Dominant Two-Loop Electroweak Correction to H -> gamma gamma
  We discuss a recent analysis of a dominant two-loop electroweak correction, of O(G_F M_t^2), to the partial width of the decay of an intermediate-mass Higgs boson into a pair of photons. The asymptotic-expansion technique was used in order to extract the leading dependence on the top-quark mass plus four expansion terms that describe the dependence on the W- and Higgs-boson masses. This correction reduces the Born result by approximately 2.5%. As a by-product of this analysis, also the O(G_F M_t^2) correction to the partial width of the Higgs-boson decay to two gluon jets was recovered. 
Bernd A. Kniehl