Observation of the ${\Xi }_b^{-}\to {\Xi }^{-}{\mu }^{+}{\mu }^{-}$ and study of the ${\Xi }_b^{-}\to {\Xi }^{-}\psi (2S)$ decays

LHCb collaboration, R. Aaij, M. Abdelfatah +1161

The rare decay ${\Xi }_b^{-}\to {\Xi }^{-}{\mu }^{+}{\mu }^{-}$ is observed for the first time using proton-proton collision data collected by the LHCb experiment at centre-of-mass energies of $7$, $8$ and~$…