Pseudoscalar Higgs boson production at hadron colliders in next-to-next-to-leading order QCD

We compute the total cross section for direct production of the pseudoscalar Higgs boson in hadron collisions at next-to-next-to-leading order (NNLO) in perturbative QCD. The $\mathcal{O}\left({\alpha }_s^2\right)$ QCD corrections increase the NLO production cross section by approximately 20–30%.