Search for excited leptons in e+e− collisions at

We have searched for excited states of charged and neutral leptons, e∗, μ∗, τ∗ and ν∗, in e+e− collisions at using the OPAL detector at LEP. No evidence for their existence was found. With the most common coupling assumptions, the topologies from excited lepton pair production include l+l−γγ and l+l−W+W−, with the subsequent decay of the virtual W bosons. From the analysis of these topologies, 95% confidence level lower mass limits of 79.9 GeV for e∗, 80.0 GeV for μ∗, 79.1 GeV for τ∗, 78.3 GeV for , 78.9 GeV for and 76.2 GeV for are inferred. From the analysis of W+W− and γγ topologies with missing energy and using alternative coupling assingments which favour charged l∗± and photonic ν∗ decays, 95% confidence level lower mass limits of 77.1 GeV for each l∗± flavour and 77.8 GeV for each ν∗ flavour are inferred. From the analysis of the l+l−γ, l±W∓ and single γ final states expected from excited lepton single production, upper limits on the ratio of the coupling to the compositeness scale, , are determined for excited lepton masses up to the kinematic limit.