Littlest Higgs model and top-charm production at high-energy linear colliders

Abstract

Due to the presence of extra top quark T in the little Higgs models, the $CKM$ matrix is not unitary and the flavor changing neutral currents may exist at the tree level. In the context of the Littlest Higgs(LH) model, we discuss the top-charm production at the high-energy linear $e^{+}{e}^{-}$ collider $(LC)$ via the processes $e^{+}{e}^{-}\to \bar{t}c+t\bar{c}$, $e^{+}{e}^{-}\to (\bar{t}c+t\bar{c}){\nu }_e\overline{{\nu }_e}$, and $e^{-}\gamma \to e^{-}\bar{t}c$. We find that the resonance production cross section for the process $e^{+}{e}^{-}\to \bar{t}c+t\bar{c}$ is significantly larger, which can be detected in future $LC$ experiments.

Comments: latex files, 13 pages, 5 figures. References added and some typos corrected