Cancellation of IR singularities at NLO and NNLO within Local analytic sector subtraction

by Gloria Bertolotti (University of Turin)

Monday 7 Nov 2022, 11:30 → 12:30 Europe/Zurich

Aula Caldirola (Università degli Studi di Milano)

In this talk, I report the latest results obtained within the framework of Local analytic sector subtraction, a scheme aimed at tackling the problem of infrared (IR) singularities in order to perform multi-parton high-precision QCD calculations. In detail, I present the next-to-next-to-leading-order (NNLO) subtraction formula for local cancellation of IR divergences for massless QCD final states, applying to generic IR-safe observables. I will explicitly introduce the features of the method and investigate a comprehensive treatment of singularities, ultimately necessary to ensure the locality of the subtraction. After performing the counterterm integrations, I will analytically show the successful cancellation of the explicit $\epsilon$ poles coming from the double-virtual contribution for processes with an arbitrary number of final-state coloured (and colourless) particles, eventually obtaining a compact (as well as analytic) finite remainder and a formula suitable for direct numerical implementation, paving the way to the production of relevant phenomenological results. Furthermore, I will discuss the recent next-to-leading-order (NLO) extension of the scheme to the treatment of initial-state radiation in massless QCD, along with its first complete numerical validation within MadNkLO, essential steps towards the full generalisation and automation of the subtraction algorithm.