CDF results on CP violation in charm

Abstract

I discuss the measurement of CP-violating asymmetries ($A_{\Gamma}$) between effective lifetimes of $D^0$ or $\bar{D}^0$ mesons. Fully reconstructed $D^0\to K^+ K^-$ and $D^0\to \pi^+\pi^-$ decays collected in $p\bar{p}$ collisions by the Collider Detector at Fermilab experiment and corresponding to a data set of $9.7$~fb$^{-1}$ of integrated luminosity are used. The flavor of the charm meson at production is determined by exploiting the decay $D^{*+} \to D^0 \pi^+$. Contamination from mesons originated in $b$-hadron decays is subtracted from the sample. Signal yields as functions of the observed decay-time distributions are determined using likelihood fits and used to measure the asymmetries. The results, $A_\Gamma (K^+K^-) = \bigl(-1.9 \pm 1.5~(stat) \pm 0.4~(syst) \bigr)\times10^{-3}$ and $A_\Gamma (\pi^+\pi^-)= \bigl(-0.1 \pm 1.8~(stat) \pm 0.3~(syst) \bigr)\times10^{-3}$, and their combination, $A_\Gamma = \bigl(-1.2 \pm 1.2 \bigr)\times10^{-3}$, are consistent with the SM predictions and other experimental determinations.