Version 10 (modified by BenjF, 8 years ago) (diff) 

The most general Minimal Supersymmetric Standard Model
Author
 IPHC Strasbourg / University of Strasbourg
 fuks @ cern.ch
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 the most general one in a sense that it is keeping all the flavourviolating and helicitymixing terms in the Lagrangian and also all the possible additional CPviolating phases. This yields thus 105 new free parameters. In order to deal in a transparent way with all of those, our implementation will follow the commonly used universal set of conventions provided by the Supersymmetry Les Houches Accord, except for some minor points (see instructions below).
 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 & extensions
The MSSM implementation:
 Main FeynRules files (as a tarball): susy1.0.1.tgz (05.07.09).
 Example of parameter file: SPS 1a, with the corresponding restriction file.
 Parameter file translator, SLHA formatFeynRules format: Translator1.1.8.
 Example of a Mathematica® notebook loading the model and the parameters: SUSY.nb.
Not yet public / planned extensions (can be obtained on demand):
 Other gauges, such as Feynman gauge,
 Most general Rparity violating Minimal Supersymmetric Standard Model,
 Most general nexttoMinimal Supersymmetric Standard Model.
Instructions
The MSSM is implemented in unitary gauge.
 The switch FeynmanGauge (future devlopments) must thus be set to False,
 The flag $sWScale can be set to the value "weak" or "susy", depending on the scale to which the electroweak parameters have to be evaluated,
 The flag $svevScale can be set to the value "weak" or "susy", depending on the scale to which the vev has to be evaluated,
 The flag $CKMDiag can be set to the value True or False, allowing for a CKM matrix different from the identity or not (this can also be done through a possible restriction file),
 A parameter file must be loaded before running the model, or all the parameters would have a value of 1 (ReadLHAFile[Input>"myfile"]).
Interfaces
Here are the output files obtained for SPS1a after using the various translation interfaces and the example notebook given above.The prefix sps1a in the filename means the use of a sps1a restriction file to remove all the zero elements of the mixing matrices from the vertices.
 TeX: tex.tgz (13.06.09).
 FeynArts: SUSY.mod (12.06.09).
 MadGraph: mg.tgz (12.06.09), sps1a.mg.tgz (05.07.09).
 CalcHEP: ch.tgz (12.06.09), sps1a.ch.tgz (08.07.09).
 SHERPA: not available yet.
Validation
In order to validate our implementation, we have performed the following tests.
 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 , private communication.
 Comparison of the builtin CalcHEP (CHST) and MadGraph (MGST) model files with the FeynRules generated ones, MGFR and CHFR, 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.
 1 to 2 decay widths for all Standard Model particles and their superpartners (320 channels), for MGFR and MGST: decay.tgz.
 2 to 2 cross sections related to the production of any pair of particles from a Standard Model initial state of 2x600 GeV and 2x1000 GeV, and for the four implementations CHST, CHFR, MGST and MGFR. CalcHEP is run in unitary gauge.
 Leptonic initial states (twice 149 channels): lepttgz.
 Quark initial state (twice 181 channels): quark.tgz.
 Gauge boson initial states (twice 291 channels): vv.tgz.
 Other (twice 15 channels): other.tgz.
 2 → 3 matrix element evaluation for given phase space points: not available yet.
 Note: we have some disagreements (red spots in the jpgfiles). They are due to
 A certain amount of bugs in the CHST implementation.
 Massless propagators in tchannel diagrams leading to unreliable results for all implementations. We have tested here unintegrated matrix elements for 100 different phase space points: sa.tgz.
Attachments (15)

susy1.0.1.tgz
(12.8 KB) 
added by BenjF 8 years ago.
FeynRules MSSM model files

SUSY.nb
(9.1 KB) 
added by BenjF 8 years ago.
Example notebook

FRT_paramcard.dat
(18.8 KB) 
added by BenjF 8 years ago.
SPS1a paramcard

sps1a_mg.tgz
(61.3 KB) 
added by BenjF 7 years ago.
MadGraph model files for sps1a

validation.tgz
(1.9 MB) 
added by BenjF 7 years ago.
Validation tables for sps1a

sps1a_tex.tgz
(11.5 KB) 
added by BenjF 7 years ago.
Output of the TeX interface

sps1a_fa.tgz
(23.7 KB) 
added by BenjF 7 years ago.
FeynArts model files for sps1a

sps1a_wo.dat
(20.8 KB) 
added by BenjF 7 years ago.
ParamCard for MSSMSF compatible with Whizard

MSSM.nb
(13.0 KB) 
added by BenjF 7 years ago.
Example notebook

sps1a_wo.tgz
(236.3 KB) 
added by BenjF 7 years ago.
Whizard model files for sps1a

sps1a.dat
(20.8 KB) 
added by BenjF 7 years ago.
Param_card for the sps1a point

mssm.fr
(45.5 KB) 
added by BenjF 6 years ago.
MSSM model file v 1.3.13

sps1a_ufo.tgz
(61.1 KB) 
added by BenjF 5 years ago.
UFO files for the MSSM

sps1a_ch.tgz
(51.6 KB) 
added by BenjF 5 years ago.
CalcHep model files for sps1a
 translator2.2.tgz (33.5 KB)  added by BenjF 4 years ago.