Energy Spectrum of Secondary Leptons in $e^+e^-\to t\bar{t}:$ --- Nonstandard Effects and CP Violation ---

Process of top-quark pair production at future high-energy $e^+e^-$ linear colliders has been investigated as a possible test of physics beyond the Standard Model. Non-standard interactions have been assumed both for the production and for the subsequent decay of top quarks. Energy spectrum of a single lepton and energy correlation of $\ell^+$ and $\ell^-$ emerging from the process $e^+e^-\rightarrow t\bar{t}\rightarrow \ell^+\ell^-X$ are calculated. Energy-spectrum asymmetry of the final leptons is considered as a measure of $CP$ violation. An optimal method for detecting $CP$ violation in the production {\it and} decay process has been proposed.