Strong decays of the $Ξ(1620)$ as a $Λ\bar{K}$ and $Σ\bar{K}$ molecule

In this work, we study the strong decays of the newly observed $Ξ(1620)^0$ assuming that it is a meson-baryon molecular state of $Λ\bar{K}$ and $Σ\bar{K}$. We consider four possible spin-parity assignments $J^P=1/2^{\pm}$ and $3/2^{\pm}$ for the $Ξ(1620)^0$, and evaluate its partial decay width into $Ξπ$ via hadronic loops with the help of effective Lagrangians. In comparison with the Belle data, the calculated decay width favors the spin-party assignment $1/2^-$ while the other spin-parity assignments do not yield a decay width consistent with data in the molecule picture. We find that about $52\%$-$68\%$ of the total width comes from the $\bar{K}Λ$ channel, while the rest is provided by the $\bar{K}Σ$ channel. As a result, both channels are important in explaining the strong decay of the $Ξ(1620)^0$. This information is helpful to further understand the nature of the $Ξ(1620)^0$.

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