Two--loop heavy Higgs corrections to the Higgs fermionic width

Abstract

We calculate the two--loop electroweak corrections to the fermionic decay width of the Higgs boson at leading order in $m_{H}$. The sum of one--loop and two--loop radiative corrections turns out to be at 6% level over the whole range of $m_{H}$ where the perturbation theory is supposed to be a sensible approximation. We show that the perturbative approach breaks down at $m_{H} \sim$ 1.4 TeV, and address the question of its relevance beyond this limit.