Singe Top Production at LEP 200

Abstract

We present exact tree level cross sections for the single top production process $e^{-}{e}^{+}\to e^{-}{\bar{\nu }}_{e}t\bar{b}$ at LEP~200. The results reproduce roughly those obtained earlier by using the equivalent real photon approximation and we confirm the observation that detecting a top heavier than half the c.m.~energy is not feasible at LEP~200. The calculation has been performed by a new automatic Feynman amplitude generator MadGraph which produces HELAS code for the helicity amplitudes.

Comments: 7 pages, 4 postscript figures