Measurement of indirect CP asymmetries in D0 → K−K+ and D0 → π −π + decays using semileptonic B decays

Abstract

Time-dependent CP asymmetries in the decay rates of the singly Cabibbosuppressed 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 D 0 . The asymmetries in effective lifetimes between D0 and D 0 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 dec