Study of b-hadron decays to Λc+h−h′− final states

Decays of Ξ_b⁻ and Ω_b⁻ baryons to Λ_c⁺h⁻h^′− final states, with h⁻h^′− being π⁻π⁻, K⁻π⁻ and K⁻K⁻ meson pairs, are searched for using data collected with the LHCb detector. The data sample studied corresponds to an integrated luminosity of 8.7 fb⁻¹ of pp collisions collected at centre-of-mass energies s = 7, 8 and 13 TeV. The products of the relative branching fractions and fragmentation fractions for each signal mode, relative to the B⁻→Λ_c⁺p¯π⁻ mode, are measured, with Ξ_b⁻→Λ_c⁺K⁻π⁻, Ξ_b⁻→Λ_c⁺K⁻K⁻ and Ω_b⁻→Λ_c⁺K⁻K⁻ decays being observed at over 5 σ significance. The Ξ_b⁻→Λ_c⁺K⁻π⁻ mode is also used to measure the Ξ_b⁻ production asymmetry, which is found to be consistent with zero. In addition, the B⁻→Λ_c⁺p¯K⁻ decay is observed for the first time, and its branching fraction is measured relative to that of the B⁻→Λ_c⁺p¯π⁻ mode.