The automation of next-to-leading order electroweak calculations

TL;DR

This paper discusses the development of automated methods for calculating next-to-leading order electroweak corrections in particle physics, extending existing tools to handle mixed QCD and electroweak interactions.

Contribution

It introduces new features for automated NLO electroweak calculations, including the extension of FKS subtraction and the implementation in MadGraph5_aMC@NLO for mixed-coupling expansions.

Findings

Successfully computed NLO EW corrections for LHC processes

Extended FKS subtraction to include tagged particles and fragmentation functions

Demonstrated the capabilities of the new MadGraph5_aMC@NLO version

Abstract

We present the key features relevant to the automated computation of all the leading- and next-to-leading order contributions to short-distance cross sections in a mixed-coupling expansion, with special emphasis on the first subleading NLO term in the QCD+EW scenario, commonly referred to as NLO EW corrections. We discuss, in particular, the FKS subtraction in the context of a mixed-coupling expansion; the extension of the FKS subtraction to processes that include final-state tagged particles, defined by means of fragmentation functions; and some properties of the complex mass scheme. We combine the present paper with the release of a new version of MadGraph5_aMC@NLO, capable of dealing with mixed-coupling expansions. We use the code to obtain illustrative inclusive and differential results for the 13-TeV LHC.