Probing the inner structures of the observed ${\Xi }_b$ and ${\Xi }_b^{\prime }$ 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 ${\Xi }_b^{\prime }$ 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 ${\Xi }_b|J^P=1/2^{-},1{⟩}_{\lambda }$ and ${\Xi }_b|J^P=3/2^{-},1{⟩}_{\lambda }$ 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 ${\Xi }_b|J^P=3/2^{-},2{⟩}_{\rho }$ and ${\Xi }_b|J^P=5/2^{-},2{⟩}_{\rho }$ 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 ${\Xi }_b^{\prime }$ state ${\Xi }_b^{\prime }|J^P=3/2^{-},2{⟩}_{\lambda }$ or ${\Xi }_b^{\prime }|J^P=5/2^{-},2{⟩}_{\lambda }$. (ii) For the other $1P$-wave $\rho$-mode ${\Xi }_b$ states and $1P$-wave $\lambda$-mode ${\Xi }_b^{\prime }$ states, they may be moderate states with a width of several tens of MeV. Their main decay channels are ${\Xi }_b\pi$, ${\Xi }_b^{\prime }\pi$, ${\Xi }_b^{\ast }\pi$ or ${\Lambda }_b\bar{K}$. The width of the $1P$-wave $\rho$-mode ${\Xi }_b^{\prime }$ states are slightly broader, approximately several tens to over one hundred MeV, and the dominant decay channels are ${\Xi }_b^{\prime }\pi$, ${\Xi }_b^{\ast }\pi$, ${\Sigma }_{b}K$ or ${\Sigma }_b^{\ast }K$. (iii) The $2S$-wave $\lambda$-mode ${\Xi }_b$ and ${\Xi }_b^{\prime }$ 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 ${\Xi }_b^{\prime }\pi$ or ${\Xi }_b^{\ast }\pi$. In addition, the $2S$-wave $\lambda$-mode ${\Xi }_b^{\prime }$ states may also mainly decay into the $1P$-wave ${\Xi }_b$ baryon via the pionic decay processes.

Comments: 18 pages, 6 figures