Deciphering Colour Building Blocks of Massive Multiparton Amplitudes at 4-loops and beyond

TL;DR

This paper advances the understanding of multiparton amplitudes by establishing a correspondence between boomerang webs and non-boomerang Cwebs, enabling all-order construction of their diagonal blocks and mixing matrices in perturbation theory.

Contribution

It introduces a novel correspondence between boomerang webs and non-boomerang Cwebs, facilitating all-order calculations of their structures in multiparton amplitudes.

Findings

Established correspondence between boomerang webs and non-boomerang Cwebs.

Constructed diagonal blocks of four classes of Cwebs to all orders.

Fully constructed the mixing matrix of a specific Cweb to all orders.

Abstract

The soft function in non-abelian gauge theories exponentiate, and their logarithms can be organised in terms of the collections of Feynman diagrams called Cwebs. The colour factors that appear in the logarithm are controlled by the web mixing matrices. Direct construction of the diagonal blocks of Cwebs using the new concepts of Normal ordering, basis Cweb and Fused-Web was recently carried out in~\cite{Agarwal:2022wyk}. In this article we establish correspondence between the boomerang webs introduced in ~\cite{Gardi:2021gzz} and non-boomerang Cwebs. We use this correspondence together with Uniqueness theorem and Fused web formalism introduced in ~\cite{Agarwal:2022wyk} to obtain the diagonal blocks of four general classes of Cwebs to all orders in perturbation theory which also cover all the four loop Boomerang Cwebs connecting four Wilson lines. We also fully construct the mixing matrix of a special Cweb to all orders in perturbation theory.