SQUARK CONTRIBUTIONS TO HIGGS-BOSON MASSES IN THE NEXT-TO-MINIMAL SUPERSYMMETRIC STANDARD MODEL

Within the context of an effective potential formalism we calculate the contribution to Higgs boson masses in the next-to-minimal supersymmetric standard model from squark loops. We then supplement a previously performed renormalisation group analysis of the Higgs sector of this model with these results in order to determine the shift in the bound on the lightest CP-even Higgs boson mass as a result of squark effects. The improved bound on the lightest neutral CP-even Higgs boson mass, including squark contributions, is m(h) less-than-or-equal-to 146 (139,149) GeV for m(t) = 90 (140,190) GeV. For m(t) = 190 GeV squark effects contribute 23 GeV to the bound, with smaller contributions for small m(t) values.