NNLO study of top-quark mass renormalization scheme uncertainties in Higgs boson production

The ambiguity in the choice of a renormalization scheme and scale for the top-quark mass leads to an additional source of theoretical uncertainty in the calculation of the Higgs boson production cross section via gluon fusion. These uncertainties were found to be dominant in the case of off-shell Higgs production at next-to-leading order in QCD for large values of the Higgs virtuality m(H)*. In this work, we study the uncertainties related to the top-quark mass definition up to next-to-next-to-leading order (NNLO) in QCD. We include the full top-quark mass dependence up to three loops in the virtual corrections, and evaluate the real contributions in the soft limit, therefore obtaining the so-called soft-virtual (SV) approximation. We construct NNLOSV predictions for off-shell Higgs boson production renormalizing the top-quark mass within both the on-shell (OS) and the (MS) over bar schemes, and study in detail the differences between them. While the differences between the two schemes are sizeable, we find that the predictions are always compatible within scale uncertainties. We also observe that the difference between renormalization schemes is largely reduced when increasing the order of the perturbative expansion. We analyze the quality of the convergence of the perturbative series in both schemes, and find that at large invariant masses the (MS) over bar results present much larger corrections than their OS counterparts. We also comment on the more complicated case of Higgs boson pair production.

Automated summary

This study investigates the theoretical uncertainties in the calculation of Higgs boson production due to the ambiguity in the choice of renormalization scheme and scale for top-quark mass. The results show that these uncertainties are dominant in the case of off-shell Higgs production with large Higgs virtuality. While predictions within the on-shell and MSbar schemes differ significantly, they remain compatible within scale uncertainties, with differences decreasing as the perturbative expansion order increases.