Limits on neutral heavy lepton production from Z0 decay

Data taken with the OPAL detector at LEP during a scan of the Z0 resonance were searched for evidence of neutral heavy leptons that decay via mixing. Four different decay modes of the neutral heavy lepton are considered: L0→eW*, L0→μW*, L0→τW*, and L0→νZ*. No evidence is seen of a neutral heavy lepton signal; branching fraction limits in the range of 10-3-10-4 are set for Z0→L0anti L0 and for Z0→νanti L0 (or anti νL0) relative to Z0→hadrons. (orig.)