An NMSSM Without Domain Walls

We consider the Higgs sector in an extension of the MSSM involving an extra U(1)' gauge symmetry and SM singlet U(1)' charged scalars, in which the effective $\mu$ parameter is decoupled from the Z' mass. There are large mixings between Higgs doublets and singlets, significantly affecting the Higgs spectrum, production cross sections, decay modes, exclusion limits, and allowed parameters ranges. Scalars considerably lighter than 114 GeV are allowed, and the range $\tan \beta \sim 1$ is both allowed and theoretically favored. We concentrate on the lighter (least model dependent) Higgs particles with significant SU(2)-doublet components to their wave functions, for the case of no explicit CP violation in the Higgs sector. We consider their spectra, including the dominant radiative corrections to their masses in the large $\tilde t$ mass limit; production cross sections and exclusion limits at LEP and a future linear collider; and decay properties.