Non-Minimal Higgs Sectors: The Decoupling Limit and its Phenomenological Implications

In models with a non-minimal Higgs sector, a decoupling limit can be defined. In this limit, the masses of all the physical Higgs states are large (compared to the scale of electroweak symmetry breaking) except for one neutral CP-even Higgs scalar, whose properties are indistinguishable from the Higgs boson of the minimal Standard Model. The decoupling limit of the most general CP-conserving two-Higgs doublet model is formulated. Detection of evidence for a non-minimal Higgs sector at future colliders in the decoupling limit may present a formidable challenge for future Higgs searches. Invited Talk presented at the Workshop on Electroweak Symmetry Breaking, Eötvös University Budapest, Hungary, 11–13 July 1994, and at the Workshop on Physics from the Planck Scale to the Electroweak Scale, University of Warsaw, Poland, 21–24 September, 1994. ⋆ Work supported in part by the U.S. Department of Energy.