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, $\Xi_c^*(2645)$, $\Xi_c(2790)$ and $\Xi_c(2815)$, 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 $\Xi_c(2930)$, $\Xi_c(2980)$, $\Xi_c(3055)$, $\Xi_c(3080)$ and $\Xi_c(3123)$. Our predictions are given as follows. (i) $\Xi_c(2930)$ might be the first $P$-wave excitation of $\Xi_c'$ with $J^P=1/2^-$, favors the $|\Xi_c'\ ^2P_\lambda 1/2^->$ or $|\Xi_c'\ ^4P_\lambda 1/2^->$ state. (ii) $\Xi_c(2980)$ might correspond to two overlapping $P$-wave states $|\Xi_c'\ ^2P_\rho 1/2^->$ and $|\Xi_c'\ ^2P_\rho 3/2^->$, respectively. The $\Xi_c(2980)$ observed in the $\Lambda_c^+\bar{K}\pi$ final state is most likely to be the $|\Xi_c'\ ^2P_\rho 1/2^->$ state, while the narrower resonance with a mass $m\simeq 2.97$ GeV observed in the $\Xi_c^*(2645)\pi$ channel favors to be assigned to the $|\Xi_c'\ ^2P_\rho 3/2^->$ state. (iii) $\Xi_c(3080)$ favors to be classified as the $|\Xi_c\ S_{\rho\rho} 1/2^+>$ state, i.e., the first radial excitation (2S) of $\Xi_c$. (iv) $\Xi_c(3055)$ is most likely to be the first $D$-wave excitation of $\Xi_c$ with $J^P=3/2^+$, favors the $|\Xi_c\ ^2D_{\lambda\lambda} 3/2^+>$ state. (v) $\Xi_c(3123)$ might be assigned to the $|\Xi_c'\ ^4D_{\lambda\lambda} 3/2^+>$, $|\Xi_c'\ ^4D_{\lambda\lambda} 5/2^+>$, or $|\Xi_c\ ^2D_{\rho\rho} 5/2^+>$ state. As a by-product, we calculate the strong decays of the bottom baryons $\Sigma_b^{\pm}$, $\Sigma_b^{*\pm}$ and $\Xi_b^*$, which are in good agreement with the recent observations as well.