Peccei-Quinn invariant extension of the NMSSM

TL;DR

This paper proposes a Peccei-Quinn invariant extension of the NMSSM that addresses tadpole and domain wall issues, introduces a light singlino-dominated neutralino, and explores its phenomenological implications within a grand unified framework.

Contribution

It presents a novel PQ-invariant NMSSM extension that naturally generates the Higgs mu term and provides a UV completion within SU(5) GUT, avoiding common theoretical problems.

Findings

The model produces a light singlino-dominated neutralino.

Constraints from Z-boson decay limit the singlet-Higgs coupling.

The Higgs boson properties are consistent with experimental bounds.

Abstract

We study a Peccei-Quinn invariant extension of the next-to-minimal supersymmetric Standard Model (NMSSM), which turns out to be free from the tadpole and domain wall problems. Having a non-renormalizable coupling to the axion superfield, the SM singlet added to the Higgs sector can naturally generate an effective Higgs mu term around the weak scale. In the model, the lightest neutralino is dominated by the singlino, which gets a mass only through mixing with the neutral Higgsinos. We explore the phenomenological consequences resulting from the existence of such a relatively light neutralino. The coupling of the SM singlet to the Higgs doublets is constrained by the experimental bound on the invisible Z-boson decay width. Under this constraint, we examine the properties of the SM-like Higgs boson paying attention to its mass and decays. We also demonstrate a UV completion of the model in SU(5) grand unified theory with a missing-partner mechanism.