QCD corrections to associated Higgs boson production

We compute QCD corrections to the processes e⁺e^-→tt̄h⁰ and p→ptt̄h⁰ by treating the Higgs boson as a parton which radiates off a heavy quark. This approximation is valid in the limits Mₕ<<Mₜ and Mₕ,Mₜ<<√s. The corrections increase the rate for p→ptt̄h⁰ at the CERN LHC by a factor of $1.2$ to $1.5$ over the lowest order rate for an intermediate mass Higgs boson, Mₕ<1800ex0exGeV. The QCD corrections are small for e⁺e^-→tt̄h⁰ at √s=10ex0exTeV.