An NMSSM Without Domain Walls

TL;DR

This paper explores an extended NMSSM model with an extra U(1)' gauge symmetry, analyzing its Higgs sector, spectrum, and collider phenomenology, highlighting the possibility of lighter Higgs bosons and the impact of Higgs-singlet mixings.

Contribution

It introduces a variant of the NMSSM with an additional U(1)' symmetry, decoupling the ppa parameter from the Z' mass and studying its implications on Higgs phenomenology.

Findings

Lighter Higgs bosons below 114 GeV are possible.

The eta  region is both allowed and theoretically favored.

Significant Higgs-singlet mixing affects collider signals.

Abstract

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.