Higgs phenomenology in the Peccei-Quinn invariant NMSSM

TL;DR

This paper explores Higgs phenomenology within the Peccei-Quinn invariant NMSSM, highlighting how the model's unique features influence Higgs properties and can explain certain LEP experimental excesses.

Contribution

It introduces the Higgs phenomenology specific to the PQ-NMSSM, emphasizing the impact of the Peccei-Quinn symmetry on scalar mixing and Higgs signatures.

Findings

Scalar mixing constraints are tighter due to the light singlino-like neutralino.

A 98 GeV singlet-like Higgs can explain LEP excesses under certain parameters.

The model accommodates low tanβ, TeV-scale stops, and light higgsinos.

Abstract

We study the Higgs phenomenology in the Peccei-Quinn invariant NMSSM (PQ-NMSSM) where the low energy mass parameters of the singlet superfield are induced by a spontaneous breakdown of the Peccei-Quinn symmetry. In the generic NMSSM, scalar mixing among CP-even Higgs bosons is constrained by the observed properties of the SM-like Higgs boson, as well as by the LEP bound on the chargino mass and the perturbativity bound on the singlet Yukawa coupling. In the minimal PQ-NMSSM, scalar mixing is further constrained due to the presence of a light singlino-like neutralino. It is noticed that the $2\sigma$ excess of the LEP $Zb\bar b$ events at $m_{b\bar b}\simeq$ 98 GeV can be explained by a singlet-like 98 GeV Higgs boson in the minimal PQ-NMSSM with low $\tan\beta$, stops around or below 1 TeV, and light doublet-higgsinos around the weak scale.