Measurement of CP observables in B^± → D^(⁎)K^± and B^± → D^(⁎)π^± decays

Measurements of CP observables in B^±→D^(⁎)K^± and B^±→D^(⁎)π^± decays are presented, where D^(⁎) indicates a neutral D or D^⁎ meson that is an admixture of D^(⁎)0 and D¯^(⁎)0 states. Decays of the D^⁎ meson to the Dπ⁰ and Dγ final states are partially reconstructed without inclusion of the neutral pion or photon, resulting in distinctive shapes in the B candidate invariant mass distribution. Decays of the D meson are fully reconstructed in the K^±π^∓, K⁺K⁻ and π⁺π⁻ final states. The analysis uses a sample of charged B mesons produced in pp collisions collected by the LHCb experiment, corresponding to an integrated luminosity of 2.0, 1.0 and 2.0 fb⁻¹ taken at centre-of-mass energies of s=7, 8 and 13 TeV, respectively. The study of B^±→D^⁎K^± and B^±→D^⁎π^± decays using a partial reconstruction method is the first of its kind, while the measurement of B^±→DK^± and B^±→Dπ^± decays is an update of previous LHCb measurements. The B^±→DK^± results are the most precise to date.