Measurement of the Difference in $CP$-Violating Asymmetries in ${D}^{0}\ensuremath{\rightarrow}{K}^{+}{K}^{\ensuremath{-}}$ and ${D}^{0}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ Decays at CDF

Measurement of the Difference in $C P$ -Violating Asymmetries in $D^{0} \to K^{+} K^{-}$ and $D^{0} \to π^{+} π^{-}$ Decays at CDF

T. Aaltonen et al. (CDF Collaboration)

Phys. Rev. Lett. 109, 111801 – Published 11 September 2012

Abstract

We report a measurement of the difference ( $Δ A_{C P}$ ) between time-integrated $C P$ -violating asymmetries in $D^{0} \to K^{+} K^{-}$ and $D^{0} \to π^{+} π^{-}$ decays reconstructed in the full data set of proton-antiproton collisions collected by the Collider Detector at Fermilab, corresponding to $9.7 {fb}^{- 1}$ of integrated luminosity. The strong decay $D^{* +} \to D^{0} π^{+}$ is used to identify the charm meson at production as $D^{0}$ or ${\bar{D}}^{0}$ . We measure $Δ A_{C P} = [- 0.62 \pm 0.21 (stat) \pm 0.10 (syst)] %$ , which differs from zero by 2.7 Gaussian standard deviations. This result supports similar evidence for $C P$ violation in charm-quark decays obtained in proton-proton collisions.