Pseudo-observables in Higgs decays

Martín González-Alonso, Admir Greljo, Gino Isidori, David Marzocca
2015
We define a set of pseudo-observables characterizing the properties of Higgs decays in generic extensions of the Standard Model with no new particles below the Higgs mass. The pseudo-observables can be determined from experimental data, providing a systematic generalization of the "κ-framework" so far adopted by the LHC experiments. The pseudo-observables are defined from on-shell decay amplitudes, allow for a systematic inclusion of higherorder QED and QCD corrections and can be computed in
more » ... n be computed in any Effective Field Theory (EFT) approach to Higgs physics. We analyze the reduction of the number of independent pseudo-observables following from the hypotheses of lepton-universality, CP invariance, custodial symmetry, and linearly realized electroweak symmetry breaking. We outline the importance of kinematical studies of h → 4 decays for the extraction of such parameters and present their predictions in the linear EFT framework. Note Added. While this work was in its final stage, Ref. [35] appeared, where relations analogous to Eqs. (35,36) have been reported.
doi:10.5167/uzh-114909 fatcat:nl7qrsrv4vadta777wbdfhjlei