On Testing for New Couplings in Top Quark Decay

الأصل · EN

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. Associated with the latter (fₘ + fₑ) ambiguity, there are 3 very interesting numerical puzzles at the 0.1% level. This evidence for the presence of tensorial couplings in t-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 etaₗ = 0.46 (SM) due to the large interference between the W longitudinal/transverse amplitudes could exclude such tensorial couplings. Similarly, measurements of etaₗ and etaₗ' could resolve the case of a partially-hidden T-violation associated with the additional (fₘ + fₑ) coupling.