Three-loop electroweak corrections to the W-boson mass and sin2 θefflept in the large Higgs mass limit

We present an analytical calculation of the leading three-loop radiative correction to the S-parameter in the standard model in the large Higgs mass limit. Numerically, S-(3) = 1.1105 x g(4) / (1024 pi(3)) x m(H)(4) / M-W(4). When combined with the corresponding three-loop correction to the p- parameter, this leads to shifts of Delta((3)) sin(2)theta(lept)(eff) = 4.6 x 10(-9) x m(H)(4) / M-W(4) in the effective weak mixing angle and Delta M-(3)(W) = -6.3 x 10(-4) MeV x m(H)(4) / M-W(4) in the W-boson mass. For both of these observables, the sign of the three-loop correction is equal to that of the one-loop correction. (c) 2005 Elsevier B.V. All rights reserved.