Study of Λ b 0 and Ξ b 0 Decays to Λ h + h ′ − and Evidence for C P Violation in Λ b 0 → Λ K + K − Decays

: A study of Λ_{b}^{0} and Ξ_{b}^{0} decays to Λh^{+}h^{'-} (h^{(')}=π,K) is performed using pp collision data collected by the LHCb experiment during LHC Runs 1-2, corresponding to an integrated luminosity of 9  fb^{-1}. The branching fractions for these decays are measured using the Λ_{b}^{0}→Λ_{c}^{+}(→Λπ^{+})π^{-} decay as a control channel. The decays Λ_{b}^{0}→Λπ^{+}π^{-} and Ξ_{b}^{0}→ΛK^{-}π^{+} are observed for the first time. For decay modes with sufficient signal yields, CP asymmetries are measured in the full and localized regions of the final-state phase space. Evidence is found for CP violation in the Λ_{b}^{0}→ΛK^{+}K^{-} decay, interpreted as originating primarily from an asymmetric Λ_{b}^{0}→N^{*+}K^{-} decay amplitude. The measured CP asymmetries for other decays are compatible with zero.