Deep inelastic Scattering, QCD, and generalised vector dominance

TL;DR

This paper develops a generalized vector dominance model for low-x deep-inelastic scattering, incorporating QCD effects and explaining the behavior of the photoabsorption cross section and structure functions.

Contribution

It introduces a formulation of GVD that explicitly includes the gamma* to q qbar transition and a QCD-inspired amplitude, linking interference effects to two-gluon exchange and color transparency.

Findings

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

Logarithmic violation of scaling observed in F_2.

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

Abstract

We provide a formulation of generalised vector dominance (GVD) for low-x deep-inelastic scattering that explicitly incorporates the ${\gamma}^{\ast} \to q{\bar q}$ transition and a QCD-inspired ansatz for the $(q{\bar q})p$ forward-scattering amplitude. The destructive interference originally introduced in off-diagonal GVD is recovered in the present formulation and traced back to the generic structure of two-gluon-exchange as incorporated into the notion of colour transparency. 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.