Ξ c and Ξ b excited states within a SU (6) lsf× HQSS model

Abstract

We study odd parity J= 1 / 2 and J= 3 / 2 Ξ resonances using a unitarized coupled-channel framework based on a SU (6) × HQSS-extended Weinberg–Tomozawa baryon–meson interaction, while paying a special attention to the renormalization procedure. We predict a large molecular Λ K¯ component for the Ξ (2790) with a dominant 0 light-degree-of-freedom spin configuration. We discuss the differences between the 3 / 2 Λ (2625) and Ξ (2815) states, and conclude that they cannot be SU(3) siblings, whereas we predict the existence of other Ξ -states, one of them related to the two-pole structure of the Λ (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 Ξ (2930) and Ξ (2970) , respectively. Within this picture, the Ξ (2930) would be part of a SU(3) sextet, containing either the Ω (3090) or the Ω (3119) , and that would be completed by the Σ (2800). Moreover, we identify a J= 1 / 2 sextet with the Ξ (6227) state and the recently discovered Σ (6097). Assuming the equal spacing rule and to complete this multiplet, we predict the existence of a J= 1 / 2 Ω odd parity state, with a mass of 6360 MeV and that should be seen in the Ξ K¯ channel.