The Soft Anomalous Dimension at four loops in the Regge Limit

TL;DR

This paper derives constraints on the four-loop soft anomalous dimension in the Regge limit, advancing understanding of infrared divergences in scattering amplitudes and paving the way for a bootstrap-based determination.

Contribution

It provides new constraints on the four-loop soft anomalous dimension in the Regge limit, facilitating a bootstrap approach for its full determination.

Findings

Derived constraints on the four-loop soft anomalous dimension.

Connected Regge-limit results to the general form of the anomalous dimension.

Enabled a pathway for a bootstrap-based determination.

Abstract

The soft anomalous dimension governs the infrared divergences of scattering amplitudes in general kinematics to all orders in perturbation theory. By comparing the recent Regge-limit results for $2\to2$ scattering (through Next-to-Next-to-Leading Logarithms) in full colour to a general form for the soft anomalous dimension at four loops we derive powerful constraints on its kinematic dependence, opening the way for a bootstrap-based determination.