Quantum numbers of excited $Ξ_c^\prime$ and $Ω_c$ baryons and the $P$-wave $Σ_c$ 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 $Σ_c$, four $Ξ_c^\prime$, and five $Ω_c$ states are expected to be experimentally resolvable. The similar mass-splitting patterns of $Ξ_c(2882)$, $Ξ_c(2923)$, $Ξ_c(2939)$, and $Ξ_c(2965)$ and of $Ω_c(3000)$, $Ω_c(3050)$, $Ω_c(3066)$, and $Ω_c(3090)$, 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 $Ω_c(3119)$ as a predominantly $ρ$-mode excitation with $J^P=3/2^-$. We also predict the masses, widths, and dominant decay modes of four resolvable $P$-wave $Σ_c$ states, which may overlap within the observed $Σ_c(2800)$ and $Σ_c(2900)$ structures. Precision spectroscopy of the narrow $Ξ_c$ and $Ω_c$ states thus provides a route to resolving the $P$-wave $Σ_c$ spectrum.