Rare $B_s$ decays to $\eta$ and ${\eta }^{\prime }$ final states

Abstract

We study exclusive $B_s$ decays to final states with $\eta$ and ${\eta }^{\prime }$, induced by the rare $b\to s{\ell }^{+}{\ell }^{-}$ and $b\to s\nu \bar{\nu }$ transitions. Differential decay rates and total branching fractions are predicted in the Standard Model, adopting the flavour scheme for the description of the $\eta$-${\eta }^{\prime }$ mixing. We discuss the theoretical uncertainty related to the hadronic matrix elements. We also consider these decay modes in a new Physics scenario with a single universal extra dimension, studying the dependence of branching ratios and decay distributions on the compactification scale $R^{-1}$ of the extra dimension.

Comments: RevTeX, 10 pages, 4 figures