Vectorlike leptons at the Large Hadron Collider

TL;DR

This paper evaluates the potential for detecting or excluding vectorlike leptons at the LHC, focusing on multilepton signatures and considering different isospin models, with implications for current and future collider data.

Contribution

It analyzes the detectability of vectorlike leptons decaying to tau leptons, highlighting the challenges for isosinglet models and the prospects for isodoublet models at different LHC energies.

Findings

Discovery is challenging for isosinglet models.

Exclusion possible for isodoublet models up to 275 GeV at 8 TeV.

Future LHC data at 13 TeV could improve exclusion and discovery prospects.

Abstract

We study the prospects for excluding or discovering vectorlike leptons using multilepton events at the LHC. We consider models in which the vectorlike leptons decay to tau leptons. If the vectorlike leptons are weak isosinglets, then discovery in multilepton states is found to be extremely challenging. For the case that the vectorlike leptons are weak isodoublet, we argue that there may be an opportunity for exclusion for masses up to about 275 GeV by direct searches with existing LHC data at sqrt{s}=8 TeV. We also discuss prospects for exclusion or discovery at the LHC with future sqrt{s}=13 TeV data.