Higgs boson masses in no-scale supergravity

We explore the Higgs sector of the minimal supersymmetric 'no-scale' unified model with the inclusion of radiative corrections which modify the usual tree-level Higgs mass relations. In the process, we rederive the complete allowed parameter space of the model using the one-loop effective potential. Our results can be compared with previous, generic analyses, where restrictive assumptions regarding low-energy supersymmetry breaking and squark mixing terms have been made. We find that in this class of models the lightest Higgs boson is always the lightest CP-even mass eigenstate (h), with mh> or approx.MW for a large portion of the allowed parameter space, and mbmax≅115 GeV an absolute upper bound. For low values of m1/2 (e.g., m1/2< or approx.150 GeV), the heavier Higgses (A, H, H+) lie mostly in the intermediate mass region (MW-2MZ), and become increasingly heavier and degenerate as m1/2 grows. Depending on the sign of μ, we obtain an upper bound on m1/2 which leads to absolute upper bounds on all Higgs masses. Finally, we discuss the relevant Higgs decay signatures at LEP and hadron colliders which may reveal their existence. (orig.)