Off-diagonal generalized vector dominance in DIS and QCD

TL;DR

This paper reviews a generalized vector dominance approach to deep inelastic scattering at small x, incorporating QCD-inspired models and analyzing the behavior of cross sections and ratios with respect to Q^2.

Contribution

It introduces a new formulation of GVD that explicitly models the gamma* to qqbar transition and links destructive interference to two-gluon exchange structures.

Findings

Transverse photoabsorption cross section scales as (ln Q^2)/Q^2.

F_2 exhibits logarithmic scaling violation at high Q^2.

Longitudinal-to-transverse ratio decreases as 1/ln Q^2.

Abstract

We review the generalized vector dominance (GVD) approach to DIS at small values of the scaling variable, x. In particular, we concentrate on a recent formulation of GVD that explicitly incorporates the configuration of the gamma^* -> q qbar transition and a QCD-inspired ansatz for the (qqbar)p scattering amplitude. The destructive interference, originally introduced in off-diagonal GVD is traced back to the generic strcuture of two-gluon exchange. Asymptotically, the transverse photoabsorption cross section behaves as (ln Q^2)/Q^2, implying a logarithmic violation of scaling for F_2, while the longitudinal-to-transverse ratio decreases as 1/\ln Q^2. We also briefly comment on vector-meson production.