Observation of the B0 → (D)over-bar*0K+ π- and Bs0 → (D)over-bar*0K-π+ decays

The first observations of B0 → anti-D*(2007)0 K+ π− and B0s → anti-D*(2007)0 K− π+ decays are presented, and their branching fractions relative to that of the B0 → anti-D*(2007)0 π+ π− decay are reported. These modes can potentially be used to investigate the spectroscopy of charm and charm-strange resonances and to determine the angle γ of the Cabibbo-Kobayashi-Maskawa unitarity triangle. It is also important to understand them as a source of potential background in determinations of γ from B+ → D K+ and B0 → D K+ π− decays. The analysis is based on a sample corresponding to an integrated luminosity of 5.4 fb^−1 of proton-proton collision data at 13 TeV center-of-mass energy recorded with the LHCb detector. The anti-D*(2007)0 mesons are fully reconstructed in the anti-D0 π0 and anti-D0 γ channels with the anti-D0 → K+ π− decay. A novel weighting method is used to subtract background while simultaneously applying an event-by-event efficiency correction to account for resonant structures in the decays.