Measurement of $CP$-violation asymmetries in ${D}^{0}\ensuremath{\rightarrow}{K}_{S}^{0}{\ensuremath{\pi}}^{\mathbf{+}}{\ensuremath{\pi}}^{\mathbf{\ensuremath{-}}}$

Measurement of $C P$ -violation asymmetries in $D^{0} \to K_{S}^{0} π^{+} π^{-}$

T. Aaltonen et al. (CDF Collaboration)

Phys. Rev. D 86, 032007 – Published 13 August 2012

Abstract

We report a measurement of time-integrated $C P$ -violation asymmetries in the resonant substructure of the three-body decay $D^{0} \to K_{S}^{0} π^{+} π^{-}$ using CDF II data corresponding to $6.0 {fb}^{- 1}$ of integrated luminosity from Tevatron $p \bar{p}$ collisions at $\sqrt{s} = 1.96 TeV$ . The charm mesons used in this analysis come from $D^{* +} (2010) \to D^{0} π^{+}$ and $D^{* -} (2010) \to {\bar{D}}^{0} π^{-}$ , where the production flavor of the charm meson is determined by the charge of the accompanying pion. We apply a Dalitz-amplitude analysis for the description of the dynamic decay structure and use two complementary approaches, namely, a full Dalitz-plot fit employing the isobar model for the contributing resonances and a model-independent bin-by-bin comparison of the $D^{0}$ and ${\bar{D}}^{0}$ Dalitz plots. We find no $C P$ -violation effects and measure an asymmetry of $A_{C P} = (- 0.05 \pm 0.57 (stat) \pm 0.54 (syst)) %$ for the overall integrated $C P$ -violation asymmetry, consistent with the standard model prediction.