Single top quark production ineγcollisions and testing technicolor models

Abstract

We study the single top quark production process ${e}^{+}\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\gamma}}t\overline{b}{\overline{\ensuremath{\nu}}}_{e}$ in various kinds of technicolor models in high energy $e\ensuremath{\gamma}$ collisions at the future ${e}^{+}{e}^{\ensuremath{-}}$ linear colliders. It is shown that if there is a certain charged pseudo-Goldstone-boson (PGB) coupling to $t\overline{b},$ the $t\overline{b}$-channel PGB contribution is dominant, but the situation is quite different from that in the neutral channel $\ensuremath{\gamma}\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\gamma}}t\overline{t}$ due to the destructive nature of different amplitudes. At the DESY linear collider TESLA, the event rates in models with $t\overline{b}$-channel PGB contributions, such as the top-color-assisted technicolor model, etc., are experimentally measurable. The ${e}^{+}\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\gamma}}t\overline{b}{\overline{\ensuremath{\nu}}}_{e}$ process provides a feasible test of technicolor models with $t\overline{b}$-channel charged PGB contributions.