THE HIGGS-PHOTON-Z BOSON COUPLING REVISITED

We analyze the coupling of; CP-even and CP-odd Higgs bosons to a photo n and a Z boson in extensions of the Standard Model. In particular, we study in detail the effect of charged Higgs bosons in two-Higgs doubl et models, and the contribution of SUSY particle loops in the minimal supersymmetric extension of the Standard Model. The Higgs-gamma Z coup ling can be measured in the decay Z --> gamma+Higgs at e(+)e(-) collid ers running on the Z resonance, or in the reverse process Higgs --> Z gamma with the Higgs boson produced at LHC. We show that a measurement of this coupling with a precision at the percent level, which could b e the case at future e(+)e(-) colliders, would allow to distinguish be tween the lightest SUSY and standard Higgs bosons in large areas of th e parameter space.