Relating B_s Mixing and B_s -> mu+mu- with New Physics

Abstract

We perform a study of the Standard Model (SM) fit to the mixing quantities $\Delta M_{B_s}$, and $\Delta {\Gamma }_{B_s}/\Delta M_{B_s}$ in order to bound contributions of New Physics to $B_s$ mixing. We then use this to explore the branching fraction of $B_s\to {\mu }^{+}{\mu }^{-}$ in certain models of New Physics (NP). In most cases, this constrains NP amplitudes for $B_s\to {\mu }^{+}{\mu }^{-}$ to lie below the SM component.

Comments: 27 pages, 5 figures; corrected misprints, updated numerical inputs and new references