Search for Isolated Leptons in Low-Thruste+e−Annihilation Events ats=50 and 52GeV

Abstract

Multihadronic $e^{+}{e}^{-}$ annihilation events containing final-state leptons have been investigated with a 4.7-${\mathrm{pb}}^{-1\mathrm{}}$ data sample at c.m. energies of 50 and 52 GeV. The number of low-thrust events ($T\le 0.8$) with isolated leptons is consistent with the expectation of the standard model with five quark flavors. Limits on the production of new quarks and leptons are reported.