Study of the kinematic dependences of Λ b 0 production in pp collisions and a measurement of the Λ b 0  →  Λ c + π − branching fraction

The kinematic dependences of the relative production rates, f Λ b 0 / f d , of Λ b 0 baryons and B 0 mesons are measured using Λ b 0  →  Λ c + π − and B ¯ 0 → D + π − 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 f Λ b 0 / f d in semileptonic decays, the branching fraction ℬ( Λ b 0  →  Λ c + π − ) = (4.30 ± 0.03 − 0.11 + 0.12  ± 0.26 ± 0.21) × 10 − 3 is obtained, where the first uncertainty is statistical, the second is systematic, the third is from the previous LHCb measurement of f Λ b 0 / f d and the fourth is due to the b B ¯ 0 → D + π − branching fraction. This is the most precise measurement of a Λ b 0 branching fraction to date.