Exotic Seesaw-Motivated Heavy Leptons at the LHC

TL;DR

This paper explores the potential for the LHC to discover heavy leptons predicted by a seesaw model, highlighting their production, decay signatures, and detectability at current collider energies.

Contribution

It demonstrates the LHC's capability to detect TeV-scale exotic leptons with unique decay signatures, providing a test for the seesaw-motivated heavy lepton model.

Findings

Abundant production of Sigma leptons at 7 TeV LHC for 400 GeV mass.

Potential to observe same-sign dilepton events from Sigma decays.

Identification of specific decay signatures like Sigma^{+++} to W^\pm W^\pm l^\pm.

Abstract

We study the LHC potential for discovering TeV-scale SU(2)_L 5-plet fermions introduced recently to explain small neutrino masses. We show that the Drell-Yan production and the decays of new exotic Sigma leptons are testable at the LHC. Their production is abundant due to nontrivial electroweak gauge charges. For 1 fb^-1 of integrated luminosity at the present LHC sqrt{s}=7 TeV, there can be 270 Sigma-Sigmabar pairs produced for M_Sigma = 400 GeV. Besides producing same-sign dilepton events, they could lead, due to a chosen small mixing between heavy and light leptons, to ~10 golden decays Sigma^{+++}(Sigma^{+++}-bar) --> W^\pm W^\pm l^\pm with a specific decay signature.