Observation of the J/$\psi$ $\to$ ${\mu }^{+}{\mu }^{-}{\mu }^{+}{\mu }^{-}$ decay in proton-proton collisions at $\sqrt{s}$ = 13 TeV

CMS Collaboration

The J/$\psi$ $\to$ ${\mu }^{+}{\mu }^{-}{\mu }^{+}{\mu }^{-}$ decay has been observed with a statistical significance in excess of five standard deviations. The analysis is based on an event sample of proton-pro…