Rare leptonic decays of B(s)0​ mesons are sensitive probes of New
Physics effects. A combination of the CMS and LHCb analyses on the search of
the rare decays Bs0​→μ+μ− and B0→μ+μ− is presented. The branching fractions of Bs0​→μ+μ− and B0→μ+μ− are measured to be
\mathcal{B}(B_{s}^0 \rightarrow \mu^+\mu^-) = (2.8 \,^{+0.7}_{-0.6}) \times
10^{-9} and \mathcal{B}(B^0 \rightarrow \mu^+\mu^-) = (3.9 \,^{+1.6}_{-1.4})
\times 10^{-10} respectively. A statistical significances of 6.2σ is
evaluated for Bs0​→μ+μ− from the Wilks' theorem while a
significance of 3.0σ is measured for B0→μ+μ−
from the Feldman-Cousins procedure.Comment: Proceedings of the 8th International Workshop on the CKM Unitarity
Triangle (CKM 2014), Vienna, Austria, September 8-12, 201