Searching for an exotic lepton and gauge boson at high-energy e+e- colliders.

The possibility of searching in high energy e+ecollisions for a singly produced heavy lepton with an ordinary light lepton e+e+ L+t?, has been investigated. The search is motivated mainly by its distinctive experimental signatures. In a data sample corresponding to an inte grated luminosity of 30 fb-’ collected at a 1 TeV e+ecollider, the search is sensitive to a lepton of mass up to about 1 TeV/c2 and a production cross section as low as 10% of the p-pair point cross section. For the case where the process is mediated by an exotic gauge boson, sensitivity to a gauge boson of mass up to about 2 TeV/c2 can be achieved.