2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/206143A search for excited lepton production in e+e- collisions was performed using the data collected by the DELPHI detector at LEP at centre-of-mass energies ranging from 189 GeV to 209 GeV, corresponding to an integrated luminosity of approximately 600 pb^{-1}. No evidence for excited lepton production was found. In searches for pair-produced excited leptons, lower mass limits were established in the range 94 - 103 GeV/c^2, depending on the channel and model assumptions. In searches for singly-produced excited leptons, upper limits on the parameter f/Lambda were established as a function of the mass.31 pages, 12 figures, Accepted by Eur. Phys. J. CHigh Energy Physics - Experimenttext