CERN Accelerating science

Internal Note
Report number	CERN-ALEPH-97-071 ; CERN-ALEPH-PHYSIC-97-062
Title	Search for Excited Leptons at 161-172 GeV
Author(s)	Medcalf, T ; Von Wimmersperg-Töller, J H
Affiliation	(CERN)
Collaboration	ALEPH Collaboration
Submitted to	International Europhysics Conference on High-Energy Physics, Jerusalem, Israel, 19 - 25 Aug 1997
Submitted by	19 Aug 1997
Subject category	Particle Physics - Experiment
Accelerator/Facility, Experiment	CERN LEP ; ALEPH
Abstract	A search for the radiative decay of excited leptons, $\ls$ and $\ns$, and for the weak decay of excited electron neutrinos, $\ns_e$, was undertaken using the $21.8\ipb$ of data collected by ALEPH at 161--$172\gev$, No evidence for a signal was found in single or pair production. Excluded mass limits from pair production are close to 85$\gevcc$ for excited charged leptons and 80.5$\gevcc$ for excited neutrinos. Limits on the couplings, $\lambda/m_{\ls}$, of excited leptons were derived from single production. For an excited lepton mass of 150$\gevcc$, these limits are 0.0004, 0.007, 0.01 and $0.015\gev^{-1}$, for $\es$, $\ms$, $\ts$, and $\ns_{\mu,\tau}$ respectively. For $\ns_e$ the limit is below $0.007\gev^{-1}$ for masses up to $150\gevcc$, independently of the branching ratios of the decays