Search for Excited Leptons at \sqrt{s} = 189 GeV

TL;DR

This study searched for excited leptons at 189 GeV using the L3 detector, setting mass limits and coupling constraints, but found no evidence of their existence.

Contribution

First comprehensive search for excited leptons at LEP energy, establishing new mass limits and coupling constraints.

Findings

No evidence of excited leptons was observed.

Lower mass limits close to the kinematic limit were set.

Upper limits on couplings up to 189 GeV were derived.

Abstract

A search for excited leptons, e*, mu*, tau*, nu_e*, nu_mu*, and nu_tau* was performed with the L3 detector at LEP using data collected at a centre-of-mass energy of 189 GeV, corresponding to an integrated luminosity of 176 pb^{-1}. No evidence of their production is observed. From the searches for pair produced excited leptons, lower mass limits are set close to the kinematic limit. From the searches for singly produced excited leptons, upper limits on their couplings are derived in the mass range up to 189 GeV.