The Spectra of $p\bar\Lambda$ and $p\bar\Sigma$ Hexaquark States

TL;DR

This study uses QCD sum rules to explore possible hexaquark molecular states in the $par{\Lambda}$ and $par{\Sigma}$ systems, finding potential states near observed resonances but not supporting the $X(2085)$ as a molecular state.

Contribution

It provides a detailed QCD sum rule analysis of baryon-antibaryon hexaquark states, considering non-perturbative effects up to dimension 13, and predicts possible molecular states with specific quantum numbers.

Findings

Six possible molecular states identified with $J^{P}=0^{-}, 0^{+}, 1^{-}$.

Results do not support $X(2085)$ as a $par{\Lambda}$ or $par{\Sigma}$ molecular state.

Masses of $J^{P} = 1^{-}$ states are near the observed $X(2075)$, suggesting further investigation.

Abstract

Motivated by the observation of the $J^P = 1^+$ resonance $X(2085)$ in the $p\bar{\Lambda}$ system by the BESIII collaboration, we studied the molecular states of hexaquarks $p\bar{\Lambda}$ and $p\bar{\Sigma}$ with baryon-antibaryon structures within the framework of the QCD sum rules. Non-perturbative contributions up to dimension 13 were considered in our analysis. The results indicate the existence of six possible molecular states $p\bar{\Lambda}$ and $p\bar{\Sigma}$, with quantum numbers $J^{P}=0^{-}, 0^{+}, 1^{-}$. Consequently, the current sum rule results do not support the interpretation of $X(2085)$ as a $p\bar{\Lambda}$ or $p\bar{\Sigma}$ molecular state. On the other hand, we find that the masses of the proposed $p\bar{\Lambda}$ and $p\bar{\Sigma}$ structures with $J^{P} = 1^{-}$ are in the vicinity of observed $X(2075)$, which implies that the nature of this state needs more invistigations. Moreover, the possible decay modes of the concerned hexaquark states are analyzed.