[SUNY BING 8/12/00] hep-ph/0106137 ON TESTING FOR NEW COUPLINGS IN TOP QUARK DECAY

To quantitatively assay future measurements of competing observables in t → W+b decay, we consider the gV−A coupling values of the helicity decay parameters versus those for “ (V − A) + Single Additional Lorentz Structures ”. There are 2 dynamical phase-type ambiguities (S + P ) and (fM + fE). Associated with the latter (fM + fE) ambiguity, there are 3 very interesting numerical puzzles at the mil level. This evidence for the presence of tensorial couplings in t → W+b decay is a consequence of the empirical value of mW /mt and the small, but non-zero, ratio mb/mt. Measurement of the sign of |ηL| = 0.46(SM) due to the large interference between the W longitudinal/transverse amplitudes would exclude such tensorial couplings. Similarly, sufficiently precise measurements of both ηL and ηL ′ could resolve the analogous dynamical ambiguity in the case of a partially-hidden T -violation associated with the additional fM + fE coupling. For Proceedings of ”IVth Rencontres du Vietnam” . Electronic address: cnelson @ binghamton.edu