Measurement of the mass difference and relative production rate of the Ωb− and Ξb− baryons
【Abstract】 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.
【Journal】 Physical Review D(IF：4.4) Time：2023-09-20