Search for Excited Leptons in e+e- Annihilation at $\sqrt{s}$ = 130-140 GeV

Abstract

We report on a search for the excited leptons e*, mu*, tau* and nu* in e(+)e(-) collisions at root s = 130-140 GeV using the L3 detector at LEP. No evidence has been found for their existence. From an analysis of the expected pair produced l*l* in the channels ee gamma gamma, mu mu gamma gamma, tau tau gamma gamma, eeWW, and nu nu gamma gamma, We determine the lower mass limits at 95% C.L. of 64.7 GeV for e*, 64.9 GeV for mu*, 64.2 GeV for tau*, 57.3 GeV (eW decay mode) and 61.4 GeV (nu gamma decay mode) for nu*. From an analysis of the expected singly produced ll* in the channels ee gamma, mu mu gamma, tau tau gamma, nu eW and nu nu gamma, we determine upper limits on the couplings lambda/m(l*) up to m(l*) = 130 GeV.