An automated subtraction of NLO EW infrared divergences

TL;DR

This paper extends the Catani-Seymour dipole subtraction method to handle next-to-leading order electroweak divergences, enabling more accurate simulations of particle physics processes involving photon and gluon radiation.

Contribution

It introduces a comprehensive generalisation of the dipole subtraction scheme for NLO electroweak calculations, including simultaneous subtraction of QCD and electroweak singularities.

Findings

Successful implementation in Sherpa Monte-Carlo generator

Validation through internal consistency checks

Enhanced accuracy in NLO electroweak computations

Abstract

In this paper a complete generalisation of the Catani-Seymour dipole subtraction method to next-to-leading order electroweak calculations is presented. All singularities due to photon and gluon radiation off both massless and massive partons in the presence of both massless and massive spectators are accounted for. Particular attention is paid to the simultaneous subtraction of singularities of both QCD and electroweak origin which are present in the next-to-leading order corrections to processes with more than one perturbative order contributing at Born level. Similarly, embedding non-dipole-like photon splittings in the dipole subtraction scheme discussed. The implementation of the formulated subtraction scheme in the framework of the Sherpa Monte-Carlo event generator is detailed and numerous internal consistency checks validating the obtained results are presented.