Top- and bottom-mass effects in hadronic Higgs production at small transverse momenta through LO+NLL

TL;DR

This paper analyzes the impact of top and bottom quark masses on the Higgs transverse momentum distribution in gluon fusion at small pT, finding the heavy-top approximation is accurate within 4%, but bottom effects are more significant.

Contribution

It provides a detailed study of mass effects in Higgs production at small transverse momenta, highlighting limitations of the heavy-top approximation and the challenges of including bottom-mass effects.

Findings

Heavy-top limit is accurate within 4% for pT < 150 GeV.

Bottom-mass effects can reach up to 10%.

Naive reweighting is insufficient for bottom-mass effects.

Abstract

The resummed transverse momentum distribution of the Higgs boson in gluon fusion through LO+NLL for small transverse momenta is considered, where the Higgs is produced through a top- and bottom-quark loop. We study the mass effects with respect to the infinite top-mass approach. The top-mass effects are small and the heavy-top limit is valid to better than 4% as long as the Higgs' transverse momentum stays below 150 GeV. When the bottom loop is considered as well, the discrepancy reaches up to about 10%. We conclude that bottom-mass effects cannot be included in a reasonable manner by a naive reweighting procedure in the heavy-top limit. We compare our results to an earlier, alternative approach based on POWHEG.