Exact quark-mass dependence of the Higgs-photon form factor at three loops in QCD

TL;DR

This paper calculates the exact three-loop quark-mass dependence of the Higgs-photon form factor in QCD, enabling precise predictions of Higgs decay to two photons at higher orders.

Contribution

It extends previous work on the Higgs-gluon form factor to the Higgs-photon case, providing numerical master integrals and expansions for improved decay rate calculations.

Findings

Derived expansions around threshold and high-energy limits.

Provided numerical master integrals for the Higgs-photon form factor.

Facilitated next-to-next-to-leading order predictions of Higgs decay to photons.

Abstract

We follow up on our discussion of the exact quark-mass dependence of the Higgs-gluon form factor at three loops in QCD (arXiv:2001.03008) and turn our attention to the closely related Higgs-photon form factor. Similarly to our previous work, we intend to examine the form factor for the decay of a Higgs-boson with variable mass into two photons at the three-loop level in QCD. The set of master integrals is known numerically due to prior work on the Higgs-gluon form factor and is exploited to obtain expansions around the threshold as well as in the high-energy limit. Our results may be utilised to derive the photonic decay rate of the Higgs-boson through next-to-next-to-leading order.