Evidence for the decay $B_{s}^0 \rightarrow \overline{K}{}^{*0}\mu^+\mu^-$

TL;DR

This paper reports evidence for the rare decay $B_{s}^0 ightarrow ar{K}^{*0}\mu^+\mu^-$, with a significance of 3.4 sigma, using LHCb data from multiple collision energies, and measures its branching fraction.

Contribution

First evidence for the decay $B_{s}^0 ightarrow ar{K}^{*0}\mu^+\mu^-$ with a quantified branching fraction from LHCb data at different energies.

Findings

Evidence with 3.4 sigma significance

Branching fraction measured as approximately 2.9 x 10^{-8}

Data collected at 7, 8, and 13 TeV energies

Abstract

A search for the decay $B_{s}^0 \rightarrow \overline{K}{}^{*0}\mu^+\mu^-$ is presented using data sets corresponding to 1.0, 2.0 and 1.6 $\text{fb}^{-1}$ of integrated luminosity collected during $pp$ collisions with the LHCb experiment at centre-of-mass energies of 7, 8 and 13 TeV, respectively. An excess is found over the background-only hypothesis with a significance of 3.4 standard deviations. The branching fraction of the $B_{s}^0 \rightarrow \overline{K}{}^{*0}\mu^+\mu^-$ decay is determined to be $\mathcal{B}(B_{s}^0 \rightarrow \overline{K}{}^{*0}\mu^+\mu^-) = [2.9 \pm 1.0~(\text{stat}) \pm 0.2~(\text{syst}) \pm 0.3~(\text{norm})] \times 10^{-8}$, where the first and second uncertainties are statistical and systematic, respectively. The third uncertainty is due to limited knowledge of external parameters used to normalise the branching fraction measurement.