Effect of anomalous tbW vertex on decay-lepton distributions in e⁺ e⁻→tt̅ and CP-violating asymmetries

Abstract

We obtain analytic expressions for the energy and polar-angle double differential distributions of a secondary lepton l⁺ (l⁻) arising from the decay of t(t̅) in e⁺ e⁻→tt̅ with an anomalous tbW decay vertex. We also obtain analytic expressions for the various differential cross-sections with the lepton energy integrated over. In this case, we find that the angular distributions of the secondary lepton do not depend on the anomalous coupling in the decay, regardless of possible anomalous couplings occurring in the production amplitude for e⁺ e⁻→tt̅. Our study includes the effect of longitudinal e⁻ and e⁺ beam polarization. We also study the lepton energy and beam polarization dependence of certain CP-violating lepton angular asymmetries arising from an anomalous tbW decay vertex and compare them with the asymmetries arising due to CP-violation in the production process due to the top electric or weak dipole moment.