# SEMINAR

Extensions of the SM with N Higgs doublets
*Dr. Celso C. Nishi*
(**Inst. de Física Gleb Wataghin, Uni. Est. Campinas**)

**Sala P6, IST, Edifício Matemática**

**Friday, September 14th, 2007 at 02:00 PM**

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**Abstract**
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Extensions of the Standard Model with $N$ Higgs doublets (NHDMs) are simple extensions presenting a rich mathematical structure. An underlying Minkowski structure emerges from the study of both variable space and parameter space. The Minkowski parametrization enables one to impose sufficient
conditions for bounded below potentials, characterize certain classes of local minima and distinguish charge breaking vacua from neutral vacua. A particular class of
neutral minima presents a degenerate mass spectrum for the physical charged Higgs bosons. The presence of N Higgs doublets also enrichs the CP properties of the scalar potential where additional sources of explicit or spontaneous CP violation can be present. Nevertheless, general conditions for CP violation for the NHDM potential can be analyzed using group theoretical technics.
For the simplest two-Higgs-doublet model (2HDM) potential, a
minimum set of conditions for explicit and spontaneous CP violation is presented. The conditions can be formulated with CP-odd pseudoscalar invariants. General conditions can be also formulated for three or more Higgs doublets.`

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