Measurement of indirect CP asymmetries in D 0 → K - K + and D 0 → π - π + decays using semileptonic B decays

Abstract

Time-dependent CP asymmetries in the decay rates of the singly Cabibbo-suppressed decays D0→ K−K+ and D0→ π −π + are measured in pp collision data corresponding to an integrated luminosity of 3.0 fb−1 collected by the LHCb experiment. The D0 mesons are produced in semileptonic b-hadron decays, where the charge of the accompanying muon is used to determine the initial state as D0 or D0 . The asymmetries in effective lifetimes between D0 and D0 decays, which are sensitive to indirect CP violation, are determined to be AΓ(K−K+) = (−0.134 ± 0.077 +0.026 −0.034)% , AΓ(π −π +) = (−0.092 ± 0.145 +0.025 −0.033)% , where the first uncertainties are statistical and the second systematic. This result is in agreement with previous measurements and with the hypothesis of no indirect CP violation in D0 decays.