Study of heavy-lepton polarization in $e^{+}e^{-}$ annihilation at the $Z^{0}$ pole

The annihilation process into lepton pairs $e^{+}e^{-} \to l^{+}l^{-}$ in the proximity of the $Z^{0}$ peak yields information on the relative strength of the vector and axial couplings g/sub V/ and g /sub A/ through the cross-section energy dependence and the angular asymmetry of the final state leptons. The measurement of lepton polarization, besides providing a more sensitive test of the vector- axial mixture in the interaction, is the only way to determine the relative sign of g/sub V/ and g/sub A/, in the absence of polarized beams. The author studies the experimental feasibility of a measurement of longitudinal polarization on heavy leptons produced near the $Z^{0}$ pole.