Charmonium decays into ΛcΛ¯c pair governed by the hadronic loop mechanism

In this work, we investigate the open-charm decay process $\\ensuremath{\\psi}\\ensuremath{\\rightarrow}{\\mathrm{\\ensuremath{\\Lambda}}}_{c}{\\overline{\\mathrm{\\ensuremath{\\Lambda}}}}_{c}$ via the hadronic loop mechanism for vector charmonia above ${\\mathrm{\\ensuremath{\\Lambda}}}_{c}{\\overline{\\mathrm{\\ensuremath{\\Lambda}}}}_{c}$ threshold. The branching ratios of these vector charmonium states to ${\\mathrm{\\ensuremath{\\Lambda}}}_{c}{\\overline{\\mathrm{\\ensuremath{\\Lambda}}}}_{c}$ are estimated. The charmonium explanation of the $Y(4630)$ observed in ${e}^{+}{e}^{\\ensuremath{-}}\\ensuremath{\\rightarrow}{\\mathrm{\\ensuremath{\\Lambda}}}_{c}{\\overline{\\mathrm{\\ensuremath{\\Lambda}}}}_{c}$ is tested. Furthermore, for the predicted higher vector charmonia above 4.7 GeV, the branching ratios $\\mathcal{B}[\\ensuremath{\\psi}(nS)\\ensuremath{\\rightarrow}{\\mathrm{\\ensuremath{\\Lambda}}}_{c}{\\overline{\\mathrm{\\ensuremath{\\Lambda}}}}_{c}]$ with $n=7$, 8, 9 are found to be of the order of magnitude of ${10}^{\\ensuremath{-}4}\\ensuremath{-}{10}^{\\ensuremath{-}3}$ while $\\mathcal{B}[\\ensuremath{\\psi}(mD)\\ensuremath{\\rightarrow}{\\mathrm{\\ensuremath{\\Lambda}}}_{c}{\\overline{\\mathrm{\\ensuremath{\\Lambda}}}}_{c}]$ with $m=6$, 7, 8 are of the order of magnitude of ${10}^{\\ensuremath{-}3}\\ensuremath{-}{10}^{\\ensuremath{-}2}$. The experimental signals of these missing charmonium states are discussed. The search for them may be an interesting topic in the future BESIII and Belle II experiments.