Singlet-like Higgs boson in the NMSSM

Abstract

We study the properties of the singlet-like Higgs boson in the next-to-minimal supersymmetric standard model. Scalar mixing depends on the higgsino mass parameter and the coupling of the singlet to the Higgs bilinear in the superpotential, which are constrained by the Large Electron-Positron Collider bound on the chargino mass and the perturbativity of the model to high energy scales, respectively. Using the relations between these parameters and mixing angles, we examine how strongly the singlet-like Higgs boson can couple to the standard model sector depending on its mass. In this paper, we consider the case in which the observed 125-GeV Higgs boson has properties very close to those predicted in the standard model, for which the singlet-like Higgs boson couples to the standard model sector via mixing with the heavy doublet Higgs boson. Interestingly the mixing turns out to be large either if the singlet-like Higgs boson is below a few hundred GeV or if tan β is moderate or large.