Top- and bottom-mass effects in hadronic Higgs production at small   transverse momenta through LO+NLL
  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. 
Hendrik Mantler and Marius Wiesemann
hep-ph