IRC-safe jet flavour without modifying anything

TL;DR

This paper presents a method to restore infrared-collinear safety in jet flavour definitions at NNLO in QCD without altering jet algorithms or experimental procedures, enabling direct comparison with standard measurements.

Contribution

It introduces an approach that maintains the standard jet and flavour definitions while ensuring infrared safety at NNLO, avoiding the need for new jet algorithms or analysis modifications.

Findings

Infrared safety violations are artefacts of calculations, not physical.

The method works at NNLO in QCD.

Predictions are directly comparable to standard anti-$k_T$ measurements.

Abstract

In this work, we describe how infrared-collinear safety can be restored perturbatively for standard definitions of jets and jet flavour. We will explicitly study this approach at next-to-next-to-leading order in QCD, where we will discuss the cause of the violation of infrared safety, argue that it is merely an artefact of the calculation, and explain how a consistent treatment of flavour removes this violation. The most important feature of our approach is that it does not require any changes to the definition of the jet or its flavour, nor does it modify the definition of the cross section. Consequently, the predictions can be directly compared to measurements performed using the standard anti-$k_T$ jet clustering algorithm, without the need for experimental collaborations to adapt their analyses to some new, infrared-collinear-safe definition of jet flavour, as would be the case for most - if not all - solutions presented in the literature thus far.