(J/ψ,J/ψ), and (ηc,ηc) production through two intermediate photons in electron-positron annihilation at B-factories

Abstract

We study the processes, e−e+→γ⁎γ⁎→J/ψ+J/ψ, and e−e+→γ⁎γ⁎→ηc+ηc at s=10.6 GeV in the framework of 4×4 Bethe-Salpeter equation. For J/ψ+J/ψ production, the dominant contribution is through fragmentation process, while for ηc+ηc production, the quark rearrangement diagrams contribute. Our results of cross section for J/ψ+J/ψ and ψ(2S)+ψ(2S) are compatible with the experimental upper limits set by Belle Collaboration, while in the absence of experimental data for ηc(1S)+ηc(1S), and ηc(2S)+ηc(2S) production, we have given theoretical prediction of their cross sections, and compared with NRQCD prediction.