Observation of the decay B s 0 → K 0 p p ¯ and measurement of the B s 0 → K 0 p p ¯ branching fractions

Abstract

A study of the charmless baryonic decays B s 0 → K 0 p p ¯ is presented, where B s 0 denotes either a B0 or a B s 0 meson. The analysis is based on proton-proton collision data collected by the LHCb experiment at centre-of-mass energies of 7, 8, and 13 TeV, corresponding to an integrated luminosity of 9 fb−1. The decay B s 0 → K 0 p p ¯ is observed for the first time, with a measured branching fraction of (9.14 ± 1.69 ± 0.90 ± 0.33 ± 0.20) × 10−7 and a significance of 5.6σ. The uncertainties respectively account for statistical and systematic contributions, the precision of the branching fraction of the normalisation channel B0 → K0π+π− and the fragmentation fraction ratio fs/fd. The branching fraction determined for B 0 → K 0 p p ¯ is (2.82 ± 0.08 ± 0.12 ± 0.10) × 10−6, which is the most precise measurement to date.