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 ($\frac{1-a_s}{\pi }$). While for a heavy Higgs boson $m_H\ge 2$ GeV), the QCD correction is small, for a lighter Higgs boson this correction is significant and could be drastic.