Strong decays of the ${\Xi }_b(6227)$ as a ${\Sigma }_b\bar{K}$ molecule

Abstract

We study the strong decays of the newly observed ${\Xi }_b(6227)$ assuming that it is a pure ${\Sigma }_b\bar{K}$ molecular state. Considering four possible spin-parity assingments $J^P=1/2^{\pm }$ and $3/2^{\pm }$, the partial decay widths of the ${\Sigma }_b\bar{K}$ molecular state into ${\Lambda }_b\bar{K}$, ${\Xi }_b\pi$, and ${\Xi }_b^{{}^{\prime }}\pi$ final states through hadronic loops are evaluated with the help of the effective Lagrangians. In comparison with the LHCb data, the spin-party $1/2^{-}$ assignment is preferred while those of $J^P=1/2^{+}$ and $J^P=3/2^{\pm }$ are disfavored. In addition, we show that the two allowed decay modes ${\Lambda }_b\bar{K}$ and ${\Xi }_b\pi$ of the ${\Xi }_b(6227)$, being a $S$-wave ${\Sigma }_b\bar{K}$ molecular state, have almost equal branching ratios, consistent with the data.