Abstract
A
bstract
The Higgs boson decay to massive bottom quarks has the largest branching ratio. The decay is mainly induced by the bottom-quark Yukawa coupling with the decay rate calculated up to
$$ \mathcal{O}\left({\alpha}_s^4\right) $$
O
α
s
4
assuming the massless final-state bottom quark. The top-quark Yukawa coupling induced contribution starts at
$$ \mathcal{O}\left({\alpha}_s^2\right) $$
O
α
s
2
, and exhibits logarithmic and power enhancements, making the perturbative expansion converge slowly, which is a feature not present in the hadronic Higgs boson decay. We present a calculation of such contributions at
$$ \mathcal{O}\left({\alpha}_s^4\right) $$
O
α
s
4
to the decay into massive bottom quarks in which the squared amplitudes contain two top-quark Yukawa couplings and the final state must include at least a bottom quark pair. We find that they increase the decay width, relative to the result up to
$$ \mathcal{O}\left({\alpha}_s^3\right) $$
O
α
s
3
, by 0
.
4%, larger than the experimental precision at future lepton colliders, and reduce the scale dependence significantly down to 0
.
4%.