# Search for vector-like leptons in multilepton final states in proton-proton collisions at $\sqrt{s}$ = 13 TeV

## TL;DR

This paper reports a search for vector-like leptons in multilepton final states at the LHC, setting the most stringent limits to date on their existence within a specific mass range, using CMS data from 2016-2017.

## Contribution

It presents the first comprehensive search for vector-like leptons coupling to third-generation leptons at 13 TeV, excluding masses from 120 to 790 GeV.

## Key findings

- No significant excess observed over the standard model background.
- Excludes vector-like lepton doublets with masses between 120 and 790 GeV at 95% CL.
- Sets the most stringent limits on such particles to date.

## Abstract

A search for vector-like leptons in multilepton final states is presented. The data sample corresponds to an integrated luminosity of 77.4 fb$^{-1}$ of proton-proton collisions at a center-of-mass energy of 13 TeV collected by the CMS experiment at the LHC in 2016 and 2017. Events are categorized by the multiplicity of electrons, muons, and hadronically decaying $\tau$ leptons. The missing transverse momentum and the scalar sum of the lepton transverse momenta are used to distinguish the signal from background. The observed results are consistent with the expectations from the standard model hypothesis. The existence of a vector-like lepton doublet, coupling to the third generation standard model leptons in the mass range of 120-790 GeV, is excluded at 95% confidence level. These are the most stringent limits yet on the production of a vector-like lepton doublet, coupling to the third generation standard model leptons.