Study of electromagnetic decays of orbitally excited ?c baryons

Abstract

Using 980 fb-1 of data collected with the Belle detector operating at the KEKB asymmetric-energy e+e- collider, we report a study of the electromagnetic decays of excited charmed baryons ?c(2790) and ?c(2815). A clear signal (8.6 standard deviations) is observed for ?c(2815)0??c0?, and we measure: B[?c(2815)0 ? ?c0?]B[?c(2815)0 ? ?c(2645)+?- ? ?c0?+?-]=0.41�0.05�0.03. We also present evidence (3.8 standard deviations) for the similar decay of the ?c(2790)0 and measure: B[?c(2790)0 ? ?c0?]B[?c(2790)0 ? ?c?+?- ? ?c+??-]=0.13�0.03�0.02. The first quoted uncertainties are statistical and the second systematic. We find no hint of the analogous decays of the ?c(2815)+ and ?c(2790)+ baryons and set upper limits at the 90% confidence level of: B[?c(2815)+ ? ?c+?]B[?c(2815)+ ? ?c(2645)0?+ ? ?c+?-?+]<0.09, and B[?c(2790)+ ? ?c+?]B[?c(2790)+ ? ?c?0?+ ? ?c0??+]<0.06. Approximate values of the partial widths of the decays are extracted, which can be used to discriminate between models of the underlying quark structure of these excited states. � 2020 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the "https://creativecommons.org/licenses/by/4.0/"Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP3.