Abstract : A search for the decays B+c→J/ψD(∗)0K+ and B+c→J/ψD(∗)+K∗0 is performed with data collected at the LHCb experiment corresponding to an integrated luminosity of 3 fb−1. The decays B+c→J/ψD0K+ and B+c→J/ψD∗0K+ are observed for the first time, while first evidence is reported for the B+c→J/ψD∗+K∗0 and B+c→J/ψD+K∗0 decays. The branching fractions of these decays are determined relative to the B+c→J/ψπ+ decay. The B+c mass is measured, using the J/ψD0K+ final state, to be 6274.28±1.40(stat)±0.32(syst) MeV/c2. This is the most precise single measurement of the B+c mass to date.
R. Aaij, L. Beaucourt, M. Chefdeville, D. Decamp, N. Déléage, et al.. Observation of B+c→J/ψD(∗)K(∗) decays. Physical Review D, American Physical Society, 2017, 95, pp.032005 ⟨10.1103/PhysRevD.95.032005⟩. ⟨in2p3-01431311⟩