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Article

Updated measurement of decay-time-dependent CP asymmetries in D0→K+K− and D0→π+π− decays

Borisyak M. A., Derkach D., Hushchyn M., Ustyuzhanin A., Chekalina V., Boldyrev A., Arzymatov K., Belavin V., Kazeev N., Maevskiy A., Ratnikov F., Рыжиков А. С., Baranov A., LHCb c.

A search for decay-time-dependent charge-parity (CP) asymmetry in D0→K+K− and D0→π+π− decays is performed at the LHCb experiment using proton-proton collision data recorded at a center-of-mass energy of 13TeV, and corresponding to an integrated luminosity of 5.4fb−1. The D0 mesons are required to originate from semileptonic decays of b hadrons, such that the charge of the muon identifies the flavor of the neutral D meson at production. The asymmetries in the effective decay widths of D0 and D¯¯¯¯0 mesons are determined to be AΓ(K+K−)=(−4.3±3.6±0.5)×10−4 and AΓ(π+π−)=(2.2±7.0±0.8)×10−4, where the uncertainties are statistical and systematic, respectively. The results are consistent with CP symmetry and, when combined with previous LHCb results, yield AΓ(K+K−)=(−4.4±2.3±0.6)×10−4 and AΓ(π+π−)=(2.5±4.3±0.7)×10−4.