Eur. Phys. J. C (2010) 67: 117-123
https://doi.org/10.1140/epjc/s10052-010-1280-z

Regular Article - Theoretical Physics

The cross section of the process e ⁺+e ⁻→J/ψ+η _c within the QCD light-cone sum rules

¹ Department of Modern Physics, University of Science and Technology of China, Hefei, 230026, P.R. China
² Institute of High Energy Physics and Theoretical Physics Enter for Science Facilities, Chinese Academy of Sciences, Beijing, 100049, P.R. China
³ Department of Physics, Chongqing University, Chongqing, 400044, P.R. China
⁴ Key Laboratory of Frontiers in Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing, 100190, P.R. China

^* e-mail: sunyj@ihep.ac.cn

Received: 11 November 2009
Revised: 15 January 2010
Published online: 9 March 2010

Abstract

We calculate the cross section of the exclusive process e ⁺+e ⁻→J/ψ+η _c at the leading order approximation within the QCD light-cone sum rules approach. It is found that the form factor F _VP(V=J/ψ,P=η _c ) depends mainly on the behavior of the twist-2 distribution amplitude of the η _c 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 η _c 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 BaBar experimental data.