'Energy Crisis' and Heavy Leptons

A pair of heavy leptons with a mass of 1.8 GeV can explain the step- function-like behavior of the charge-particle energy fraction in e$sup +$e$sup -$ annihilation except for the resonance region around 4.1 GeV. The preliminary result of the e-$mu$ events reported by Perl, in particular the effects of spin alignment, are discussed in terms of this heavy lepton. We comment on a possible way to distinguish the heavy lepton from heavy hadrons. (AIP)