HIGGS TRIPLETS IN THE SUPERSYMMETRIC STANDARD MODEL

A supersymmetric standard model with an enlarged- Higgs sector can evade the strongest top-quark mass bounds from electroweak precision measurements as well as the tree-level bounds on the Higgs boson mass of the minimal model, provide new experimental signatures in the charged Higgs sector and still (technically) solve the m(Pl)/m(W) gauge-hierarchy problem. We explore in detail the simplest model satisfying all the above conditions. It contains a Higgs triplet with zero hypercharge and the most general (renormalizable) superpotential consistent with gauge invariance. We study the electroweak breaking and stability conditions of the scalar potential and the mass matrices and sum rules in the bosonic Higgs sector. We present approximate analytic formulae for mass eigenvalues and eigenstates for values of the rho-parameter very close to unity. We also make a numerical analysis of the allowed regions in the multi-parameter space and of mass spectra. Finally, a distinct feature of the model, unlike in the minimal model, is that gamma and Z have tree-level couplings to W+/- and C-/+ (the charged Higgses). We study the cross section for the process e+ e- --> W+/- C-/+ at present and future e+ e-colliders.