The Challenge of Small x

TL;DR

This paper reviews the theoretical understanding of inclusive cross sections at small x and large Q^2, examining the consistency between Altarelli-Parisi evolution, BFKL equation, and Regge theory.

Contribution

It critically assesses the mutual consistency of different theoretical frameworks describing small x physics in high-energy scattering.

Findings

Identifies areas of agreement and discrepancy among the theories.

Highlights challenges in unifying the approaches.

Provides insights into the behavior of cross sections at small x.

Abstract

We review the current understanding of the behaviour of inclusive cross sections at small x and large Q^2 in terms of Altarelli-Parisi evolution, the BFKL equation, and Regge theory, asking in particular to what extent they are mutually consistent.