Search for the rare decays $B_s^0\to {\mu }^{+}{\mu }^{-}$ and $B^0\to {\mu }^{+}{\mu }^{-}$

Abstract

A search for the decays $B_s^0\to {\mu }^{+}{\mu }^{-}$ and $B^0\to {\mu }^{+}{\mu }^{-}$ is performed with 0.37 fb⁻¹ of pp collisions at $\sqrt{s}=7\text{TeV}$ collected by the LHCb experiment in 2011. The upper limits on the branching fractions are $\mathcal{B}(B_s^0\to {\mu }^{+}{\mu }^{-})<1.6\times {10}^{-8}$ and $\mathcal{B}(B^0\to {\mu }^{+}{\mu }^{-})<3.6\times {10}^{-9}$ at 95% confidence level. A combination of these results with the LHCb limits obtained with the 2010 dataset leads to $\mathcal{B}(B_s^0\to {\mu }^{+}{\mu }^{-})<1.4\times {10}^{-8}$ and $\mathcal{B}(B^0\to {\mu }^{+}{\mu }^{-})<3.2\times {10}^{-9}$ at 95% confidence level.