Y(4260) as a mixed charmonium-tetraquark state

TL;DR

This study uses QCD sum rules to analyze the Y(4260) particle as a mixed charmonium-tetraquark state, successfully matching its mass but failing to account for its large decay width, suggesting a different underlying structure.

Contribution

It introduces a mixed charmonium-tetraquark model for Y(4260) and evaluates its mass and decay width using QCD sum rules, highlighting limitations in explaining the decay width.

Findings

Mass matches experimental data at a specific mixing angle.

Decay width calculated is much smaller than observed.

Model cannot fully explain the Y(4260) properties.

Abstract

Using the QCD sum rule approach we study the Y(4260) state assuming that it can be described by a mixed charmonium-tetraquark current with $J^{PC}=1^{--}$ quantum numbers. For the mixing angle around $\theta \approx (53.0\pm 0.5)^{0}$, we obtain a value for the mass which is in good agreement with the experimental mass of the Y(4260). However, for the decay width we find the value $\Ga_Y \approx (1.0\pm 0.2)$ MeV which is not compatible with the experimental value $\Ga \approx (88\pm 23)$ MeV. Therefore, we conclude that, although we can explain the mass of the Y(4260), this state cannot be described as a mixed charmonium-tetraquark state since, with this assumption, we can not explain its decay width.