Two-loop $gg \to Hg$ amplitude mediated by a nearly massless quark
  We analytically compute the two-loop scattering amplitude $gg \to Hg$ assuming that the mass of the quark, that mediates the ggH interaction, is vanishingly small. Our computation provides an important ingredient required to improve the theoretical description of the top-bottom interference effect in Higgs boson production in gluon fusion, and to elucidate its impact on the Higgs boson transverse momentum distribution. 
Kirill Melnikov, Lorenzo Tancredi, Christopher Wever
hep-ph