Singlet-doublet Higgs mixing and its implications on the Higgs mass in the PQ-NMSSM

We examine the implications of singlet-doublet Higgs mixing on the properties of a Standard Model (SM)-like Higgs boson within the Peccei-Quinn invariant extension of the NMSSM (PQ-NMSSM). The SM singlet added to the Higgs sector connects the PQ and visible sectors through a PQ-invariant non-renormalizable K\"ahler potential term, making the model free from the tadpole and domain-wall problems. For the case that the lightest Higgs boson is dominated by the singlet scalar, the Higgs mixing increases the mass of a SM-like Higgs boson while reducing its signal rate at collider experiments compared to the SM case. The Higgs mixing is important also in the region of parameter space where the NMSSM contribution to the Higgs mass is small, but its size is limited by the experimental constraints on the singlet-like Higgs boson and on the lightest neutralino constituted mainly by the singlino whose Majorana mass term is forbidden by the PQ symmetry. Nonetheless the Higgs mixing can increase the SM-like Higgs boson mass by a few GeV or more even when the Higgs signal rate is close to the SM prediction, and thus may be crucial for achieving a 125 GeV Higgs mass, as hinted by the recent ATLAS and CMS data. Such an effect can reduce the role of stop mixing.Comment: 26 pages, 3 figures; published in JHE

Review of LHC experimental results on low mass bosons in multi Higgs models

A number of searches at the LHC looking for low mass ($2m_{\mu} - 62\ \mathrm{GeV}$) bosons in$\sqrt{s} = 8\ \mathrm{TeV}$ data have recently been published. We summarise the most pertinent ones, and look at how their limits affect a variety of supersymmetric and non-supersymmetric models which can give rise to such light bosons: the 2HDM (Types I and II), the NMSSM, and the nMSSM.Comment: 29 pages, 14 figures, 4 tables. Updated title, abstract, and citation

Peccei-Quinn invariant extension of the NMSSM

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.Comment: 22 pages, 3 figures; published versio