THE NONMINIMAL SUPERSYMMETRIC STANDARD MODEL AT LARGE TAN-BETA

We present a comprehensive analysis of the Nonminimal Supersymmetric S tandard Model (NMSSM) for large values of tan beta, the ratio of the v acuum expectation values of the two Higgs doublets, which arise when w e impose the constraint of the unification of Yukawa couplings in the model. In this limit, we show that the vacuum expectation value of the singlet is forced to be large, of the order of 10 TeV. The singlet de couples from the lightest CP-even neutral Higgs boson and the neutrali nos. We compare our results with the corresponding particle spectrum o f the Minimal Supersymmetric Standard Model in the same limit. With th e exception of the lightest Higgs boson, the particle spectrum in the model turns out to be heavy. The Higgs boson mass, after the inclusion of radiative corrections, is found to be in the neighborhood of simil ar to 130 GeV.