COLOR TRANSPARENCY AND SCALING PROPERTIES OF NUCLEAR SHADOWING IN DEEP INELASTIC-SCATTERING

We present the perturbative QCD analysis of nuclear shadowing in the deep inelastic scattering at small x in terms of the spatial wave function of qqBAR fluctuations of virtual photons. The wave function formalism makes it quite obvious that shadowing is the scaling, rather than the higher twist, 1/Q2, effect, contrary to a numerous recent claims. We demonstrate explicitly how the scaling shadowing comes from the large, hadronic, size quark-antiquark pairs even in the limit of Q2 --> infinity, and why it should very slowly, is proportional to 1/log(Q2/m2), decrease at very large Q2. We argue in favor of the scaling triple-pomeron contribution to the nuclear shadowing and present predictions for a cross section of diffraction dissociation of virtual photons and for the mass spectrum of diffraction excitation, which can be checked at HERA and Fermilab. We predict strikingly different scaling properties of diffraction dissociation and nuclear shadowing for the longitudinal and transverse photons. Our numerical predictions for shadowing are in good agreement with the recent EMC data.