Observation of excited Ωc0 baryons in Ωb- → Ξc+ K-π- decays

The first observation of the Omega(-)(b) -> Xi(+)(c) K-pi(-) decay is reported using p p collision data at center of mass energies of 7, 8, and 13 TeV collected by the LHCb experiment, corresponding to an integrated luminosity of 9 fb(-1). Four excited Omega(0)(c) baryons are observed in the Xi K-+(c)- mass projection of the Omega(-)(b) -> Xi K-+(c)-pi(-) decays with the significance of each exceeding five standard deviations. They coincide with the states previously observed in prompt pp and e(+)e(-) production. Relative production rates, masses, and natural widths of the states are measured, and a test of spin hypotheses is performed. Moreover, the branching ratio of Omega(-)(b) -> Xi K-+(c)-pi(-) is measured relative to the Omega(-)(b) -> Omega(0)(c)pi(-) decay mode and a precise measurement of the Omega(-)(b) mass of 6044.3 +/- 1.2 +/- 1.1(-0.22)(+0.19) MeV is obtained.

Automated summary

The first observation of the Omega(-)(b) -> Xi(+)(c) K-pi(-) decay is reported using LHCb experiment data, measuring the excited Omega(0)(c) baryons and testing spin hypotheses. The study also measures relative production rates, masses, and natural widths of the states, as well as the branching ratio of Omega(-)(b) -> Xi K-+(c)-pi(-) decay mode in comparison to Omega(-)(b) -> Omega(0)(c)pi(-) decay mode, obtaining a precise measurement of the Omega(-)(b) mass.