Two Photon Decay Widths of Non-Standard Higgs Bosons.

This thesis examines the two photon decay widths of non-standard Higgs bosons. These widths are calculated for Two-Higgs-Doublet models in general, and for the minimal broken supersymmetry model in particular. For Two-Higgs -Doublet models a large enhancement of these widths relative to the standard model is possible. This in turn leads to larger production rates for the spin-0 bosons in ep and e('+)e('-) colliders. However, we find that for the minimal broken supersymmetry case, a severe upper bound on this possible enhancement is imposed by the supersymmetry features. We find that while the Higgs bosons of the Two -Higgs-Doublet model could possibly be produced at readily observable rates with the HERA collider, this will not be the case in the minimal supersymmetry model. Hence detection of these Higgs bosons could provide an experimental test of supersymmetry, which would rule out the minimal model.