CP violation in e+e- -> t tbar: Energy Asymmetries and Optimal Observables of b and bbar Quarks

Abstract

The energy spectra of the b and bbar quarks in e+e- -> t tbar with t -> b W (tbar -> bbar W) are calculated assuming CP violation in the production process. Expressions for the corresponding CP violating asymmetries and optimal observables that determine the imaginary parts of the electric and weak dipole moment form factors of the top are derived. It is shown that polarization of the initial lepton beams is essential to disentangle Im d^{\gamma}(s) and Im d^{Z}(s). Numerical results are given in the Minimal Supersymmetric Standard Model with complex phases.