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→Ξ0cγ, and we measure: B[Ξc(2815)0→Ξ0cγ]/B[Ξc(2815)0→Ξc(2645)+π−→Ξ0cπ+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→Ξ0cγ]/B[Ξc(2790)0→Ξ′+cπ−→Ξ+cγπ−]=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)+→Ξ+cγ]/B[Ξc(2815)+→Ξc(2645)0π+→Ξ+cπ−π+]<0.09, and B[Ξc(2790)+→Ξ+cγ]/B[Ξc(2790)+→Ξ′0cπ+→Ξ0cγπ+]<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.
Study of Electromagnetic Decays of Orbitally Excited Ξc Baryons
F. Tenchini;
2020-01-01
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} Ξc(2790) and Ξc(2815). A clear signal (8.6 standard deviations) is observed for Ξc(2815)0→Ξ0cγ, and we measure: B[Ξc(2815)0→Ξ0cγ]/B[Ξc(2815)0→Ξc(2645)+π−→Ξ0cπ+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→Ξ0cγ]/B[Ξc(2790)0→Ξ′+cπ−→Ξ+cγπ−]=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)+→Ξ+cγ]/B[Ξc(2815)+→Ξc(2645)0π+→Ξ+cπ−π+]<0.09, and B[Ξc(2790)+→Ξ+cγ]/B[Ξc(2790)+→Ξ′0cπ+→Ξ0cγπ+]<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.| File | Dimensione | Formato | |
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PhysRevD.102.071103.pdf
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