STAGE-2 SPIN-CORRELATION FUNCTIONS - TESTS FOR NON-CKM-TYPE LEPTONIC CP VIOLATION IN TAU-]RHO-UPSILON DECAY

There are two tests for leptonic CP violation in tau --> rhonu decay b y inclusion of rho polarimetry observables in the energy correlation f unction for Z0 or gamma --> tau-tau+ --> (rho-nu) (rho+nuBAR). By CP invariance the moduli ratio of, and phase difference between, the two helicity amplitudes for tau- --> rho-nu(tau) decay should equal those for tau+ --> rho+nuBAR(tau) decay. The full angular distribution for t he above process, including the pi-/+ momentum direction versus that o f the rho-/+ momentum, can be used to test for such a non-CKM-type lep tonic CP violation in tau --> rhonu decay. Since this adds on spin-cor relation information from the next stage of decays in the decay sequen ce, we call such an energy-angular distribution a stage-two spin-corre lation (S2SC) function. Ideal statistical errors for tau --> rhonu dec ay are calculated for possible application at the Z0, at a B factory, or at the tau-charm threshold. S2SC functions should be useful for tes ting for possible non-CKM-type CP violation in top quark and in W boso n decay processes.