This talk concerns some theoretical patterns of the helicity amplitudes for t --> W b decay. The patterns involve both the standard model's four decay helicity amplitudes, A_{ SM}, and also the amplitudes A_{ +} in the case of an additional t_R --> b_L tensorial coupling of relative strength \Lambda_{ +} =E_W /2 = 53 GeV. Such an additional electroweak coupling would arise if the observed top-quark has a large chiral weak-transition-moment. The A_{ +} amplitudes are interpreted as corresponding to the observed top-quark decays. Three tWb-transformations A_{ +}=M A_{ SM}, ..., are used in simple characterization of the values of \Lambda_{ +}, and of the mass ratios m_W/m_t, and m_b/m_t. Measurement of the sign of the \eta_L = +/- 0.46 helicity parameter, respectively for SM/+, due to the large interference between the W-longitudinal and W-transverse amplitudes, could exclude such a chiral weak-transition-moment in favor of the SM prediction.
Categories: hep-ph