TAU-SPIN CORRELATIONS AT THE Z-PEAK - APLANARITIES OF THE DECAY PRODUCTS

The production of tau-pairs at the Z peak leads to interesting dynamical information contained in their spin density matrix. Besides the longitudinal polarization of each tau-lepton, there are two independent spin-spin correlations associated with the transverse (within the production plane) and normal (to the production plane) polarization components. The transverse-normal spin correlation is both a parity-odd and time reversal-odd observable. We analyze the correlated angular distribution of the decay products as polarization analyzers of the tau+tau- system. We find two azimuthal asymmetries of the decay products and the incoming beam, which are able to disentangle these spin correlation observables without reconstructing the tau-direction.