Higgs characterisation at NLO in QCD: CP properties of the top-quark Yukawa interaction

At the LHC the CP properties of the top-quark Yukawa interaction can be probed through Higgs production in gluon fusion or in associationwith top quarks. We consider the possibility for both CP-even and CP-odd couplings to the top quark to be present, and study CP-sensitive observables at next-to-leading order (NLO) in QCD, including parton-shower effects. We show that the inclusion of NLO corrections sizeably reduces the theoretical uncertainties, and confirm that di-jet correlations in H + 2 jet production through gluon fusion and correlations of the top-quark decay products in t (t) over barH production can provide sensitive probes of the CP nature of the Higgs interactions.