$\Xi_c$ and $\Xi_b$ excited states within a ${\rm SU(6)}_{\rm lsf}\times$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 ${\rm SU(6)}_{\rm lsf}\times$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.