Strong decays of the Ξ(1620) as a ΛK¯ and ΣK¯ molecule

In this work, we study the strong decays of the newly observed Ξ(1620) assuming that it is a meson-baryon molecular state of ΛK¯ and ΣK¯. We consider four possible spin-parity assignments JP= 1 / 2 ± and 3 / 2 ± for the Ξ(1620) , and evaluate its partial decay width into Ξπ and Ξππ 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 K¯ Λ channel, while the rest is provided by the K¯ Σ channel. As a result, both channels are important in explaining the strong decay of the Ξ(1620). In addition, the transition Ξ(1620) → πΞ is the main decay channel in the JP= 1 / 2 - case, which almost saturates the total width. These information are helpful to further understand the nature of the Ξ(1620). © 2020, The Author(s).