Searching for the two poles of the $\Xi(1820)$ in the $\psi(3686) \to \bar{\Xi}^+ \bar{K}^0 \Sigma^{*-}(\pi^- \Lambda)$ decay

TL;DR

This paper proposes a decay process to identify two distinct $ ext{Xi}(1820)$ states, one narrow at 1824 MeV and another broader at 1875 MeV, using the $ ext{psi}(3686)$ decay at BESIII.

Contribution

It introduces a new reaction channel to distinguish two $ ext{Xi}(1820)$ states based on their mass and width differences, enhancing detection prospects.

Findings

Higher mass resonance effect is magnified over phase space.

Estimated production rate exceeds previous related reactions.

Proposed method is suitable for BESIII to observe both states.

Abstract

We propose the reaction $\psi(3686) \to \bar{\Xi}^+ \bar{K}^0 \Sigma^{*-}$, with the $\Sigma^{*-}$ decaying to $\pi^- \Lambda$ in order to show evidence for the existence of two $\Xi(1820)$ states, one around $1824$ MeV and narrow, and another one around $1875$ MeV and wide. The phase space for $\bar{K}^0 \Sigma^{*-}$ production reduces the effect of the lower mass resonance, magnifying the effect of the higher mass resonance that shows clearly over the phase space. The estimated rate of the production is bigger than the one of the $\psi(3686) \to \bar{\Xi}^+ K^- \Lambda$ reaction, where a clear peak for $\Xi(1820)$ was observed by the BESIII collaboration, what makes the Beijing facility ideal to carry out the reaction proposed.