On the Twist 2 and Twist 3 Contributions to the Spin-dependent Electroweak Structure Functions
J. Blümlein, N. Kochelev
TL;DR
The paper computes twist-2 and twist-3 contributions to spin-dependent electroweak structure functions in polarized deep-inelastic scattering with neutral and charged currents using the operator product expansion at leading order in QCD. It shows that the twist-2 sector for the five polarized structure functions is constrained by three linear relations: the Wandzura-Wilczek relation, a Dicus-type relation, and a new integral relation, effectively mapping twist-2 inputs to the full twist-2 content. It also derives novel integral relations linking twist-2 and twist-3 components, including a new relation between g2^III and g3^III, and discusses a twist-3 sum rule. The results illuminate the spin structure of nucleons under weak interactions and provide testable predictions for future polarized DIS experiments.
Abstract
The twist 2 and twist 3 contributions of the polarized deep-inelastic structure functions are calculated both for neutral and charged current interactions using the operator product expansion in lowest order in QCD. The relations between the different structure functions are determined. New integral relations are derived between the twist 2 contributions of the structure functions $g_3(x,Q^2)$ and $g_5(x,Q^2)$ and between combinations of the twist 3 contributions to the structure functions $g_2(x,Q^2)$ and $g_3(x,Q^2)$. The sum rules for polarized deep inelastic scattering are discussed in detail.