Exclusive production of light vector mesons at next-to-leading order in the dipole picture

Abstract

Exclusive production of light vector mesons in deep inelastic scattering is calculated at next-to-leading order in the dipole picture in the limit of high photon virtuality. The resulting expression is free of any divergences and suitable for numerical evaluations. The higher-order corrections are found to be numerically important, but they can be mostly captured by the nonperturbative fit parameters describing the initial condition for the small-$x$ evolution of the dipole scattering amplitude. The vector meson production cross section is shown to depend only weakly on the meson distribution amplitude and the factorization scale. We also present phenomenological comparisons of our result to the existing exclusive $\varphi$ and $\rho$ production data from HERA and find an excellent agreement at high virtualities.

Comments: 25 pages, 25 figures; v2: Corrected typos, modified discussion at the end of Sec. IV