Non-perturbaitve effects in Higgs boson decays to electroweak vector bosons and photons

TL;DR

This paper estimates non-perturbative QCD corrections to Higgs decays into gamma Z and gamma gamma, showing they are negligible compared to experimental precision at current and future colliders.

Contribution

It provides the first estimate of non-perturbative effects on these Higgs decay channels, highlighting their minimal impact.

Findings

Non-perturbative corrections are about 10^{-5} of decay rates.

Light-quark contributions are suppressed by small Yukawa couplings.

Corrections are negligible for current and future collider measurements.

Abstract

We estimate the magnitude of the leading non-perturbative QCD corrections to the decays of the Higgs boson to the $\gamma Z$ and $\gamma \gamma$ final states. These corrections originate from the light-quark contributions to such decays. We show that the non-perturbative effects are suppressed by the small Yukawa couplings of light quarks, but that there is no further quark-mass suppression. This is at variance with what is found in the standard perturbative calculations of the light-quark contributions. We demonstrate that the non-perturbative corrections modify the $H \to \gamma Z$ and $H \to \gamma \gamma$ decay rates by $O(10^{-5})$, well below the expected precision with which such decays can be studied both at the high-luminosity LHC and at future colliders.