  For the t --> W b decay mode, an intensity-ratio equivalence for two distinct
Lorentz-invariant couplings is shown to be a consequence of symmetries of
tWb-transformations. Three explicit tWb-transformations connect the four
standard model's (SM) helicity amplitudes and the amplitudes in the case of an
additional chiral-tensorial-coupling of relative strength 53 GeV. Such a
coupling will arise if there is a large t_R --> b_L chiral
weak-transition-moment. Two commutator plus anti-commutator symmetry algebras
are generated from the 3 transformation matrices. Using these transformations,
the associated mass scales are related to the SM's electroweak scale v_EW =
246GeV$.
