Last modified 6 years ago Last modified on 04/11/11 18:53:43

The Next-To-Minimal Supersymmetric Standard Model


Benjamin Fuks

  • IPHC Strasbourg / University of Strasbourg
  • fuks@…

Description of the model & references

Our NMSSM implementation in FeynRules is general in the sense that it is keeping all the flavour-violating and helicity-mixing terms in the Lagrangian and also all the possible additional CP-violating phases. In order to deal in a transparent way with the more than 100 parameters, our implementation follows the commonly used universal set of conventions provided by the Supersymmetry Les Houches Accord.

Model files

  • MSSM implementation using the superspace module (compatible with FeynRules 1.6.x)
  • p1.dat: parameter file to be read, associated to the p1 scenario described in JHEP 0807 (2008) 002. In the case of the Whizard interface, this parameter file must be used instead.
  • NMSSM.nb: Example of a Mathematica® notebook loading the model and the parameters.

Specific instructions

  • Both Feynman and unitarity gauges are supported.
  • 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

p1_ch.tgzThe model files for CalcHep.
p1_fa.tgzThe model files for FeynArts.
p1_mg.tgzThe model files for MadGraph 4.
p1_ufo.tgzThe model files in UFO format (e.g. for MadGraph 5).
p1_wo.tgzThe model files for Whizard.
p1_tex.tgzLaTeX output.

The Sherpa interface is not supported.


  • The present NMSSM model has been validated against the first NMSSM implementation in FeynRules, using component fields. 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 NMSSM implementation has been validated as follow. We have compared of the built-in !Whizard model files with the FeynRules generated ones (CalcHep and MadGraph) through the calculation of various 2 to 2 cross sections. For each implementation, we have fixed all the parameters to those of a specific benchmark point 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 2x1500 GeV, in unitarity gauge. The results are available here validation.tgz.