Observations of Λ<inf>b</inf>⁰ → ΛK⁺π⁻ and Λ<inf>b</inf>⁰ → ΛK⁺ K⁻ decays and searches for other Λ<inf>b</inf>⁰ and Ξ<inf>b</inf>⁰ decays to Λh⁺ h′⁻ final states

A search is performed for the charmless three-body decays of the Λ _b ⁰ and Ξ _b ⁰ baryons to the final states Λh ⁺h′ ⁻, where h ⁽′ ⁾ = π or K. The analysis is based on a data sample, corresponding to an integrated luminosity of 3 fb ⁻¹ of pp collisions, collected by the LHCb experiment. The Λ _b ⁰ → ΛK ⁺π ⁻ and Λ _b ⁰ → ΛK ⁺K ⁻ decays are observed for the first time and their branching fractions and CP asymmetry parameters are measured. Evidence is seen for the Λ _b ⁰ → Λπ ⁺π ⁻ decay and limits are set on the branching fractions of Ξ _b ⁰ baryon decays to the Λh ⁺h′ ⁻ final states.