.tgz  The model files for Whizard. 
sps1a_tex.tgz  LaTeX output. 
The Sherpa interface is not supported.
Validation
 The MSSMsuperspace model has been validated against the first MSSM implementation in FeynRules. We calculate the Feynman rules associated to the difference of the old and the new Lagrangian, and obtains an empty set of rules.
 The old MSSM implementation has been validated as follow:
 FeynArts model file generated by FeynRules: recalculation of the helicity amplitudes related to the hadroproduction of a pair of supersymmetric particles and comparison with the three references:
 Nucl. Phys. B787 (2007) 1: G. Bozzi, B. Fuks, B. Herrmann and M. Klasen, Squark and gaugino hadroproduction and decays in nonminimal flavour violating supersymmetry.
 Nucl. Phys. B810 (2009) 266: B. Fuks, B. Herrmann and M. Klasen, Flavour Violation in GaugeMediated Supersymmetry Breaking Models: Experimental Constraints and Phenomenology at the LHC.
 B. Fuks, B. Herrmann and M. Klasen, in preperation.
 Comparison of the builtin Monte Carlo model files with the FeynRules generated ones (CalcHep, MadGraph, !Whizard and !Sherpa) through the calculation of various quantities. For each implementation, we have fixed all the parameters to those of SPS 1a and set the widths of the particles to zero. We have calculated 2 to 2 cross sections related to the production of any pair of particles from a Standard Model initial state of 2x600 GeV, in unitarity gauge.The results are available here validation.tgz. We have some disagreements (red spots in the jpgfiles). They are due to
 A certain amount of bugs in the CHST implementation.
 Incompatibilities within the Sherpa interface.
 Massless propagators in tchannel diagrams leading to unreliable results for all implementations.
 FeynArts model file generated by FeynRules: recalculation of the helicity amplitudes related to the hadroproduction of a pair of supersymmetric particles and comparison with the three references:
Attachments (15)

susy1.0.1.tgz
(12.8 KB) 
added by BenjF 10 years ago.
FeynRules MSSM model files

SUSY.nb
(9.1 KB) 
added by BenjF 10 years ago.
Example notebook

FRT_paramcard.dat
(18.8 KB) 
added by BenjF 10 years ago.
SPS1a paramcard

sps1a_mg.tgz
(61.3 KB) 
added by BenjF 9 years ago.
MadGraph model files for sps1a

validation.tgz
(1.9 MB) 
added by BenjF 9 years ago.
Validation tables for sps1a

sps1a_tex.tgz
(11.5 KB) 
added by BenjF 9 years ago.
Output of the TeX interface

sps1a_fa.tgz
(23.7 KB) 
added by BenjF 9 years ago.
FeynArts model files for sps1a

sps1a_wo.dat
(20.8 KB) 
added by BenjF 9 years ago.
ParamCard for MSSMSF compatible with Whizard

MSSM.nb
(13.0 KB) 
added by BenjF 9 years ago.
Example notebook

sps1a_wo.tgz
(236.3 KB) 
added by BenjF 9 years ago.
Whizard model files for sps1a

sps1a.dat
(20.8 KB) 
added by BenjF 9 years ago.
Param_card for the sps1a point

mssm.fr
(45.5 KB) 
added by BenjF 8 years ago.
MSSM model file v 1.3.13

sps1a_ufo.tgz
(61.1 KB) 
added by BenjF 7 years ago.
UFO files for the MSSM

sps1a_ch.tgz
(51.6 KB) 
added by BenjF 7 years ago.
CalcHep model files for sps1a
 translator2.2.tgz (33.5 KB)  added by BenjF 6 years ago.