Perturbative QCD analysis of exclusive J/ψ+η_c production in e^+e^- annihilation

Abstract

We analyze the exclusive charmonium $J/ψ+η_c$ pair production in $e^+e^-$ annihilation using the nonfactorized perturbative QCD and the light-front quark model(LFQM) that goes beyond the peaking approximation. We effectively include all orders of higher twist terms in the leading order of QCD coupling constant and compare our nonfactorized analysis with the usual factorized analysis in the calculation of the cross section. We also calculate the quark distribution amplitudes, the Gegenbauer moments, and the decay constants for $J/ψ$ and $η_c$ mesons using our LFQM. Our nonfactorized result enhances the NRQCD result by a factor of $3\sim4$ at $\sqrt{s}=10.6$ GeV.

17 pages, 6figures; added 2 more figures; version to appear in Physical Review D