Nuclear shadowing and the optics of hadronic fluctuations

A coordinate-space description of shadowing in deep-inelastic lepton-nucleu s scattering is presented. The picture in the laboratory frame is that of q uark-gluon fluctuations of the high-energy virtual photon, propagating cohe rently over large light-cone distances in the nuclear medium. We discuss th e detailed dependence of the coherence effects on the invariant mass of the fluctuation. We comment on the issue of possible saturation in the shadowi ng effects at very small Bjorken-x. (C) 2001 Elsevier Science B.V. All righ ts reserved.