Effective Multi-Higgs Couplings to Gluons
  Standard-Model Higgs bosons are dominantly produced via the gluon-fusion mechanism $gg \to H$ at the LHC, i.e. in a loop-mediated process with top loops providing the dominant contribution. For the measured Higgs boson mass of $\sim 125$ GeV the limit of heavy top quarks provides a reliable approximation as long as the relative QCD corrections are scaled with the full mass-dependent LO cross section. In this limit the Higgs coupling to gluons can be described by an effective Lagrangian. The same approach can also be applied to the coupling of more than one Higgs boson to gluons. We will derive the effective Lagrangian for multi-Higgs couplings to gluons up to N$^4$LO thus extending previous results for more than one Higgs boson. Moreover we discuss gluonic Higgs couplings up to NNLO, if several heavy quarks contribute. 
Michael Spira
hep-ph