Search for Heavy Neutral and Charged Leptons in e${}^{+}$e${}^{-}$ Annihilation at $\sqrt{s}$ = 183 and 189 GeV

L3 Collaboration

A search for unstable neutral and charged heavy leptons as well as for stable charged heavy leptons is performed at center-of-mass energies $\sqrt{s}$ = 183 and 189 GeV with the L3…