Probing the inner structures of the observed $Ξ_b$ and $Ξ_b'$ resonances

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 $Ξ_b$ and $Ξ_b'$ 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 $λ$-mode $Ξ_b$ states $Ξ_b|J^P=1/2^-,1\rangle_λ$ and $Ξ_b|J^P=3/2^-,1\rangle_λ$ are highly promising candidates for the observed state $Ξ_b(6087)$ and $Ξ_b(6095)/Ξ_b(6100)$, respectively. The $1P$-wave $ρ$-mode $Ξ_b$ states $Ξ_b|J^P=3/2^-,2\rangle_ρ$ and $Ξ_b|J^P=5/2^-,2\rangle_ρ$ are likely candidates for the state $Ξ_b(6227)$. Meanwhile, we cannot rule out the possibility that $Ξ_b(6227)$ could be a candidate of the $1P$-wave $λ$-mode $Ξ_b'$ state $Ξ_b'|J^P=3/2^-,2\rangle_λ$ or $Ξ_b'|J^P=5/2^-,2\rangle_λ$. (ii) For the other $1P$-wave $ρ$-mode $Ξ_b$ states and $1P$-wave $λ$-mode $Ξ_b'$ states, they may be moderate states with a width of several tens of MeV. Their main decay channels are $Ξ_bπ$, $Ξ_b'π$, $Ξ_b^*π$ or $Λ_b\bar{K}$. The width of the $1P$-wave $ρ$-mode $Ξ_b'$ states are slightly broader, approximately several tens to over one hundred MeV, and the dominant decay channels are $Ξ_b'π$, $Ξ_b^*π$, $Σ_bK$ or $Σ_b^*K$. (iii) The $2S$-wave $λ$-mode $Ξ_b$ and $Ξ_b'$ 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 $Ξ_b'π$ or $Ξ_b^*π$. In addition, the $2S$-wave $λ$-mode $Ξ_b'$ states may also mainly decay into the $1P$-wave $Ξ_b$ baryon via the pionic decay processes.

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