Gluon-fusion Higgs production in the Standard Model Effective Field Theory

We provide the complete set of predictions needed to achieve NLO accuracy in the Standard Model Effective Field Theory at dimension six for Higgs production in gluon fusion. In particular, we compute for the first time the contribution of the chromomagnetic operator $ \bar Q_L \Phi \sigma q_R G$ at NLO in QCD, which entails two-loop virtual and one-loop real contributions, as well as renormalisation and mixing with the Yukawa operator $\Phi^\dagger \Phi\, \bar Q_L \Phi q_R$ and the gluon-fusion operator $\Phi^\dagger \Phi\, GG$. Focusing on the top-quark-Higgs couplings, we consider the phenomenological impact of the NLO corrections in constraining the three relevant operators by implementing the results into the MadGraph5_aMC@NLO framework. This allows us to compute total cross sections as well as to perform event generation at NLO that can be directly employed in experimental analyses.