Search for the rare decays Bs -->mumu and Bd -->mumu

TL;DR

This paper reports a search for rare Bs and Bd meson decays into muon pairs using LHCb data, setting upper limits on their branching ratios consistent with background expectations.

Contribution

First search for Bs and Bd to mu mu decays at 7 TeV with LHCb, establishing new upper limits on their branching ratios.

Findings

No significant excess observed over background

Upper limit on BR(Bs-->mumu) < 5.6 x 10^{-8}

Upper limit on BR(Bd-->mumu) < 1.5 x 10^{-8}

Abstract

A search for the decays Bs-->mumu and Bd-->mumu is performed with about 37 pb^{-1} of pp collisions at sqrt{s} = 7 TeV collected by the LHCb experiment at the Large Hadron Collider at CERN. The observed numbers of events are consistent with the background expectations. The resulting upper limits on the branching ratios are BR(Bs-->mumu) < 5.6 x 10^{-8} and BR(Bd-->mumu) <1.5 x 10^{-8} at 95% confidence level.