Heavy-lepton polarization and radiative effects in e/sup +/e/sup -/ to tau /sup +/ tau /sup -/ near the Z/sup 0/-pole

Shows how the weak neutral couplings of charged heavy leptons can be measured in e/sup +/e/sup -/ to tau /sup +/ tau /sup -/ near the Z/sup 0/ mass with good sensitivity, once QED radiative effects are taken into account. The tau pairs are produced with a forward-backward asymmetry and with a net helicity due to the interference of electromagnetic and neutral-current amplitudes. These effects should be observed to some extent in the next generation of storage rings, where weak contributions are expected to modify the one-photon mechanism for mu -pair production by about 10% at square root s=30 Ge V. The smallness of the vector coupling through, together with the size of the point cross-section away from the Z/sup 0/-pole, is likely to limit the possible experimental information to the angular asymmetry in lepton-pair production, in which case the weak contribution is partially masked by higher-order electromagnetic effects. (10 refs).