Analysis of the strong decays of the $Y(4660)$ in tetraquark scenario via the QCD sum rules

TL;DR

This work addresses the nature of the vector charmonium-like state Y(4660) by testing four vector tetraquark currents with $J^{PC}=1^{--}$ using three-point QCD sum rules. By computing hadronic coupling constants up to dimension-5 condensates and applying quark-hadron duality, it derives partial and total decay widths for the candidate configurations. The key finding is that the configuration Y involving a $[sc]S[ar{s}ar{c}]_{ ilde{V}}$ − $[sc]_{ ilde{V}}[ar{s}ar{c}]_{S}$ type yields a total width $\\Gamma \\approx 61.5 \,\pm \,7.3$ MeV, consistent with the experimental width of the Y(4660) from Belle and the PDG average, supporting its interpretation as a $[sc][\bar{s}\bar{c}]$ tetraquark. The other configurations predict widths that are too large or too small, disfavoring those assignments. These results provide a quantitative link between the internal tetraquark structure and observed decay patterns, offering guidance for future experimental tests.

Abstract

Motivated by the enigmatic vector charmonium-like states, we investigate the strong decay behaviors of four kinds of tetraquark states, which are possible candidates for the $Y(4660)$, within the framework of three-point QCD sum rules based on rigorous quark-hadron duality. We take into account the vacuum condensates up to dimension 5 in the QCD side, and obtain the hadronic coupling constants therefore the partial decay widths of those states. The predicted width $61.5\pm7.3\,\rm{MeV}$ is in excellent agreement with the experimental data for the $Y(4660)$, which supports its interpretation as a $[sc][\bar{s}\bar{c}]$ tetraquark state with the $J^{PC}=1^{--}$.

Figures (1)

• Figure 1: The hadron-coupling constants with variations of the Borel parameters, where the $A$ and $B$ denote the hadronic coupling constants $G_{\bar{D}_{s0}D_s^* S\widetilde{V}}$ and $G_{\bar{D}_{s1}D_s S\widetilde{V}}$, respectively.