A general algorithm to build real-radiation antenna functions for higher-order calculations

TL;DR

This paper introduces a universal algorithm for constructing antenna functions used in higher-order QCD calculations, simplifying the process of NNLO subtraction in particle physics.

Contribution

The authors develop a general algorithm to generate antenna functions for any number of real emissions directly from unresolved limits, improving upon previous methods.

Findings

Successfully built all single- and double-real QCD antenna functions.

Compared new antenna functions with previous ones, confirming consistency.

Enhanced applicability of antenna functions to NNLO subtraction terms.

Abstract

The antenna subtraction method has been successfully applied to a wide range of processes relevant for the Large Hadron Collider at next-to-next-to-leading order in $\alpha_s$ (NNLO). We propose an algorithm for building antenna functions for any number of real emissions from an identified pair of hard radiator partons directly from a specified list of unresolved limits. We use the algorithm to explicitly build all single- and double-real QCD antenna functions and compare them to the previous antenna functions, which were extracted from matrix elements. The improved antenna functions should be more easily applicable to NNLO subtraction terms. Finally, we match the integration of the antenna functions over the final-final unresolved phase space to the previous incarnation, serving as an independent check on our results.