Measurement of the mass difference and relative production rate of the ωb- and Ξb- baryons

The mass difference between the ωb- and Ξb- baryons is measured using proton-proton collision data collected by the LHCb experiment, corresponding to an integrated luminosity of 9 fb-1, and is found to be m(ωb-)-m(Ξb-)=248.54±0.51(stat)±0.38(syst) MeV/c2. The mass of the ωb- baryon is measured to be m(ωb-)=6045.9±0.5(stat)±0.6(syst) MeV/c2. This is the most precise determination of the ωb- mass to date. In addition, the production rate of ωb- baryons relative to that of Ξb- baryons is measured for the first time in pp collisions, using an LHCb dataset collected at a center-of-mass energy of 13 TeV and corresponding to an integrated luminosity of 6 fb-1. Reconstructing beauty baryons in the kinematic region 2<η<6 and pT<20 GeV/c with their decays to a J/ψ meson and a hyperon, the ratio fωb-fΞb-×B(ωb-→J/ψω-)B(Ξb-→J/ψΞ-)=0.120±0.008(stat)±0.008(syst), is obtained, where fωb- and fΞb- are the fragmentation fractions of b quarks into ωb- and Ξb- baryons, respectively, and B represents the branching fractions of their respective decays