Space-time structure of deep-inelastic lepton-hadron scattering

We discuss the space-time structure of deep-inelastic scattering in the target rest frame. At small Bjorken $x$, the process is dominated by quark pair production, and the "Ioffe time" between the production of the pair and its interaction in the target is long. We compute the leading logarithmic corrections to the parton model predictions for the virtual photoabsorption cross section, and analyze the transverse size of the pair and the Ioffe time as a function of the dynamical variables of the pair constituents. Both the transverse size and the Ioffe time depend significantly on the polarization (longitudinal or transverse) of the virtual photon. Hence one may expect that nuclear scattering corrections, including shadowing, may also be polarization dependent.