What is the mass of the lightest supersymmetric Higgs boson?

Abstract

After reviewing briefly the upper bounds on the mass of the lightest Higgs boson in the most general unconstrained minimal supersymmetric extension of the Standard Model, we discuss various arguments which reduce the parameter space of the model and give stronger predictions for $M_{h^0}$. First, the constraints from the presently available experimental data are summarized. Next, the role of of several additional theoretical assumptions is studied, after extrapolating the model to high energy scales. The most important ones are: perturbative validity up to the GUT scale and the electroweak symmetry breaking. A Higgs boson with $M_{h^0}<$100 GeV is predicted in several scenarios. Its absence in that mass range will have important implications for the parameter space of the model.