Probing the inner structures of the observed $\Xi_b$ and $\Xi_b'$ resonances

Abstract

To shed light on the inner structure of the observed single-bottom strange baryons, in this work we systematically study the Okubo-Zweig-Iizuka allowed strong decay properties of $1P$- and $2S$-wave $\Xi_b$ and $\Xi_b'$ baryons within the $j-j$ coupling scheme in the framework of the quark pair creation model. For a comparison, we also give the predictions of the chiral quark model. The calculations indicate that: (i) The $1P$-wave $\lambda$-mode $\Xi_b$ states $\Xi_b|J^P=1/2^-,1\rangle_{\lambda}$ and $\Xi_b|J^P=3/2^-,1\rangle_{\lambda}$ are highly promising candidates for the observed state $\Xi_b(6087)$ and $\Xi_b(6095)/\Xi_b(6100)$, respectively. The $1P$-wave $\rho$-mode $\Xi_b$ states $\Xi_b|J^P=3/2^-,2\rangle_{\rho}$ and $\Xi_b|J^P=5/2^-,2\rangle_{\rho}$ are likely candidates for the state $\Xi_b(6227)$. Meanwhile, we cannot rule out the possibility that $\Xi_b(6227)$ could be a candidate of the $1P$-wave $\lambda$-mode $\Xi_b'$ state $\Xi_b'|J^P=3/2^-,2\rangle_{\lambda}$ or $\Xi_b'|J^P=5/2^-,2\rangle_{\lambda}$. (ii) For the other $1P$-wave $\rho$-mode $\Xi_b$ states and $1P$-wave $\lambda$-mode $\Xi_b'$ states, they may be moderate states with a width of several tens of MeV. Their main decay channels are $\Xi_b\pi$, $\Xi_b'\pi$, $\Xi_b^*\pi$ or $\Lambda_b\bar{K}$. The width of the $1P$-wave $\rho$-mode $\Xi_b'$ states are slightly broader, approximately several tens to over one hundred MeV, and the dominant decay channels are $\Xi_b'\pi$, $\Xi_b^*\pi$, $\Sigma_bK$ or $\Sigma_b^*K$. (iii) The $2S$-wave $\lambda$-mode $\Xi_b$ and $\Xi_b'$ states are most likely to be relatively narrow state with a width of only a few to around ten MeV, and they mainly decay into $\Xi_b'\pi$ or $\Xi_b^*\pi$. In addition, the $2S$-wave $\lambda$-mode $\Xi_b'$ states may also mainly decay into the $1P$-wave $\Xi_b$ baryon via the pionic decay processes.