New preliminary combined results from the LEP experiments on searches for the Higgs boson beyond the Standard Model are presented. The new determination of the top quark mass at the Tevatron in 2004 influences the interpretations of the LEP results in both, the Standard Model, and the Minimal Supersymmetric extension of the Standard Model. Higgs boson physics will also be a major research area ...

A complete study of the Higgs sector of the SU(3)c ⊗ SU(3)L ⊗ U(1)X model is carried out, obtaining all possible cases of vacuum expectation values that permit the spontaneous symmetry breaking pattern SU(3)L ⊗U(1)X → SU(2)L ⊗ U(1)Y → U(1)Q. We find the most general Higgs potentials that contain three triplets of Higgs and one sextet. A detailed study of the scalar sector for different models w...

The search for the Higgs boson, the last missing particle in the Standard Model (SM) responsible for the electroweak symmetry breaking, is a primary goal of the CERN Large Hadron Collider (LHC), and is a central part of Fermilab’s Tevatron program. In the Standard Model, mass generation is triggered by the Higgs mechanism, which predicts the existence of one scalar particle, the Higgs boson [1]...

Fermion mass effects on Γ(Z → b ¯ b + a light Higgs) in a two-Higgs-doublet model Abstract Large fermion mass effect on the Yukawa process Z → b ¯ b → b ¯ bh(A) in the entire range of the neutral Higgs boson masses is found. It is particularly important for light Higgs bosons, which are still not excluded experimentally in a general two-Higgs-doublet model. The light Higgs bosons in the context...

We analyze the Higgs sector in the Next-to-Minimal Supersymmetric Standard Model, emphasizing the possibility of a light CP-odd scalar (axion) in the spectrum. We compute the coupling of the Standard-Model-like Higgs boson to a pair of axions, and show that it can be large enough to modify the Higgs branching fractions, with a significant impact on the Higgs searches. We delineate the range of ...

After a brief discussion of the mass of the Higgs in supersymmetry, I introduce λSUSY, a model with an extra chiral singlet superfield in addition to the MSSM field content. The key features of the model are: the superpotential W = λSHdHu with a large coupling λ and the resulting lightest Higgs with mass above 200GeV. The main part of my contribution will be about how λSUSY manifests itself at ...

We obtain tree-level unitarity constraints for the most general Two Higgs Doublet Model (2HDM) with explicit CP-violation. We briefly discuss correspondence between possible violation of tree level unitarity limitation and physical content of the theory. The Electroweak Symmetry Breaking in the Standard Model is described usually with the Higgs mechanism. In its simplest variant, an initial Hig...

It is unlikely that a high statistics study of r-lepton decays will be sensitive to the Higgs boson sector of electroweak physics. A Tau-Charm Factory is an ideal facility for the study of rare deca.ys of the rlepton. At a machine discussed in these Proceedings, one might expect to produce on the order of lo7 r’s per year. It is an interesting exercise to consider whether such a data sample is ...