Pulling the Higgs and Top needles from the jet stack with Feature Extended Supervised Tagging

TL;DR

This paper introduces Feature Extended Supervised Tagging (FEST), a novel jet tagging method that incorporates charged lepton features within jets to improve discrimination of Higgs, top, and QCD jets, enhancing new physics searches.

Contribution

The paper presents FEST, a new jet tagging technique that leverages lepton features for improved discrimination of boosted particles and QCD jets, outperforming existing methods.

Findings

Achieves light jet rejection factors of 10^4-10^5 at 0.5 efficiency.

Effectively discriminates Higgs bosons from top quarks with rejection factors of 100-300.

Enhances sensitivity to new physics, demonstrated in Z' to ZH search.

Abstract

Jet tagging has become an essential tool for new physics searches at the high-energy frontier. For jets that contain energetic charged leptons we introduce Feature Extended Supervised Tagging (FEST) which, in addition to jet substructure, considers the features of the charged lepton within the jet. With this method we build dedicated taggers to discriminate among boosted $H \to \ell \nu q \bar q$, $t \to \ell \nu b$, and QCD jets (with $\ell$ an electron or muon). The taggers have an impressive performance, allowing for overall light jet rejection factors of $10^4-10^5$, for top quark / Higgs boson efficiencies of $0.5$. The taggers are also excellent in the discrimination of Higgs bosons from top quarks and vice versa, for example rejecting top quarks by factors of $100-300$ for Higgs boson efficiencies of $0.5$. We demonstrate the potential of these taggers to improve the sensitivity to new physics by using as example a search for a new $Z'$ boson decaying into $Z H$, in the fully-hadronic final state.