A Flavor Kit for BSM models

Abstract

We present a new kit for the study of flavor observables in models beyond the standard model. The setup is based on the public codes SARAH and SPheno and allows for an easy implementation of new observables. The Wilson coefficients of the corresponding operators in the effective Lagrangian are computed by SPheno modules written by SARAH. New operators can also be added by the user in a modular way. For this purpose a handy Mathematica package called PreSARAH has been developed. This uses FeynArts and FormCalc to derive the generic form factors at tree- and 1-loop levels and to generate the necessary input files for SARAH. This framework has been used to implement BR($\ell_α\to \ell_βγ$), BR($\ell_α\to 3\, \ell_β$), CR($μ-e,A$), BR($τ\to P \, \ell$), BR($h\to \ell_α\ell_β$), BR($Z\to \ell_α\ell_β$), BR($B_{s,d}^0 \to \ell \bar{\ell}$), BR($\bar B \to X_sγ$), BR($\bar B \to X_s \ell \bar{\ell}$), BR($\bar B \to X_{d,s} ν\bar ν$), BR($K^+ \to π^+ ν\bar ν$), BR($K_L \to π^0 ν\bar ν$), $ΔM_{B_s,B_d}$, $ΔM_K$, $\varepsilon_K$, BR($B \to K μ\barμ$), BR($B\to \ell ν$), BR($D_s \to \ell ν$) and BR($K \to \ell ν$) in SARAH. Predictions for these observables can now be obtained in a wide range of SUSY and non-SUSY models. Finally, the user can use the same approach to easily compute additional observables.

68 pages; PreSARAH and FlavorKit (included in SARAH 4.2.0) can be downloaded at http://sarah.hepforge.org/FlavorKit.html; v2: minor extensions, matches published version; v3: unifying layout in the appendix