Conformal Invariance of the Subleading Soft Theorem in Gauge Theory

TL;DR

This paper demonstrates that the subleading soft factor in massless gauge theory is uniquely determined by conformal symmetry at tree level in four dimensions.

Contribution

It establishes a direct link between conformal invariance and the subleading soft theorem in gauge theories, providing a symmetry-based derivation.

Findings

Subleading soft factor is uniquely fixed by conformal symmetry.

Conformal symmetry constrains gauge theory amplitudes at tree level.

The result applies specifically to four-dimensional massless gauge theories.

Abstract

In this note, I show that the recently proposed subleading soft factor in massless gauge theory uniquely follows from conformal symmetry of tree-level gauge theory amplitudes in four dimensions.