IV.D337 — sin²θ_W NNLO Formula

NNLO Weinberg angle: iota*(1-iota)*(1 + (5/7)*iota^3 + (1/18)*iota^6) at -0.7 ppm from PDG MS-bar 0.23122. NNLO coefficient 1/18 = 1/W_4(3) = 1/(a3+a4+a5+a6).