NEW NON-ABELIAN COUPLINGS AND RADIATIVE-CORRECTIONS TO THE MAIN DECAYOF THE TOP-QUARK

We calculate first order radiative corrections to the main decay of th e top quark, t --> b + W, beyond the Standard Model, by ''grafting'' o nto the standard lagrangian (using the terminology of de Rujula, Gavel a, Hernandez and Masso,), a new operator, which respects the gauge sym metry of the Standard Model and modifies the Z(o)W(+)W(-), gamma W+W- vertices. In our renormalization scheme we use alpha, G(F), M(z) as in put parameters. The m(t), dependence is given where we use Lambda = 1 TeV as a possible scale of the new physics. For m(t) = 150(200) GeV an d Lambda = 1 TeV, the maximal effect due to the new non-abelian coupli ngs, is to change the relative size of the electroweak radiative corre ctions of the Standard Model by adding a value of - 2.98(- 6.96)%, i.e . from a value of 5.55(3.26)% to 2.57(- 3.7)%.