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

TL;DR

This study investigates the $ ext{Xi}(2030)$ baryon, proposing it as a $ar{K}^* ext{-} ext{Sigma}$ molecular state with $J^P=5/2^{+}$, and calculates decay widths that align with experimental data, supporting its molecular interpretation.

Contribution

It provides the first detailed decay analysis supporting $ ext{Xi}(2030)$ as a $ar{K}^* ext{-} ext{Sigma}$ molecular state with specific spin-parity, challenging the three-quark model.

Findings

Decay widths match experimental data within errors.

Supports $ ext{Xi}(2030)$ as a $ar{K}^* ext{-} ext{Sigma}$ molecule.

Indicates possible additional components beyond molecular structure.

Abstract

Since its discovery in 1977, the spin-parity of $\Xi(2030)$ 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 $\Xi(2030)$ has become a current hot topic to definitively establish its spin-parity. As the three-quark model fails to explain $\Xi(2030)$, we previously proposed it may be a molecule primarily composed of $\bar{K}^{}\Sigma$ 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 $\Xi(2030)$ assuming it is a $P$-wave $J^P=5/2^{+}$ meson-baryon molecule predominantly composed of $\bar{K}^{}\Sigma$. We calculated all experimentally measured two-body and three-body final state decay widths of $\Xi(2030)$, including $\Xi(2030) \to \bar{K}\Lambda, \bar{K}\Sigma, \pi\Xi, \pi\Xi^{*}$, and $\Xi(2030) \to \pi\pi\Xi, \pi\bar{K}\Sigma, \pi\bar{K}\Lambda$. 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 $\Xi(2030)$ is a molecule with spin-parity $J^P = 5/2^{+}$, predominantly composed of $\bar{K}^{*}\Sigma$. Compared to the experimental central values, our results are slightly smaller, which suggests that $\Xi(2030)$ may contain additional components besides meson-baryon molecular components, such as three quark structures.