Charm-strange baryon strong decays in a chiral quark model

Abstract

The strong decays of charm-strange baryons up to N=2 shell are studied in a chiral quark model. The theoretical predictions for the well determined charm-strange baryons, $Ξ_c^*(2645)$, $Ξ_c(2790)$ and $Ξ_c(2815)$, are in good agreement with the experimental data. This model is also extended to analyze the strong decays of the other newly observed charm-strange baryons $Ξ_c(2930)$, $Ξ_c(2980)$, $Ξ_c(3055)$, $Ξ_c(3080)$ and $Ξ_c(3123)$. Our predictions are given as follows. (i) $Ξ_c(2930)$ might be the first $P$-wave excitation of $Ξ_c'$ with $J^P=1/2^-$, favors the $|Ξ_c'\ ^2P_λ1/2^->$ or $|Ξ_c'\ ^4P_λ1/2^->$ state. (ii) $Ξ_c(2980)$ might correspond to two overlapping $P$-wave states $|Ξ_c'\ ^2P_ρ1/2^->$ and $|Ξ_c'\ ^2P_ρ3/2^->$, respectively. The $Ξ_c(2980)$ observed in the $Λ_c^+\bar{K}π$ final state is most likely to be the $|Ξ_c'\ ^2P_ρ1/2^->$ state, while the narrower resonance with a mass $m\simeq 2.97$ GeV observed in the $Ξ_c^*(2645)π$ channel favors to be assigned to the $|Ξ_c'\ ^2P_ρ3/2^->$ state. (iii) $Ξ_c(3080)$ favors to be classified as the $|Ξ_c\ S_{ρρ} 1/2^+>$ state, i.e., the first radial excitation (2S) of $Ξ_c$. (iv) $Ξ_c(3055)$ is most likely to be the first $D$-wave excitation of $Ξ_c$ with $J^P=3/2^+$, favors the $|Ξ_c\ ^2D_{λλ} 3/2^+>$ state. (v) $Ξ_c(3123)$ might be assigned to the $|Ξ_c'\ ^4D_{λλ} 3/2^+>$, $|Ξ_c'\ ^4D_{λλ} 5/2^+>$, or $|Ξ_c\ ^2D_{ρρ} 5/2^+>$ state. As a by-product, we calculate the strong decays of the bottom baryons $Σ_b^{\pm}$, $Σ_b^{*\pm}$ and $Ξ_b^*$, which are in good agreement with the recent observations as well.