Search for excited leptons in Z0 decay

ALEPH Collaboration (1990) Search for excited leptons in Z0 decay. Physics Letters B, 236 (4). pp. 501-510. ISSN 0370-2693

Abstract

We have looked for evidence of excited lepton production in Z0 decay observed in the ALEPH detector at LEP. We find no ℓℓγγ events and set new limits at 95% CL on ℓ∗ masses at 44.6, 44.6 and 41.2 GeV/c2 for respectively. Observed events in the ℓℓγ channels are consistent with radiative effects and we set limits for the first time on the coupling for ℓ∗ masses in the range up to 86 GeV/c2.