Studying the $Ξ(2030)$ as a predominantly $\bar{K}^{*}Σ$ molecular state

Abstract

Since its discovery in 1977, the spin-parity of $Ξ(2030)$ has not been fully determined experimentally. The latest Particle Data Group (PDG) listing suggests it may be a baryon with $J=5/2$. Therefore, studying the mass spectrum and decay properties of $Ξ(2030)$ has become a current hot topic to definitively establish its spin-parity. As the three-quark model fails to explain $Ξ(2030)$, we previously proposed it may be a molecule primarily composed of $\bar{K}^{}Σ$ with $J^P=5/2^{+}$, based on its mass spectrum study. To verify its molecular state interpretation, this work proposes studying the strong decays of $Ξ(2030)$ assuming it is a $P$-wave $J^P=5/2^{+}$ meson-baryon molecule predominantly composed of $\bar{K}^{}Σ$. We calculated all experimentally measured two-body and three-body final state decay widths of $Ξ(2030)$, including $Ξ(2030) \to \bar{K}Λ, \bar{K}Σ, πΞ, πΞ^{*}$, and $Ξ(2030) \to ππΞ, π\bar{K}Σ, π\bar{K}Λ$. The results indicate that both the total decay width and partial decay widths agree well with experimental values within the error margins. This supports that $Ξ(2030)$ is a molecule with spin-parity $J^P = 5/2^{+}$, predominantly composed of $\bar{K}^{*}Σ$. Compared to the experimental central values, our results are slightly smaller, which suggests that $Ξ(2030)$ may contain additional components besides meson-baryon molecular components, such as three quark structures.