Study of the kinematic dependences of Λb⁰ production in pp collisions and a measurement of the Λb⁰  → Λc⁺ π⁻ branching fraction

The kinematic dependences of the relative production rates, (formula presented), of Λ ⁰ _b baryons and B ⁰ mesons are measured using Λ ⁰ _b  → Λ _c ⁺ π ⁻ and (formula presented) decays. The measurements use proton-proton collision data, corresponding to an integrated luminosity of 1 fb ⁻¹ at a centre-of-mass energy of 7 TeV, recorded in the forward region with the LHCb experiment. The relative production rates are observed to depend on the transverse momentum, p _T, and pseudorapidity, η, of the beauty hadron, in the studied kinematic region 1.5 < p _T < 40 GeV/c and 2 < η < 5. Using a previous LHCb measurement of (formula presented) in semileptonic decays, the branching fraction (formula presented) is obtained, where the first uncertainty is statistical, the second is systematic, the third is from the previous LHCb measurement of (formula presented) and the fourth is due to the (formula presented) branching fraction. This is the most precise measurement of a Λ _b ⁰ branching fraction to date.