Next-to-leading-order QCD correction to e+e-→J/ψ+ηc at s=10.6GeV

One of the most challenging open problems in heavy quarkonium physics is the double charm production in e+e- annihilation at B factories. The measured cross section of e+e-→J/ψ+ηc is much larger than leading order (LO) theoretical predictions. With the nonrelativistic QCD factorization formalism, we calculate the next-to-leading order (NLO) QCD correction to this process. Taking all one-loop self-energy, triangle, box, and pentagon diagrams into account, and factoring the Coulomb-singular term into the cc̄ bound state wave function, we get an ultraviolet and infrared finite correction to the cross section of e+e-→J/ψ+ηc at s=10.6GeV. We find that the NLO QCD correction can substantially enhance the cross section with a K factor (the ratio of NLO to LO) of about 1.8-2.1; hence, it greatly reduces the large discrepancy between theory and experiment.