Top-Quark Detection at High-Energy Electron-Positron Colliders

Top-quark $t$ production via $e^{-}{e}^{+}\to \mathrm{tt}$ with one of $t$,$t$ decaying semileptonically and the other decaying into jets is considered for possible observation at the Stanford Linear Collider and the CERN colliders LEP I and II. It is shown that, with proper procedures involving a series of acceptance cuts, $t$ quarks with masses $m_t\lesssim 70$ GeV can be identified, the higher masses ($50\lesssim m_t\lesssim 70$ GeV) being accessible only at LEP II.