MSSM (and extensions) Lagrangian for CompHEP package


We present here the files necessary for SUSY processes calculation by CompHEP package. The installation instructions are in the README file . Start CompHEP and new models will appear in menu. CompHEP/SUSY models were created my means of LanHEP package. Last versions of LanHEP (2.4, 2.5) include input files to generate MSSM and some extensions.


The LanHEP input files to generate MSSM and its extensions come within LanHEP distributions. One can use ready models listed below: Basic MSSM contains the models number 5 and 6 (unitary and Feynman gauge fixing), extensions are numbers 7-8. If you install several extensions, you should unpack the archive in a temporary directory and rename the files to the next free number (e.g. vars8.mdl -> vars9.mdl, func8.mdl -> func9.mdl, etc). Then copy renamed files to the 'models' subdirectory of the CompHEP user directory.

SUSY Les Houches Accord (SLHA) interface

To use SLHA in CompHEP/SUSY, one has to update usrlib.a (or libmssm.a in newer CompHEP versions). Compile new sugrac.c file and put it into the library (ar -r usrlib.a sugrac.o). Files sugraf.f and sugrag.f are not necessary in this library. Now CompHEP will write the file named slhaInput with RGE input parameters (M0, M1/2, tb, etc) in SLHA format, then it executes the script named slhaScript, and finally reads soft masses and trilinear couplings from the file named slhaOutput, produced by script. The script is searched first in the current directory (usually results/) and then in the parent directory (usally where symbolic part of CompHEP is launched). Generally slhaScript may be a compiled executable file rather than script. There are examples of scripts for some packages (you should download necessary package independently, and edit the script to set the directory where the package is): Rename the required file to slhaScript, do not forget to set execution permission (chmod +x).


NMSSM for CompHEP can be downloaded here . File nmssm2.c in the archive should be added to library usrlib.a (libmssmlib.a in newer CompHEP versions). You should download the NMHDECAY package and create SLHA (it is default currently) executable, name it nmhdecay and place it to the directory where numerical CompHEP is launched (usually results/ ). Remember that NMHDECAY also require the directory LEPCON to be nearby.
New parameters in the model are hL for lambda and hK for kappa, hLs and hKs are corresponding soft parameters. Notation for third fermion and sfermion parameters is slightly changed: everywhere top->t, bot->b, tau->l. See further details in the paper on NMSSM in micrOMEGAs (to appear in hep-ph in May 2005). The present model has mixing of d,s quarks by Cabbibo angle while the model in micrOMEGAs has diagonal CKM.

Updates history

Old versions (as of June 2000)

Last update: March 31, 2008 , tel&fax (095)9390397