NLO QCD corrections to exclusive electroproduction of quarkonium

Abstract

The process of exclusive electroproduction of vector quarkonium (EEQ), $e p\to epV$, is per se an interesting topic in studies of quarkonium production mechanism, QCD description of diffractive interaction and nucleon structure. We investigate this process in the framework of nonrelativistic QCD and QCD collinear factorization at the next-to-leading order QCD accuracy. The perturbative convergence behavior is discussed in a large range of photon virtuality $Q^2$. The $J/\psi$ large-$Q^2$ electroproduction data at HERA can be well explained, and the $\Upsilon$ differential production rate is predicted. The uncertainties in theoretical predictions with radiative corrections are greatly reduced. Notice the EEQ process is extremely sensitive to the gluon distribution in nucleon, the generalized parton distribution, our results will constraint the gluon density with high precision while confronting to the future experimental data. For the sake of comparing convenience, the analytic expressions are provided.