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

Abstract

We report a measurement of the indirect CP-violating asymmetries ($A_{\Gamma }$) between effective lifetimes of anticharm and charm mesons reconstructed in $D^0\to K^{+}{K}^{-}$ and $D^0\to {\pi }^{+}{\pi }^{-}$ 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 $D^{\ast +}\to D^0{\pi }^{+}$ is used to identify the meson at production as $D^0$ or ${\overline{D}}^0$. We statistically subtract $D^0$ and ${\overline{D}}^0$ mesons originating from $b$-hadron decays and measure the yield asymmetry between anticharm and charm decays as a function of decay time. We measure $A_{\Gamma }(K^{+}{K}^{-})=(-0.19\pm 0.15(stat)\pm 0.04(syst))\%$ and $A_{\Gamma }({\pi }^{+}{\pi }^{-})=(-0.01\pm 0.18(stat)\pm 0.03(syst))\%$. The results are consistent with the hypothesis of CP symmetry and their combination yields $A_{\Gamma }=(-0.12\pm 0.12)\%$.

Comments: 8 pages, 3 figures, version published by Phys. Rev. D