Phenomenology of excited doubly charged heavy leptons at LHC

TL;DR

This paper investigates the production and detection prospects of doubly charged heavy leptons at the LHC, highlighting their decay signatures and potential to discover particles up to 1 TeV in mass.

Contribution

It provides the first detailed phenomenological analysis of doubly charged heavy leptons in composite models at LHC energies, including cross sections and detection sensitivity.

Findings

Sensitivity up to 600 GeV at 7 TeV run with 10-20 fb^-1

Sensitivity up to 1 TeV at 14 TeV run with 20-60 fb^-1

Invariant mass distribution shows a sharp endpoint for excited lepton mass

Abstract

We consider the production at the LHC of exotic composite leptons of charge Q=+2e. Such states are allowed in composite models which contain extended isospin multiplets (Iw=1 and Iw=3/2). These doubly charged leptons couple with Standard Model [SM] fermions via gauge interactions, thereby delineating and restricting their possible decay channels. We discuss the production cross section at the LHC of L++ (p p --> L++, l-) and concentrate on the leptonic signature deriving from the cascade decays L++ --> W+, l+ --> l+, l+, \nu_l i.e. p p --> l-, l+, l+, \nu_l showing that the invariant mass distribution of the like-sign dilepton has a sharp end point corresponding to excited lepton mass m*. We find that the sqrt{s}=7 TeV run is sensitive at the 3-sigma (5-sigma) level to a mass of the order of 600 GeV if L=10 fb^-1 (L=20 fb^-1). The sqrt{s}=14 TeV run can reach a sensitivity at 3-sigma (5-sigma) level up to m*=1 TeV for L=20 fb^-1 (L=60 fb^-1).