Updated measurement of decay-time-dependent CP asymmetries in D^{0}→K^{+}K^{-} and D^{0}→π^{+}π^{-} decays

Abstract

A search for decay-time-dependent charge-parity (CP) asymmetry in D^{0}→K^{+}K^{-} and D^{0}→π^{+}π^{-} decays is performed at the LHCb experiment using proton-proton collision data recorded at a center-of-mass energy of 13 TeV, and corresponding to an integrated luminosity of 5.4 fb^{-1}. The D^{0} 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 D^{0} and D[over ¯]^{0} mesons are determined to be A_{Γ}(K^{+}K^{-})=(-4.3±3.6±0.5)×10^{-4} and A_{Γ}(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 A_{Γ}(K^{+}K^{-})=(-4.4±2.3±0.6)×10^{-4} and A_{Γ}(π^{+}π^{-})=(2.5±4.3±0.7)×10^{-4}.