Measurement of branching fractions and CP asymmetries in $ {\varLambda}_b^0\left({\varXi}_b^0\right)\to p{K}_{\textrm{S}}^0{h}^{-} $ decays

A study of ${\Lambda}_b^0$ and ${\Xi}_b^0$ baryon decays to the final states $p{K}_{\textrm{S}}^0{\pi}^{-}$ and $p{K}_{\textrm{S}}^0{K}^{-}$ is performed using pp collision data collected by the LHCb experiment, corresponding to an integrated luminosity of 9 fb − 1 . The decays ${\Lambda}_b^0\to p{K}_{\textrm{S}}^0{K}^{-}$ and ${\Xi}_b^0\to p{K}_{\textrm{S}}^0{K}^{-}$ are observed for the first time, with significances reaching eight standard deviations. The branching fractions and integrated CP asymmetries are measured for the ${\Lambda}_b^0\to p{K}_{\textrm{S}}^0{\pi}^{-}$ , ${\Lambda}_b^0\to p{K}_{\textrm{S}}^0{K}^{-}$ , and ${\Xi}_b^0\to p{K}_{\textrm{S}}^0{K}^{-}$ decays. For the decay ${\Lambda}_b^0\to p{K}_{\textrm{S}}^0{\pi}^{-}$ , the CP asymmetries are measured in different regions of the Dalitz plot. No evidence of CP violation is observed.