Strong decays of the $$\varXi (1620)^0$$Ξ(1620)0 as a $$\varLambda {\bar{K}}$$ΛK¯ and $$\varSigma {\bar{K}}$$ΣK¯ molecule

In this work, we study the strong decays of the newly observed $$\varXi (1620)^0$$ assuming that it is a meson-baryon molecular state of $$\varLambda {\bar{K}}$$ and $$\varSigma {\bar{K}}$$ . We consider four possible spin-parity assignments $$J^P=1/2^{\pm }$$ and $$3/2^{\pm }$$ for the $$\varXi (1620)^0$$ , and evaluate its partial decay width into $$\varXi \pi $$ and $$\varXi \pi \pi $$ 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 $${\bar{K}}\varLambda $$ channel, while the rest is provided by the $${\bar{K}}\varSigma $$ channel. As a result, both channels are important in explaining the strong decay of the $$\varXi (1620)^0$$ . In addition, the transition $$\varXi (1620)^0\rightarrow \pi \varXi $$ is the main decay channel in the $$J^{P}=1/2^{-}$$ case, which almost saturates the total width. These information are helpful to further understand the nature of the $$\varXi (1620)^0$$ .