COMPLETE MASS CORRECTIONS OF ORDER ALPHA(S)(2)M(B)(2)/M(Z)(2) TO THE AXIAL Z-BOSON DECAY-RATE IN THE LARGE TOP-MASS LIMIT

We analytically compute the QCD mass corrections of order alpha(s)2m(b)2/M(Z)2 to the decay rate of the Z-boson coming from anomalous ''double triangle'' diagrams which comprise single gamma5 matrices inside both of two closed fermion triangles. Coupled with our previous results, the present calculation determines the complete next to leading alpha(s)2 corrections to the leading power suppressed term of order m(b)2/M(Z)2 in the axial part of the decay rate of the Z-boson. Numerically, the anomalous diagrams lead to a further decrease of the (already quite small) corrections.