Production of polarized (tau) pairs and tests of CP violation using polarized e(sup (plus minus)) colliders near threshold

摘要

We consider the production of (tau) pairs by electron-positron colliding beams at the maximum cross section near the threshold. At this energy (tau) pairs are produced mostly in the s-wave which implies that the spin of the (tau) pairs are 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 (tau) 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 (tau) pairs are discussed.