David Marzocca (University of Zurich)
We introduce a set of pseudo-observables, defined from the on-shell amplitudes, characterizing the properties of Higgs decays in generic extensions of the Standard Model with no new particles below the Higgs mass. These provide a systematic generalization of the kappa framework used by the LHC experiments. The pseudo-observabls allow for a systematic inclusion of higher order QED and QCD corrections, and can be computed in any EFT approach to Higgs physics. Symmetries of the new-physics sector, such as CP invariance, lepton-universality, and custodial symmetry, imply relations among the pseudo-observables, which could be tested directly from Higgs data.