Further understanding the nature of $\Omega(2012)$ within a chiral quark model

TL;DR

This study investigates the decay mechanisms and internal structure of the $ ext{Ω}(2012)$ baryon within a chiral quark model, focusing on three-body decays, coupled-channel effects, and the dominance of three-quark components.

Contribution

It provides a detailed analysis of the three-body decay processes and coupled-channel effects, offering insights into the baryon's structure and decay ratios within the chiral quark model.

Findings

The $ ext{Ω}(2012)$ has a sizeable decay rate into the $ ext{Ξ} ext{π}ar{ ext{K}}$ final state.

Predicted decay ratio $R_{ ext{Ξ}ar{ ext{K}}}^{ ext{Ξ} ext{π}ar{ ext{K}}}$ is close to experimental upper limit but smaller than recent measurements.

The $ ext{Ω}(2012)$ is predominantly a three-quark state with only about 16% molecular component.

Abstract

In our previous works, we have analyzed the two-body strong decays of the low-lying $\Omega$ baryon states within a chiral quark model. The results show that the $\Omega(2012)$ resonance favors the three-quark state with $J^P=3/2^-$ classified in the quark model. With this assignment, in the present work we further study the three-body strong decay $\Omega(2012)\to \Xi^*(1530)\bar{K} \to \Xi\pi\bar{K}$ and coupled-channel effects on $\Omega(2012)$ from nearby channels $\Xi \bar{K}$, $\Omega\eta$ and $\Xi^*(1530)\bar{K}$ within the chiral quark model as well. It is found that the $\Omega(2012)$ resonance has a sizeable decay rate into the three-body final state $\Xi\pi\bar{K}$. The predicted ratio $R_{\Xi\bar{K}}^{\Xi\pi\bar{K}}=\mathcal{B}[\Omega(2012)\to \Xi^*(1530)\bar{K}\to \Xi\pi\bar{K}]/\mathcal{B}[\Omega(2012)\to \Xi\bar{K}]\simeq 12\%$ is close to the up limit $11\%$ measured by the Belle Collaboration in 2019, however, our predicted ratio is too small to be comparable with the recent data $0.97\pm 0.31$. Furthermore, our results show that the coupled-channel effects on the $\Omega(2012)$ is not large, its components should be dominated by the bare three-quark state, while the proportion of the molecular components is only $\sim 16\%$. To clarify the nature of $\Omega(2012)$, the ratio $R_{\Xi\bar{K}}^{\Xi\pi\bar{K}}$ is expected to be tested by other experiments.