We compute the three-loop corrections to the quark axial vector form factor in massless QCD, focusing on the pure-singlet contributions where the axial vector current couples to a closed quark loop. Employing the Larin prescription for γ5, we discuss the UV renormalization of the form factor. The infrared singularity structure of the resulting singlet axial-vector form factor is explained from infrared factorization, defining a finite remainder function.
@article{arxiv.2102.12880,
title = {The three-loop singlet contribution to the massless axial-vector quark form factor},
author = {T. Gehrmann and A. Primo},
journal= {arXiv preprint arXiv:2102.12880},
year = {2021}
}