Top-tagging: A Method for Identifying Boosted Hadronic Tops

TL;DR

This paper presents a jet substructure method for identifying boosted hadronic top quarks, significantly reducing background and enhancing resonance search capabilities in high-energy collider experiments.

Contribution

A novel top-tagging technique using jet substructure and kinematic constraints to distinguish top jets from light quark and gluon jets at high energies.

Findings

Achieves ~99% rejection of light quark/gluon jets at 1 TeV pT

Retains up to 40% of top jets

Reduces background for t-tbar resonance searches by a factor of ~10,000

Abstract

A method is introduced for distinguishing top jets (boosted, hadronically decaying top quarks) from light quark and gluon jets using jet substructure. The procedure involves parsing the jet cluster to resolve its subjets, and then imposing kinematic constraints. With this method, light quark or gluon jets with pT ~ 1 TeV can be rejected with an efficiency of around 99% while retaining up to 40% of top jets. This reduces the dijet background to heavy t-tbar resonances by a factor of ~10,000, thereby allowing resonance searches in t-tbar to be extended into the all-hadronic channel. In addition, top-tagging can be used in t-tbar events when one of the tops decays semi-leptonically, in events with missing energy, and in studies of b-tagging efficiency at high pT.