Search for Bs -> mu mu and B0 -> mu mu decays in CMS

TL;DR

This paper reports a search for rare B meson decays into muon pairs using CMS data at 7 TeV, setting upper limits on their branching fractions and combining results with LHCb.

Contribution

It provides the first upper limits on B0 and Bs decays into muons at 7 TeV and combines CMS and LHCb results for improved constraints.

Findings

No significant excess observed over background.

Upper limits on branching fractions are set: BF(Bs -> mu mu) < 1.9e-8.

Combined limit with LHCb is BF < 1.1e-8.

Abstract

A search for the rare decays (Bs -> \mu \mu) and (B0 -> \mu\mu) performed in pp collisions at sqrt{s} = 7 TeV is presented. The data sample, collected by the CMS experiment at the LHC, corresponds to an integrated luminosity of 1.14 /fb. In both cases the number of events observed after all selection requirements is consistent with expectations from background and standard model signal predictions. The resulting upper limits on the branching fractions are BF(Bs -> \mu\mu) < 1.9 * 10^{-8} and BF(B0 -> \mu \mu) < 4.6 * 10^{-9} at 95% confidence level (CL). Furthermore, the combination of the results of the search for the decay (Bs -> \mu \mu) by the CMS and LHCb experiments is presented. The combined upper limit is BF < 1.1 * 10^{-8} at 95% CL.