Tree-level soft emission of a quark pair in association with a gluon
Abstract
We compute the tree-level current for the emission of a soft quark-antiquark pair in association with a gluon. This soft current is the last missing ingredient to understand the infrared singularities that can arise in next-to-next-to-next-to-leading-order (NLO) computations in QCD. Its square allows us to understand for the first time the colour correlations induced by the soft emission of a quark pair and a gluon. We find that there are three types of correlations: Besides dipole-type correlations that have already appeared in soft limits of tree-level amplitudes, we uncover for the first time also a three-parton correlation involving a totally symmetric structure constant. We also study the behaviour of collinear splitting amplitudes in the triple-soft limit, and we derive the corresponding factorisation formula.
Cite
@article{arxiv.2206.01584,
title = {Tree-level soft emission of a quark pair in association with a gluon},
author = {Vittorio Del Duca and Claude Duhr and Rayan Haindl and Zhengwen Liu},
journal= {arXiv preprint arXiv:2206.01584},
year = {2023}
}
Comments
35 pages, 1 figure, 9 ancillary files