Rings and strings: a basis for understanding subleading colour and QCD coherence beyond the two-jet limit

TL;DR

This paper introduces a new kinematic basis derived from the colour flow basis that simplifies soft gluon emission amplitudes, isolates subleading colour effects, and extends angular-ordered parton showers beyond the two-jet limit.

Contribution

It presents a novel set of basis functions that improve the understanding and simulation of QCD coherence effects beyond the two-jet approximation.

Findings

Enhanced statistical convergence of the CVolver code

Isolation of subleading colour contributions

Extension of angular-ordered parton showers

Abstract

Guided by the colour-diagonal structure of collinear singularities, we identify a set of kinematic basis functions that are well suited to the simplification of soft gluon emission amplitudes. In particular, these basis functions, which emerge naturally in the colour flow basis, isolate the subleading colour contributions and improve the statistical convergence of the CVolver amplitude-evolution code. They also allow us to extend current angular-ordered parton showers beyond the azimuthally-averaged, two-jet limit.