Study of electromagnetic decays of orbitally excited Ξc baryons
© 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. 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 Ξc(2790) and Ξc(2815). A clear signal (8.6 standard deviations) is observed for Ξc(2815)0→Ξc0γ, and we measure: B[Ξc(2815)0 → Ξc0γ]B[Ξc(2815)0 → Ξc(2645)+π- → Ξc0π+π-]=0.41±0.05±0.03. We also present evidence (3.8 standard deviations) for the similar decay of the Ξc(2790)0 and measure: B[Ξc(2790)0 → Ξc0γ]B[Ξc(2790)0 → Ξc′+π- → Ξc+γπ-]=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 Ξc(2815)+ and Ξc(2790)+ baryons and set upper limits at the 90% confidence level of: B[Ξc(2815)+ → Ξc+γ]B[Ξc(2815)+ → Ξc(2645)0π+ → Ξc+π-π+]<0.09, and B[Ξc(2790)+ → Ξc+γ]B[Ξc(2790)+ → Ξc′0π+ → Ξc0γπ+]<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.
Physical Review D
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