CP Violation in the D0 → p+p- Decay at CDF

We report a measurement of the CP violating asymmetry in $D^0 opi^+pi^-$ decays using approximately 215,000 decays reconstructed in about $5.94$ fb$^{-1}$ of CDF data. We use the strong $D^{star +} o D^0pi^+$ decay ("$D^{star}$ tag") to identify the flavor of the charmed meson at production time and exploit CP-conserving strong $car{c}$ pair-production in $par{p}$ collisions. Higher statistic samples of Cabibbo-favored $D^0 o K^-pi^+$ decays with and without $D^{star}$ tag are used to highly suppress systematic uncertainties due to detector effects. The result, $Acp(D^0 o pi^{+}pi^{-}) = igl[0.22pm0.24statpm0.11systigr]%$, is the world's most precise measurement to date and it is fully consistent with no CP violation.