A KLT-like construction for multi-Regge amplitudes

TL;DR

This paper develops a KLT-like decomposition method for multi-Regge limit amplitudes in N=4 super-Yang-Mills theory, revealing structural similarities to string theory constructions but with added complexities for higher points.

Contribution

It introduces a novel decomposition of multi-Regge amplitudes into products of multi- and single-valued components, extending KLT-like ideas beyond string theory.

Findings

Decomposition of six-point remainder function into multi- and single-valued parts.

Structural similarity to KLT construction in string theory.

Complexities increase with more than six external legs.

Abstract

Inspired by the calculational steps originally performed by Kawai, Lewellen and Tye, we decompose scattering amplitudes with single-valued coefficients obtained in the multi-Regge-limit of N=4 super-Yang-Mills theory into products of scattering amplitudes with multi-valued coefficients. We consider the simplest non-trivial situation: the six-point remainder function complementing the Bern-Dixon-Smirnov ansatz for multi-loop amplitudes. Utilizing inverse Mellin transformations, all single-valued amplitude components can indeed be decomposed into multi-valued amplitude components. Although the final expression is very similar in structure to the Kawai-Lewellen-Tye construction, moving away from the highly symmetric string scenario comes with several imponderabilities, some of which become more pronounced when considering more than six external legs in the remainder function.