Measurement of indirect CP-violating asymmetries in $D^0\to K^+K^-$ and $D^0\to \pi^+\pi^-$ decays at CDF

We report a measurement of the indirect CP-violating asymmetries (A(Gamma)) between effective lifetimes of anticharm and charm mesons reconstructed in D-0 --> K+K- and D-0 --> pi(+)pi(-) decays. We use the full data set of proton-antiproton collisions collected by the Collider Detector at Fermilab experiment and corresponding to 9.7 fb(-1) of integrated luminosity. The strong-interaction decay D*(+) --> D-0 pi(+) is used to identify the meson at production as D-0 or (D) over bar (0). We statistically subtract D-0 and (D) over bar (0) mesons originating from b-hadron decays and measure the yield asymmetry between anticharm and charm decays as a function of decay time. We measure A(Gamma)(K+K- ) = (-0.19 +/- 0.15(stat) +/- 0.04(syst))% and A(Gamma)(pi(+)pi(-)) = (- 0.01 +/- 0.18(stat) +/- 0.03(syst)%. The results are consistent with the hypothesis of CP symmetry and their combination yields A(Gamma) = (- 0.12 +/- 0.12)%.