Observation of Cabibbo-suppressed two-body hadronic decays and precision mass measurement of the Ω°c baryon

Abstract

[Abstract] The first observation of the singly Cabibbo-suppressed Ω°c → Ω−K+ and Ω°c → Ξ−π+ decays is reported, using proton-proton collision data at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 5.4 fb¯¹ , collected with the LHCb detector between 2016 and 2018. The branching fraction ratios are measured to be B(Ω°c → Ω−K+) / B(Ω°c → Ω−π+) = [6.08 ± 0.51 (stat) ± 0.40 (syst)]%, B(Ω°c → Ξ−π+) / B(Ω°c → Ω−π+) = [15.81 ± 0.87 (stat) ± 0.44 (syst) ± 0.16 (ext)]%. In addition, using the Ω°c → Ω−π+ decay channel, the Ω°c baryon mass is measured to be M(Ω°c) = 2695.28 ± 0.07 (stat) ± 0.27 (syst) ± 0.30 (ext) MeV, improving the precision of the previous world average by a factor of 4.