Charmonium decays into ${\Lambda }_c{\bar{\Lambda }}_c$ pair governed by the hadronic loop mechanism

Abstract

In this work, we investigate the open-charm decay process $\psi \to {\Lambda }_c{\bar{\Lambda }}_c$ via the hadronic loop mechanism for vector charmonia above ${\Lambda }_c{\bar{\Lambda }}_c$ threshold. The branching ratios of these vector charmonium states to ${\Lambda }_c{\bar{\Lambda }}_c$ are estimated. The charmonium explanation of the $Y(4630)$ observed in $e^{+}{e}^{-}\to {\Lambda }_c{\bar{\Lambda }}_c$ is tested. Furthermore, for the predicted higher vector charmonia above 4.7 GeV, the branching ratios $\mathcal{B}[\psi (nS)\to {\Lambda }_c{\bar{\Lambda }}_c]$ with $n=7,8,9$ are found to be of the order of magnitude of $10^{-4}-10^{-3}$ while $\mathcal{B}[\psi (mD)\to {\Lambda }_c{\bar{\Lambda }}_c]$ with $m=6,7,8$ are of the order of magnitude of $10^{-3}-10^{-2}$. 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.

Comments: 8 pages, 6 figures and 4 tables. Accepted by Phys. Rev. D