Measurements of Direct CP-Violating Asymmetries in Charmless Decays of Bottom Baryons

We report final measurements of direct $mathit{CP}$--violating asymmetries in charmless decays of neutral bottom hadrons to pairs of charged hadrons with the upgraded Collider Detector at the Fermilab Tevatron. Using the complete $sqrt{s}=1.96$ TeV proton-antiproton collisions data set, corresponding to 9.3 fb$^{-1}$ of integrated luminosity, we measure $mathcal{A}(Lambda^0_b rightarrow ppi^{-}) = +0.06 pm 0.07mathrm{(stat)} pm 0.03mathrm{(syst)}$ and $mathcal{A}(Lambda^0_b rightarrow pK^{-}) = -0.10 pm 0.08mathrm{(stat)} pm 0.04mathrm{(syst)}$, compatible with no asymmetry. In addition we measure the $mathit{CP}$--violating asymmetries in $B^0_s rightarrow K^{-}pi^{+}$ and $B^0 rightarrow K^{+}pi^{-}$ decays to be $mathcal{A}(B^0_s rightarrow K^{-}pi^{+}) = +0.22 pm 0.07mathrm{stat)} pm 0.02mathrm{(syst)}$ and $mathcal{A}(B^0 rightarrow K^{+}pi^{-}) = -0.083pm 0.013 mathrm{(stat)} pm 0.004mathrm{(syst)}$, respectively, which are significantly different from zero and consistent with current world averages.