Standard-Model-like scenarios in the 2HDM and Photon Collider potential.

After operations at the LHC and e[sup +]e[sup -] Linear Colliders it may be found that a Standard-Model-like scenario is realized. In this scenario no new particle will be discovered, except a single Higgs boson having partial widths or coupling constants with fundamental particles, whose squares are close, within anticipated experimental uncertainty, to those of the SM. Experiments at a Photon Collider can resolve whether the SM or e.g. the Two-Higgs-Doublet Model is realized in Nature. For the SM-like realizations of the 2HDM (II) we study the loop couplings of the Higgs boson with γγ and Zγ, and also with gluons. The deviation of the two-photon width from its SM value is generally higher than the expected inaccuracy in the measurement of Γ[sub γγ] at a Photon Collider. The deviation is sensitive to the parameters of the Higgs self interaction. [ABSTRACT FROM AUTHOR]