Fatjet signatures of heavy neutrinos and heavy leptons in a left-right model with universal seesaw at the HL-LHC

TL;DR

This paper investigates the detection of boosted heavy neutrinos and leptons via fatjet signatures at the HL-LHC within a left-right symmetric model featuring a universal seesaw mechanism, highlighting new search strategies.

Contribution

It introduces a novel collider search method using fatjet substructure variables to identify heavy leptons in a left-right symmetric model with universal seesaw at the HL-LHC.

Findings

Effective background suppression using $LSF$ and $LMD$ variables.

Potential for robust discovery of heavy leptons at HL-LHC.

Enhanced sensitivity compared to traditional search techniques.

Abstract

We perform a collider search for fatjet signals originating from boosted heavy neutral and charged leptons with masses between a few hundred GeV to a TeV. These heavy leptons originate from the decay of heavy gauge bosons with masses above 4 TeV in a left-right symmetric extension of the Standard Model (SM), which considers a universal seesaw mechanism for the generation of all the SM fermion masses. The fatjet signals arise naturally in this model due to the presence of heavy seesaw partners of the SM fermions which decay to SM gauge bosons carrying large boosts. We employ substructure based variables lepton sub-jet fraction ($LSF$) and lepton mass drop ($LMD$) together with kinematic variables of fatjets to look for fatjet signals associated with non-isolated leptons. These variables help in reducing the SM backgrounds while retaining enough statistics for signal events, which leads to a robust discovery potential at the high-luminosity Large Hadron Collider (HL-LHC).