# Software

## SusyKit

SusyKit is a software package designed to determine the posterior probability distributions of the parameters and derived quantities in models of supergravity grand uniﬁcation. It uses the MultiNest package which eﬃciently samples the parametric space using Bayesian inference. The likelihood function for parameter points is determined by a simple conﬁguration ﬁle.

The physical quantities used to construct the likelihood function are computed using the standard codes. The renormalization group equations evolve the soft supersymmetry-breaking couplings from the high (grand uniﬁcation) scale to the electroweak scale where physical masses are computed using SOFTSUSY. The Higgs masses are then corrected using all relevant 2-loop diagrams by FeynHiggs. The thermal relic density of cold LSP dark matter $\Omega_{\widetilde\chi}h^2$ using either micrOMEGAs or SuperISO Relic. Various ﬂavor and precision electroweak observables such $\sin^2\theta_\mathrm{W}^\mathrm{eff}$, $\mathcal{B}r(B^0_s\to\mu^+\mu^-)$, $\delta a_\mu^\mathrm{SUSY}$, etc. may be computed with FeynHiggs, micrOMEGAs, or SuperISO Relic.

After the Monte Carlo sampling, the sample points are binned to construct the posterior probability distributions in the desired parameters and derived quantities using simple Python scripts.