Observation of an excited charm baryon Ωc* decaying to Ωc0γ

We report the first observation of an excited singly charmed baryon Ωc* (css) in the radiative decay Ωc0γ, where the Ωc0 baryon is reconstructed in the decays to the final states Ω-π+, Ω-π+π0, Ω-π+π-π+, and Ξ-K-π+π+. This analysis is performed using a data set of 230.7fb-1 collected by the BABAR detector at the PEP-II asymmetric-energy B factory at the Stanford Linear Accelerator Center. The mass difference between the Ωc* and the Ωc0 baryons is measured to be 70.8±1. 0(stat)±1.1(syst)MeV/c2. We also measure the ratio of inclusive production cross sections of Ωc* and Ωc0 in e+e- annihilation. © 2006 The American Physical Society.