Eur. Phys. J. C (2004) 34: 297-316
https://doi.org/10.1140/epjc/s2004-01712-x

theoretical physics

Exclusive photoproduction of a heavy vector meson in QCD

¹ Institute of Mathematics, 630090, Novosibirsk, Russia
² Institut für Theoretische Physik, Universität Regensburg, Regensburg, Germany
³ Soltan Institute for Nuclear Studies, Hoza 69, 00-681, Warsaw, Poland
⁴ Department of Theoretical Physics, St. Petersburg State University, 198904, St. Petersburg, Russia

Abstract

The process of exclusive heavy vector meson photoproduction, , is studied in the framework of QCD factorization. The mass of the produced meson, or , provides a hard scale for the process. We demonstrate that, in the heavy quark limit and at the one-loop order in perturbation theory, the amplitude factorizes in a convolution of a perturbatively calculable hard-scattering amplitude with the generalized parton densities and the non-relativistic QCD matrix element . We evaluate the hard-scattering amplitude at one-loop order and compare the data with theoretical predictions using an available model for generalized parton distributions.