  For the " t --> W b " decay mode, an intensity-ratio equivalence-theorem for
two Lorentz-invariant couplings is shown to be related to symmetries of
tWb-transformations. Explicit tWb-transformations, A_{+}=M A_{SM}, P A_{SM}, B
A_{SM} relate the four standard model's helicity amplitudes and those in the
case of an additional " t_R --> b_L " weak-moment of relative strength "
Lambda_{+} =E_W /2 = 53 GeV ". Two commutator plus anti-commutator symmetry
algebras are generated from M, P, B. These transformations enable a
characterization of the associated mass scales.
