Observation of muonic Dalitz decays of ${\chi }_b$ mesons and precise spectroscopy of hidden-beauty states

LHCb collaboration, R. Aaij, A. S. W. Abdelmotteleb +1117

The decays of the ${\chi }_{b1}(1P)$, ${\chi }_{b2}(1P)$, ${\chi }_{b1}(2P)$ and ${\chi }_{b2}(2P)$ mesons into the ${\rm Y}(1S){\mu }^{+}{\mu }^{-}$ final state are observed with a high significance using proton-proton coll…