Pileup subtraction for jet shapes

TL;DR

This paper presents a novel event-by-event, jet-by-jet method to correct jet shape measurements for pileup effects at the LHC, improving the accuracy of analyses like quark-gluon discrimination and top-tagging.

Contribution

It introduces a general, mass-aware pileup correction technique applicable to various jet shapes, enhancing their robustness in high pileup conditions.

Findings

Effective pileup correction demonstrated in quark/gluon discrimination

Improved top-tagging performance with the new method

Method applicable to a wide range of jet shapes

Abstract

Jet shapes have the potential to play a role in many LHC analyses, for example in quark-gluon discrimination or jet substructure analyses for hadronic decays of boosted heavy objects. Most shapes, however, are significantly affected by pileup. We introduce a general method to correct for pileup effects in shapes, which acts event-by-event and jet-by-jet, and accounts also for hadron masses. It involves a numerical determination, for each jet, of a given shape's susceptibility to pileup. Together with existing techniques for determining the level of pileup, this then enables an extrapolation to zero pileup. The method can be used for a wide range of jet shapes and we show its successful application in the context of quark/gluon discrimination and top-tagging.