Two Higgs Doublet Models

Abstract

Present data do not rule out the light neutral Higgs particle $h$ or $A$ in the framework of the general 2HDM. The discovery reach/exclusion limits of the Yukawa process $Z\to f\bar{f}h/A$, ($f=b$ quark or $\tau$ lepton) at LEP I and of the gluon-gluon fusion at HERA is discussed. In addition the possible search for very light Higgs particle in $\gamma \gamma$ fusion at low energy NLC is described.

6 pages, Invited Talk at the XXXIst Rencontres de Moriond, EW and Unified Theories, Les Arcs, March 16-23, 1996