J/ψ-Photoproduction and the gluon structure of the nucleon Original Research Article

Using QCD sum rule method based on the operator product expansion, we calculate the J/ψ photoproduction cross section in terms of the gluon distribution function of the nucleon. Comparing the results with the data, we show that experimental behaviour of the cross section correctly reflects the x-dependence of the gluon distribution obtained from deep inelastic scattering.