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

Ri-Qing Qian,Takayuki Matsuki,Xiang Liu,Jun-Zhang Wang

doi:10.1103/physrevd.104.094001

Ri-Qing Qian, Takayuki Matsuki + Show 2 more

Open Access

https://doi.org/10.1103/physrevd.104.094001

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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.

Highlights

As the important member of hadron spectroscopy, charmonium family has attracted extensive attention from both theorist and experimentalist since the first charmonium J=ψ was discovered in 1974 [1,2]
Since charmonium is a typical mesonic system composed of charm and anticharm quarks, charmonium corresponding to lowenergy particle physics can be treated as ideal platform to help us to deepen our understanding of nonperturbative behavior of quantum chromodynamics (QCD), which is full of challenge and opportunity
In our former work [22], we found that the Yð4660Þ and Yð4630Þ may have close relation to two charmonium states ψ and ψ 060S−5D, which are the mixture of ψð6SÞ and ψð5DÞ

Summary

INTRODUCTION

As the important member of hadron spectroscopy, charmonium family has attracted extensive attention from both theorist and experimentalist since the first charmonium J=ψ was discovered in 1974 [1,2]. We apply the hadronic loop mechanism, which has been widely applied to the explorations of hidden-charm and hidden-bottom decays of charmonium and bottomonium [28,29,30,31,32,33,34,35,36,37,38,39,40,41], to study the ψ → ΛcΛc decays. The decay of higher charmonia to ΛcΛc needs one more light quark-antiquark pair creations than the decay channel composed of charmed meson pairs. The ψ decays into their dominant final states DððÃsÞÞDððÃsÞÞ, and the DððÃsÞÞDððÃsÞÞ is transformed to final states ΛcΛc via exchanging a baryon This is the hadronic loop mechanism existing in the decay process ψ → ΛcΛc. Are evaluated with the help of LoopTools package [44,45], by which both the real and imaginary parts are considered in our calculation

TWO APPLICATIONS

Reproducing branching ratios of ψ

ΛcDðsÃÞΛ

DISCUSSION AND CONCLUSION