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

We perform a study of the Standard Model (SM) fit to the mixing quantities $\mathrm{\Delta }{M}_{B_s}$, and $\mathrm{\Delta }{\mathrm{\Gamma }}_{B_s}\mathrm{/}\mathrm{\Delta }{M}_{B_s}$ 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.