Production of polarized τ pairs and tests of CP violation using polarized e+/- colliders near threshold

We consider the production of τ pairs by electron-positron colliding beams at the maximum cross section near the threshold. At this energy τ pairs are produced mostly in the s wave which implies that the spin of the τ pairs is almost always pointing in the beam direction independent of the production angle. When both electrons and positrons are longitudinally polarized in the same direction, for example, 90%, one can obtain τ pairs with 99% polarization in the direction of the polarization vectors of the incident beams. Tests of CP violation and study of the structure of weak interactions using such polarized τ pairs is discussed.