Cwebs in multiparton scattering amplitude: Structures at four loops

Abstract

Soft function exponentiates in terms of the soft anomalous dimension ΓS; the Feynman diagrams contributing to it are called Cwebs. The colour and kinematics of a Cweb mix via a web mixing matrix – calculation of web mixing matrices at higher loop orders is a nontrivial task using replica trick. Here I discuss a recent development of an efficient algorithm to find the Cwebs that are present at any loop order, and the result of mixing matrices, and exponentiated colour factors associated with Boomerang Cweb at four loops connecting three and four Wilson lines.