First observation of the decay $B^{+}\to {\pi }^{+}{\mu }^{+}{\mu }^{-}$

LHCb Collaboration, R. Aaij, C. Abellan Beteta +621

A discovery of the rare decay $B^{+}\to {\pi }^{+}{\mu }^{+}{\mu }^{-}$ is presented. This decay is observed for the first time, with 5.2 $\sigma$ significance. The observation is made usin…