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

TL;DR

This paper analyzes how new physics could influence B_s meson mixing and decay to mu+mu-, using Standard Model fits to constrain possible new physics contributions and their effects on branching ratios.

Contribution

It provides a combined analysis linking B_s mixing parameters with the branching ratio of B_s -> mu+mu- within various new physics models, setting bounds on NP amplitudes.

Findings

NP contributions to B_s -> mu+mu- are generally constrained below the SM level.

Standard Model fits effectively limit the size of possible NP effects.

Most NP scenarios predict smaller branching fractions than the SM expectation.

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.