THE UPPER BOUND ON THE LIGHTEST HIGGS MASS IN THE NMSSM REVISITED

Abstract

We update the upper bound on the lightest CP-even Higgs mass in the NMSSM, which is given as a function of tan β and λ. It is pointed out that large values of tan β, with λ not too small, imply a large value for the MSSM-like parameter MA. We include the available one- and two-loop corrections to the NMSSM Higgs masses, and constraints from the absence of Landau singularities below the GUT scale as well as from the stability of the NMSSM Higgs potential. For m top varying between 171.4 and 178 GeV, squark masses of 1 TeV and maximal mixing the upper bound is assumed near tan β ~ 2 and varies between 139.9 and 141.4 GeV.