The H→ Zγ decay and $CP$ violation

The effects of $CP$-violation on the reported result by the LHC μZγ=2.2± 0.7 for the H→ Zγ signal strength are studied in new physics models, where bounds on the real and absorptive parts of the $CP$-violating form factor h₃Zγ are obtained, which are found to be less than 1.02 GeV. The leading order SM contributions to the H→ Zγ decay are also revisited, whereas contributions to the $CP$-violating form factor h₃Zγ from FCNC complex couplings mediated by the Z and H bosons are reported. Using the current bounds on such a couplings, where for these related to the Higgs boson are calculated to be or order 10⁻¹. We find that the FCNC contribution to h₃Zγ with top and charm quarks in the loop is of order 10⁻⁶. A generic model with new quarks is also studied. It is found a parameter space, which agrees with the H→γγ decay and the new μZγ LHC result.