Transverse momentum dependent factorization for SIDIS at next-to-leading power

TL;DR

This paper derives the complete next-to-leading power TMD factorization formula for SIDIS, including one-loop perturbative elements and the evolution of twist-three TMD fragmentation functions, refining previous results.

Contribution

It provides the full next-to-leading power SIDIS structure functions with one-loop accuracy, addressing previous discrepancies and including twist-three TMD fragmentation functions.

Findings

Differences with earlier derivations due to quark-gluon interference kinematics

Complete one-loop coefficient functions and evolution kernels for SIDIS

Definition and evolution of twist-three TMD fragmentation functions

Abstract

The semi-inclusive deep-inelastic scattering (SIDIS) is the golden process for investigating the nucleon's transverse momentum-dependent (TMD) structure. We present the complete expression for SIDIS structure functions in the TMD factorization formalism at the next-to-leading power. All perturbative elements of the factorization theorem -- coefficient functions and evolution kernels -- are presented at one-loop accuracy. We found several differences with earlier derivations, which are due to accounting for nontrivial kinematics of the quark-gluon interference terms. As a side result, we present the definition and evolution of twist-three TMD fragmentation functions, including the leading-order evolution kernel.