First-order QCD corrections to the decay of the Higgs boson into two photons

The QCD corrections to the decay of the Higgs boson into two photons are renormalization-scheme independent. For a quark loop with ${m}_{q}$ larger than ${m}_{H}$, the corresponding amplitude should be decreased by a factor ($\frac{1\ensuremath{-}{a}_{s}}{\ensuremath{\pi}}$). While for a heavy Higgs boson ${m}_{H}\ensuremath{\ge}2$ GeV), the QCD correction is small, for a lighter Higgs boson this correction is significant and could be drastic.