Observation of Bc+→J /ψ D(*)K(*) decays

Abstract

A search for the decays Bc+→J /ψ D(*)0K+ and Bc+→J /ψ D(*)+K*0 is performed with data collected at the LHCb experiment corresponding to an integrated luminosity of 3 fb-1 . The decays Bc+→J /ψ D0K+ and Bc+→J /ψ D*0K+ are observed for the first time, while first evidence is reported for the Bc+→J /ψ D*+K*0 and Bc+→J /ψ D+K*0 decays. The branching fractions of these decays are determined relative to the Bc+→J /ψ π+ decay. The Bc+ mass is measured, using the J /ψ D0K+ final state, to be 6274.28 ±1.40 (stat) ±0.32 (syst) MeV /c2 . This is the most precise single measurement of the Bc+ mass to date.