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

• Main Authors: J. Nieves, R. Pavao, L. Tolos
• Format: Article
• Language: English
• Published: SpringerOpen 2020-01-01
• Series: European Physical Journal C: Particles and Fields
• Online Access: https://doi.org/10.1140/epjc/s10052-019-7568-8

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