Low-x scaling in $γ^*p$ total cross sections

Abstract

We show that the experimental data for the total virtual-photon proton cross section, σ_{γ^*p} (W^2, Q^2), for x_{bj} \lsim 0.1 lie on a universal curve, when plotted against η= (Q^2 + m^2_0)/ Λ^2(W^2), where Λ^2 (W^2) = C_1 (W^2+W^2_0)^{C_2} is determined by the parameters m^2_0, C_1, C_2 and W^2_0. The observed scaling law follows from the generalized-vector-dominance/color-dipole picture of low-x deep inelastic scattering.