Search for time-dependent CP violation in D0→K+K− and D0→π+π− decays

A search for time-dependent violation of the charge-parity symmetry in D0 → KþK− and D0 → πþπ− decays is performed at the LHCb experiment using proton-proton collision data recorded from 2015 to 2018 at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 6 fb−1. The D0 meson is required to originate from a Dð2010Þþ → D0πþ decay, such that its flavor at production is identified by the charge of the accompanying pion. The slope of the time-dependent asymmetry of the decay rates of D0 and D¯ 0 mesons into the final states under consideration is measured to be ΔYKþK− ¼ ð−2.3 1.5 0.3Þ × 10−4, ΔYπþπ− ¼ ð−4.0 2.8 0.4Þ × 10−4, where the first uncertainties are statistical and the second are systematic. These results are compatible with the conservation of the charge-parity symmetry at the level of 2 standard deviations and improve the precision by nearly a factor of 2.