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, ${\Xi }_c^{\ast }(2645)$, ${\Xi }_c(2790)$ 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 ${\Xi }_c^{\prime }$ with $J^P=1/2^{-}$, favors the $|{\Xi }_c^{\prime }{}^2{P}_{\lambda }1/2^{-}>$ or $|{\Xi }_c^{\prime }{}^4{P}_{\lambda }1/2^{-}>$ state. (ii) ${\Xi }_c(2980)$ might correspond to two overlapping $P$-wave states $|{\Xi }_c^{\prime }{}^2{P}_{\rho }1/2^{-}>$ and $|{\Xi }_c^{\prime }{}^2{P}_{\rho }3/2^{-}>$, respectively. The ${\Xi }_c(2980)$ observed in the ${\Lambda }_c^{+}\bar{K}\pi$ final state is most likely to be the $|{\Xi }_c^{\prime }{}^2{P}_{\rho }1/2^{-}>$ state, while the narrower resonance with a mass $m\simeq 2.97$ GeV observed in the ${\Xi }_c^{\ast }(2645)\pi$ channel favors to be assigned to the $|{\Xi }_c^{\prime }{}^2{P}_{\rho }3/2^{-}>$ 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 $|{\Xi }_c{}^2{D}_{\lambda \lambda }3/2^{+}>$ state. (v) ${\Xi }_c(3123)$ might be assigned to the $|{\Xi }_c^{\prime }{}^4{D}_{\lambda \lambda }3/2^{+}>$, $|{\Xi }_c^{\prime }{}^4{D}_{\lambda \lambda }5/2^{+}>$, or $|{\Xi }_c{}^2{D}_{\rho \rho }5/2^{+}>$ state. As a by-product, we calculate the strong decays of the bottom baryons ${\Sigma }_b^{\pm }$, ${\Sigma }_b^{\ast \pm }$ and ${\Xi }_b^{\ast }$, which are in good agreement with the recent observations as well.

Comments: 15 pages, 9 figures