SloopS

is a code for the calculation of cross sections and other observables at one-loop in the MSSM. Renormalisation is performed in the On-Shell Scheme with the possibility of easily switching to other schemes. SloopS has been designed so that it has applications not only for physics at colliders but also for astrophysics and cosmology. 

The principle  behind the code is modularity. Considering the complex structure of the MSSM (large number of parameters) and that no  simple complete renormalisation scheme of the MSSM has emerged one should have a code that is flexible enough so that it simple to define the model file. Moreover since different codes exist already that deal with important ingredients in the calculation of  loops it is best  to exploit these, combine them together and whenever improve on them.

The model file is implemented in automatic way both at tree-level and at the one-loop level with the help of LANHEP  adapted such that it can be interfaced with  the FeynCalc/FormCalc package. LANHEP has been extended so that it can generate counterterms in a most efficient manner.

• Model file:

• example of particle definition, gauge fixing and ghost Lagrangian via BRS in LANHEP.
• Feynman rules including counterterms (see here).
• renormalisation conditions (see here).

• A poweful feature of the code is the use of a non-linear gauge fixing condition (see here) .

• The aim of the code is also to be used for annihilation of dark matter that is highly non relativistic, this calls for an added routine in the loop tensor reduction that avoids Gram determinants. Our trick is to do this and this.
  • Overview of strategy (here)
  • Example of combining SloopS with micrOMEGAs to predict the photon flux from neutralino annihilation.