NLO calculations at small x

¹ Theoretical Physics Division, National Centre for Nuclear Research, Pasteura 7, Warsaw 02-093, Poland
² Department of Physics, University of Jyväskylä, P.O. Box 35, 40014 University of Jyväskylä, Finland
³ Helsinki Institute of Physics, P.O. Box 64, 00014 University of Helsinki, Finland
⁴ Department of Physics and Astronomy, University of California, Los Angeles, CA 90095, USA
⁵ Mani L. Bhaumik Institute for Theoretical Physics, University of California, Los Angeles, CA 90095, USA

^* e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

Published online: 17 April 2026

Abstract

We discuss recent progress in next-to-leading order calculations for dilute-dense-processes in the small-x gluon saturation regime, especially for Deep Inelastic Scattering observables. A systematical formalism for such observables is provided by a combination of light cone perturbation theory for the dilute probe, combined with a Color Glass Condensate picture for eikonal scattering off the dense gluonic target. In particular we focus here on the recent calculation of the diffractive DIS structure function, which is expected to be more sensitive to gluon saturation than inclusive DIS observables.