Semi-Inclusive Deep Inelastic Scattering in Wandzura-Wilczek-type approximation

TL;DR

This paper derives the complete cross-section for unpolarized hadron production in semi-inclusive deep-inelastic scattering within a Wandzura-Wilczek-type approximation, including power-suppressed terms, and provides predictions for experimental testing.

Contribution

It systematically computes twist-2 and twist-3 structure functions and asymmetries under the Wandzura-Wilczek approximation, extending the understanding of TMD theory beyond leading twist.

Findings

Derived complete cross-section including ${ m O}(1/Q^2)$ terms.

Provided predictions for Jefferson Lab, COMPASS, HERMES, and EIC.

Discussed the validity of Wandzura-Wilczek approximations with existing data.

Abstract

We present the complete cross-section for the production of unpolarized hadrons in semi-inclusive deep-inelastic scattering up to power-suppressed ${\cal O}(1/Q^2)$ terms in the Wandzura--Wilczek-type approximation which consists in systematically assuming that $\bar{q}gq$--terms are much smaller than $\bar{q}q$--correlators. We compute all twist-2 and twist-3 structure functions and the corresponding asymmetries, and discuss the applicability of the Wandzura--Wilczek-type approximations on the basis of available data. We make predictions that can be tested by data from Jefferson Lab, COMPASS, HERMES, and the future Electron-Ion Collider. The results of this paper can be readily used for phenomenology and for event generators, and will help to improve our understanding of the TMD theory beyond leading twist.