We calculate the cross section of the exclusive process e++e−→J/ψ+ηc at the leading order approximation within the QCD light-cone sum rules (LCSR) approach. It is found that the form factor FVP(V=J/ψ,P=ηc) depends mainly on the behavior of the twist-2 distribution amplitude of the ηc-meson at the scale of this process. Thus in order to obtain a reliable estimation of the cross section, it is important to have a realistic distribution amplitude of the ηc meson, and to deal with the evolution of the distribution amplitude to the effective energy scale of the process. Our results show that one can obtain a compatible prediction with the Belle and BarBar experimental data.
@article{arxiv.0911.0963,
title = {The cross section of the process $e^{+}+e^{-}\to J/\psi+\eta_c$ within the QCD light-cone sum rules},
author = {Yan-Jun Sun and Xing-Gang Wu and Fen Zuo and Tao Huang},
journal= {arXiv preprint arXiv:0911.0963},
year = {2011}
}