Quantum numbers of excited ${\Xi }_c^{\prime }$ and ${\Omega }_c$ baryons and the $P$-wave ${\Sigma }_c$ spectrum

Abstract

Recent precision measurements of excited heavy baryons, combined with systematic theoretical studies, make it possible to resolve the fine structure of their spectra. We calculate the masses and strong-decay properties of the $P$-wave charmed baryons using QCD sum rules and light-cone sum rules within heavy quark effective theory (HQET). Although seven states are allowed in each flavor sector, we find that only four ${\Sigma }_c$, four ${\Xi }_c^{\prime }$, and five ${\Omega }_c$ states are expected to be experimentally resolvable. The similar mass-splitting patterns of ${\Xi }_c(2882)$, ${\Xi }_c(2923)$, ${\Xi }_c(2939)$, and ${\Xi }_c(2965)$ and of ${\Omega }_c(3000)$, ${\Omega }_c(3050)$, ${\Omega }_c(3066)$, and ${\Omega }_c(3090)$, together with our theoretical results, lead to the successive quantum-number assignments $J^P=1/2^{-},3/2^{-},3/2^{-}$, and $5/2^{-}$. We tentatively interpret ${\Omega }_c(3119)$ as a predominantly $\rho$-mode excitation with $J^P=3/2^{-}$. We also predict the masses, widths, and dominant decay modes of four resolvable $P$-wave ${\Sigma }_c$ states, which may overlap within the observed ${\Sigma }_c(2800)$ and ${\Sigma }_c(2900)$ structures. Precision spectroscopy of the narrow ${\Xi }_c$ and ${\Omega }_c$ states thus provides a route to resolving the $P$-wave ${\Sigma }_c$ spectrum.

Comments: 6 pages, 1 figure, 1 table, suggestions and comments welcome