Transverse tau polarization in decays of the top and botton quarks in the Weinberg model ofCPnonconservation

We show that the transverse polarization asymmetry of the τ lepton in the decay t→bτν is extremely sensitive to CP violating phases arising from the charged Higgs boson exchange in the Weinberg model of CP nonconservation. Qualitatively, the polarization asymmetries are enhanced over rate or energy asymmetries by a factor of ≊${\mathit{m}}_{\mathit{t}}$/${\mathit{m}}_{\mathrm{\tau }}$∼100. Thus for optimal values of the parameters the method requires ≊${10}^4$ top pairs to be observable rather than ${10}^7$ needed for rate or energy asymmetries. We also examine τ polarization in b decays via b→cντ and find that it can also be very effective in constraining the CP violation parameters of the extended Higgs sector.