An Introduction to Spin Dependent Deep Inelastic Scattering

TL;DR

This paper provides a theoretical overview of spin-dependent deep inelastic scattering within QCD, deriving key relations and sum rules without relying on phenomenological models, focusing on spin 1/2 targets.

Contribution

It offers a QCD-based derivation of fundamental relations and sum rules in spin-dependent deep inelastic scattering, emphasizing a field-theoretic approach.

Findings

Derivation of the Callan-Gross relation from QCD

Analysis of the longitudinal structure function $F_L$

Discussion of the Bjorken and Ellis-Jaffe sum rules

Abstract

The main focus of these lectures is on those aspects of deep inelastic scattering that can be derived directly from QCD using quantum field theory, without recourse to phenomenological models. The emphasis is on spin dependent scattering, but the theory of spin averaged scattering is also discussed. A detailed analysis is given for the case of spin 1/2 targets, with a brief discussion of higher spin targets at the end. The QCD derivation of the Callan-Gross relation, the longitudinal structure function $F_L$, and the Bjorken and Ellis-Jaffe sum rules is presented. I also discuss the Wilczek-Wandzura contribution to $g_2$, and why the Gottfried sum rule does not hold in QCD.