Observation of the decay $ B_c^{+} $ → J/ψ K + K − π +

Abstract

A bstract The decay $ B_c^{+} $ → J/ψK + K − π + is observed for the first time, using protonproton collisions collected with the LHCb detector corresponding to an integrated luminosity of 3 fb −1 . A signal yield of 78 ± 14 decays is reported with a significance of 6.2 standard deviations. The ratio of the branching fraction of $ B_c^{+} $ → J/ψK + K − π + decays to that of $ B_c^{+} $ → J/ψπ + decays is measured to be 0 . 53 ± 0 . 10 ± 0 . 05, where the first uncertainty is statistical and the second is systematic.