H-->ggg(gqqbar) at Two Loops in the Large-M_t Limit
Carl R. Schmidt
TL;DR
The study tackles the need for high-precision QCD corrections to Higgs production via gluon fusion by computing two-loop helicity amplitudes for $H\rightarrow ggg$ and $H\rightarrow gq\bar{q}$ in the large-$M_t$ limit. It employs an effective $Hgg$ operator to reduce the problem to one-loop diagrams, using background-field gauge, spinor-helicity techniques, and dimensional regularization, with explicit ultraviolet renormalization and scheme considerations. The authors present detailed expressions for the two-loop amplitudes, including renormalization pieces and consistency checks such as pole cancellation and collinear limits. These results provide essential ingredients for NLO predictions of the Higgs transverse momentum distribution and form part of the NNLO gluon-fusion cross section in the large-$M_t$ regime, enhancing precision Higgs phenomenology at the LHC and offering a benchmark for future complete $M_t$-dependent calculations.
Abstract
We present a calculation of the two-loop helicity amplitudes for the processes H-->ggg and H-->gqqbar in the large-M_t limit. In this limit the calculation can be performed in terms of one-loop diagrams containing an effective Hgg operator. These amplitudes are required for the next-to-leading order (NLO) corrections to the Higgs transverse momentum distribution and the next-to-next-to-leading order (NNLO) corrections to the Higgs production cross section via the gluon fusion mechanism.