Light-quark components analysis and the nature of the $Y(4260)$

TL;DR

This study investigates the internal structure of the $Y(4260)$ resonance, revealing it contains significant light-quark components and is neither a hybrid nor a conventional charmonium, based on dispersion theory analysis of decay processes.

Contribution

It introduces a model-independent dispersion theory approach to analyze the light-quark content of $Y(4260)$, challenging previous interpretations of its nature.

Findings

$Y(4260)$ has a large light-quark component.

It is not a hybrid or conventional charmonium.

It does not behave like a pure $ar D D_1$ molecular state.

Abstract

We study the processes $e^+ e^- \to Y(4260) \to J/\psi \pi\pi(K\bar{K})$. The strong final-state interactions, especially the coupled-channel ($\pi\pi$ and $K\bar{K}$) final-state interaction in the $S$-wave are taken into account in a model-independent way using dispersion theory. It is found that the light-quark SU(3) octet state plays a significant role in these transitions, implying that the $Y(4260)$ contains a large light-quark component. Our findings suggest that the $Y(4260)$ is neither a hybrid nor a conventional charmonium state. Furthermore, through an analysis of the ratio of the light-quark SU(3) octet and singlet components, we show that the $Y(4260)$ does not behave like a pure $\bar D D_1$ hadronic molecule as well.