Higgs phenomenology in the Peccei-Quinn invariant NMSSM

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 (b) over bar events at m(b (b) over bar) similar or equal to 98GeV can be explained by a singlet-like 98GeV Higgs boson in the minimal PQ-NMSSM with low tan beta, stops around or below 1TeV, and light doublet-higgsinos around the weak scale.