CP Violation in {\boldmath $H \ra t \overline{t}$} Decays at {\boldmath $\epem$} Colliders

Abstract

A helicity asymmetry for top quarks originating from Higgs boson decays is investigated within the 2-Higgs Doublet Model. The asymmetry is sensitive to CP violation in the scalar sector of the model, whereas it vanishes in the Standard Model. It has been checked that without any fine tuning of parameters the asymmetry can reach $50\%$. Standard decay patterns $\twbdec$ and $\tbwbdec$ are utilized as spin analyzers to measure the asymmetry. The Higgs production mechanism considered here is $\hprod$. It has been shown that signal from the asymmetry can easy overcome the noise for Higgs bosons produced in future linear $\epem$ colliders at energy $\sqrt{s}=500\gev$ operating with integrated luminosity $L=2.0\times10^4\lumun$.