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

TL;DR

This paper studies the decay of vector charmonia into Lambda_c pairs via hadronic loops, estimating branching ratios and testing the charmonium explanation of the Y(4630), with implications for future experiments.

Contribution

It provides the first estimates of branching ratios for higher vector charmonia decaying into Lambda_c pairs using the hadronic loop mechanism.

Findings

Branching ratios for higher vector charmonia are around 10^{-4} to 10^{-3}.

Predicted decay rates for certain charmonia suggest potential signals in future experiments.

The study supports the charmonium interpretation of the Y(4630) resonance.

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.