Search for excited leptons at 130–140 GeV

A search for the radiative decay of excited charged leptons, ℓ∗, and for radiative and weak decays of excited electron neutrinos, νe∗, is performed, using the 5.8 pb−1 of data collected by ALEPH at 130–140 GeV. No evidence for a signal is found in single or pair production. Excluded mass limits from pair production are close to 65 GeV/c2 for all excited lepton species. Limits on the couplings, λmℓ∗, of excited leptons are derived from single production. For an excited lepton mass of 130 GeV/c2, these limits are 0.04 GeV−1 for μ∗ and τ∗, and 0.0007 GeV−1 for e∗. For νe∗, the limit is at the level of 0.03 GeV−1 for a mass of 120 GeV/c2, independent of the decay branching ratios.