The generalized vector dominance/colour-dipole picture of deep-inelastic scattering at low x

Abstract

We give a detailed account of the recently formulated generalized vector dominance/colour-dipole picture (GVD/CDP) of deep-inelastic scattering at low $x\cong Q^2/W^2$, including photoproduction. The approach, based on ${\gamma }^{\ast }(q\bar{q})$ transitions, $q\bar{q}$ propagation and diffractive $(q\bar{q})p$ scattering via the generic structure of the two-gluon exchange, provides a unique and quantitatively successful theory for the ${\gamma }^{\ast }p$ total cross section, ${\sigma }_{{\gamma }^{\ast }p}(W^2,Q^2)$, at low $x$. The GVD/CDP is shown to imply the empirical low-$x$ scaling law, ${\sigma }_{{\gamma }^{\ast }p}(W^2,Q^2)={\sigma }_{{\gamma }^{\ast }p}(\eta )$ with $\eta =(Q^2+m_0^2)/{\Lambda }^2(W^2)$, that was established by a model-independent analysis of the experimental data.

Comments: 31 pages, 10 figures, submitted to Eur. Phys. J. C