$Y(4260)$ as four-quark state

TL;DR

This paper models the $Y(4260)$ resonance as a four-quark state using a covariant confining quark model, comparing molecular and tetraquark interpretations to explain its decay modes and widths.

Contribution

It introduces a covariant confining quark model analysis of $Y(4260)$ as a four-quark state, comparing molecular and tetraquark currents for the first time.

Findings

The decay mode $Y o Z_c + \pi$ is enhanced in both models.

The decay width in the molecular model is likely too large.

The tetraquark model yields a more reasonable decay width.

Abstract

We treat the $Y(4260)$ resonance as a four-quark state in the framework of the covariant confining quark model. We study two choices of the interpolating current, either the molecular-type current which effectively corresponds to the product of $D$ and $\bar D_1$ quark currents or tetraquark one. In both cases we calculate the widths of decays $Y(4260)\to Z_c(3900)+\pi$ and $Y(4260)\to D^{(\ast)}+\bar D^{(\ast)}$. It is found that in both approches the mode $Y\to Z^+_c + \pi^-$ is enhanced compared with the open charm modes. However the absolute value of the $Y\to Z^+_c + \pi^-$ decay width obtained in molecular picture is arguably too large. On the other hand the value obtained in tetraquark picture is reasonable.