${\Xi }_c$ and ${\Xi }_b$ excited states within a ${\mathrm{SU}(6)}_{\mathrm{lsf}}\times$HQSS model

Abstract

We study odd parity $J=1/2$ and $J=3/2$ ${\Xi }_c$ resonances using a unitarized coupled-channel framework based on a ${\mathrm{SU}(6)}_{\mathrm{lsf}}\times$HQSS-extended Weinberg-Tomozawa baryon-meson interaction, while paying a special attention to the renormalization procedure. We predict a large molecular ${\Lambda }_c\bar{K}$ component for the ${\Xi }_c(2790)$ with a dominant $0^{-}$ light-degree-of-freedom spin configuration. We discuss the differences between the $3/2^{-}$ ${\Lambda }_c(2625)$ and ${\Xi }_c(2815)$ states, and conclude that they cannot be SU(3) siblings, whereas we predict the existence of other ${\Xi }_c-$states, two of them related to the two-pole structure of the ${\Lambda }_c(2595)$. It is of particular interest a pair of $J=1/2$ and $J=3/2$ poles, which form a HQSS doublet and that we tentatively assign to the ${\Xi }_c(2930)$ and ${\Xi }_c(2970)$, respectively. Within this picture, the ${\Xi }_c(2930)$ would be part of a SU(3) sextet, containing either the ${\Omega }_c(3090)$ or the ${\Omega }_c(3119)$, and that would be completed by the ${\Sigma }_c(2800)$. Moreover, we identify a $J=1/2$ sextet with the ${\Xi }_b(6227)$ state and the recently discovered ${\Sigma }_b(6097)$. Assuming the equal spacing rule and to complete this multiplet, we predict the existence of a $J=1/2$ ${\Omega }_b$ odd parity state, with a mass of 6360 MeV and that should be seen in the ${\Xi }_b\bar{K}$ channel.

Comments: 13 pages, 5 figures, 4 tables