Higgs Decay to Order \alpha_s^4

TL;DR

This paper calculates the three-loop QCD correction to the Higgs boson decay into gluons, significantly refining the theoretical prediction of its decay width for intermediate mass Higgs bosons.

Contribution

It provides the first analytic form of the three-loop O() correction to Higgs decay to gluons, improving the precision of theoretical predictions.

Findings

The three-loop correction increases the decay width by about 1%.

The correction factor at M_H=100 GeV is approximately 1+0.66+0.21.

The correction reduces the uncertainty in Higgs decay predictions.

Abstract

We present in analytic form the three-loop O(\alpha_s^2) correction to the H -> gg partial width of the standard-model Higgs boson with intermediate mass M_H << 2 M_t. Its knowledge is required because the O(\alpha_s) correction is so sizeable that the theoretical prediction to this order is unlikely to be reliable. For M_H=100 GeV, the resulting QCD correction factor reads $1+(215/12)\alpha_s^{(5)}(M_H)/\pi+150.419 (\alpha_s^{(5)}(M_H)/\pi)^2 \approx 1+0.66+0.21$. The new three-loop correction increases the Higgs-boson hadronic width by an amount of order 1%.