QCD-Instantons and Saturation at Small x

Abstract

We briefly report on the contribution of QCD-instantons to the phenomenon of saturation in deep-inelastic scattering (DIS) at small Bjorken-x. The explicitly known instanton gauge field serves as a concrete realization of an underlying non-perturbative saturation mechanism associated with strong classical fields. Two independent strategies were pursued, with consistent results: On the one hand, an approach starting from instanton-perturbation theory was considered and on the other hand, the scattering of a Wilson loop in an instanton gauge field background. In both cases, the conspicuous, intrinsic instanton size scale <rho> ~ 0.5 fm, as known from the lattice, turns out to determine the saturation scale.