Local analytic sector subtraction for initial- and final-state radiation at NLO in massless QCD

TL;DR

This paper introduces a local analytic sector subtraction method for NLO QCD calculations involving initial- and final-state radiation, improving numerical stability and paving the way for NNLO applications in collider physics.

Contribution

The paper presents a detailed local analytic sector subtraction technique for NLO QCD with initial and final-state massless particles, including an optimization for numerical stability.

Findings

Validated numerically for collider-relevant processes

Improves numerical stability without added analytic complexity

Prepares groundwork for NNLO initial-state radiation calculations

Abstract

Within the framework of local analytic sector subtraction, we present the subtraction of next-to-leading-order QCD singularities for processes featuring massless coloured particles in the initial as well as in the final state. The features of the method are explained in detail, including the introduction of an optimisation procedure aiming at improving numerical stability at the cost of no extra analytic complexity. A numerical validation is provided for a variety of processes relevant to lepton as well as hadron colliders. This work constitutes a relevant step in view of the application of our subtraction method to processes involving initial-state radiation at next-to-next-to-leading order in QCD.