PUB - Publikationen an der Universität Bielefeld

The scaling in sigma(gamma*p) (W-2, Q(2)) cross sections (for Q(2)/W-2 much less than 1) in terms of the scaling variable eta = (Q(2) + m(0)(2)) /Lambda(2) (W-2) is interpreted in the Generalized Vector Dominance/Color-Dipole Picture (GVD/CDP). The quantity Lambda(2) (W-2) is identified as the average gluon transverse momentum absorbed by the q (q) over bar state, <(l) over right arrow (2)(perpendicular to)> = (1/6)Lambda(2). At any Q(2), for W-2 --> infinity, the cross sections for virtual and real photons become universal, sigma(gamma*p) (W-2, Q(2)) / sigma(gammap) (W-2) --> 1. The gluon density corresponding to the color-dipole cross section in the appropriate limit is found to be consistent with the results from QCD fits.