2025/09/22 by Qian, Ri-Qing, Liu, Xiang · 1 citation
#FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph)
paper · doi:10.48550/arxiv.2509.17679
The recent observation of multiple near-threshold structures in e+e- annihilation-including ψ(3770), G(3900), R(3760), R(3780), and R(3810)-reveals limitations in existing models of charmonium and exotic hadrons. In this paper, we propose a unified coupled-channel description that simultaneously incorporates all five near-threshold structures using parameters constrained by hadron spectroscopy. Our model accurately reproduces the line shapes in both DD and nonopen-charm hadron (nOCH) channels, resolves the asymmetric profile of ψ(3770), and produces the G(3900) bump. We identify the R(3780) as the dominant manifestation of ψ(3770), attribute R(3760) to DD → nOCH rescattering and suggest that R(3810) arises from coupling between the ψ(1D) state and the hcππ channel. The significant non-DD decay of ψ(3770) is explained by its near-threshold position. This analysis provides a coherent, unquenched framework centered on a charmonium ψ(1D) core for near-threshold phenomena and offers a predictive approach extendable to bottomonium systems and future data from Belle II.