Combination of the ATLAS, CMS and LHCb results on the $B^0_{(s)}\to\mu^+\mu^-$ decays.

A combination of results on the rare $B^0_s\to\mu^+\mu^-$ and $B^0\to\mu^+\mu^-$ decays from the ATLAS, CMS, and LHCb experiments using data collected at the Large Hadron Collider between 2011 and 2016, is presented. The $B^0_s\to\mu^+\mu^-$ branching fraction is obtained to be $2.69^{+0.37}_{-0.35}\times 10^{-9}$ and ithe effective lifetime of the $B^0_s\to\mu^+\mu^-$ decay is measured to be $\tau_{B^0_s\to\mu^+\mu^-} = 1.91^{+0.37}_{-0.35}$ ps. An upper limit on the $B^0\to\mu^+\mu^-$ branching fraction is evaluated to be $\cal{B}(B^0\to\mu^+\mu^-) < 1.6 (1.9)$ at 90\% (95\%) confidence level. An upper limit on the ratio of the $B^0\to\mu^+\mu^-$ and $B^0_s\to\mu^+\mu^-$ branching fractions is obtained to be $0.052$ ($0.060$) at 90\% (95\%) confidence level.