Abstract: Signals consistent with the B+c(2S) and B*+c(2S) states are observed in proton-proton collisions at ?s=13??TeV, in an event sample corresponding to an integrated luminosity of 143??fb?1, collected by the CMS experiment during the 2015?2018 LHC running periods. These excited ¯bc states are observed in the B+c?+?? invariant mass spectrum, with the ground state B+c reconstructed through its decay to J/??+. The two states are reconstructed as two well-resolved peaks, separated in mass by 29.1±1.5(stat)±0.7(syst)??MeV. The observation of two peaks, rather than one, is established with a significance exceeding five standard deviations. The mass of the B+c(2S) meson is measured to be 6871.0±1.2(stat)±0.8(syst)±0.8(B+c)??MeV, where the last term corresponds to the uncertainty in the world-average B+c mass.
