Systematic analysis of the D -wave charmonium states with the QCD sum rules

In this paper, we systematically study the 1D charmonium spin-triplet (with the [Formula: see text]) and spin-singlet (with the [Formula: see text]) via the QCD sum rules in comparison with the recent experimental results. The predicted mass [Formula: see text] supports identifying the [Formula: see text] as the [Formula: see text], the value [Formula: see text] is consistent with the reported observation of the [Formula: see text], the prediction [Formula: see text] supports identifying the [Formula: see text] as the [Formula: see text]. Additionally, we estimate the unobserved [Formula: see text] state lies at [Formula: see text], and suggest detection prospects in the future. More experimental data will help us unravel the mass spectrum of the charmonium states near the open-charm thresholds.