Virtual top effects on low-mass Higgs interactions at next-to-leading order in QCD

We present the next-to-leading-order QCD corrections of O(αs2GFMt2) to the low-MH effective ℓ+ℓ− H, W+W− H, and ZZH interaction Lagrangians in the high-Mt limit. In the on-shell scheme formulated with GF, the O(αs2GFMt2) corrections support the O(αsGFMt2) ones and further increase the screening of the O(GFMt2) terms. The coefficients of (αsπ)2 range from −6.847 to −16.201, being in line with the value −14.594 recently found for Δϱ. All four QCD expansions converge considerably more rapidly, if they are written with μt = mt(μt), where mt(μ) is the MS mass, rather than the pole mass, Mt.