Measurement of the charm mixing parameter yCP- yCPKπ using two-body D0 meson decays

Abstract

A measurement of the ratios of the effective decay widths of D0→π-π+ and D0→K-K+ decays over that of D0→K-π+ decays is performed with the LHCb experiment using proton-proton collisions at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 6 fb-1. These observables give access to the charm mixing parameters yCPππ-yCPKπ and yCPKK-yCPKπ, and are measured as yCPππ-yCPKπ=(6.57±0.53±0.16)×10-3, yCPKK-yCPKπ=(7.08±0.30±0.14)×10-3, where the first uncertainties are statistical and the second systematic. The combination of the two measurements is yCP-yCPKπ=(6.96±0.26±0.13)×10-3, which is four times more precise than the previous world average.