The three-loop singlet contribution to the massless axial-vector quark form factor

T Gehrmann,A Primo

doi:10.1016/j.physletb.2021.136223

Abstract

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.

Highlights

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
The infrared singularity structure of the resulting singlet axial-vector form factor is explained from infrared factorization, defining a finite remainder function
The quark form factors describe the coupling of a quark-antiquark pair to an external current, which can be a vector, scalar, axial-vector or pseudo-scalar

Summary

Introduction

The three-loop singlet contribution to the massless axial-vector quark form factor. 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. The infrared singularity structure of the resulting singlet axial-vector form factor is explained from infrared factorization, defining a finite remainder function.

Results

Conclusion