Triviality bound on lightest Higgs mass in next to minimal supersymmetric model

We study the implication of triviality on Higgs sector in next to minimal supersymmetric model (NMSSM) using variational field theory. It is shown that the mass of the lightest Higgs boson in NMSSM has an upper bound ∼10M _W which is of the same order as that in the standard model.     

Radiative corrections to Higgs boson masses in supersymmetric models

The effect of radiative corrections on the Higgs masses and couplings in supersymmetric models is summarized. Radiative corrections in both the minimal and nonminimal models are discussed. It is pointed out that large singlet Higgs vacuum expectation values are screened out from the radiative corrections to the lightest Higgs mass in nonminimal models. In supersymmetric models the crucial mass limit for the Higgs search may be around 150 GeV.     

Radiative corrections to Higgs boson masses in supersymmetric models

The effect of radiative corrections on the Higgs masses and couplings in supersymmetric models is summarized. Radiative corrections in both the minimal and nonminimal models are discussed. It is pointed out that large singlet Higgs vacuum expectation values are screened out from the radiative corrections to the lightest Higgs mass in nonminimal models. In supersymmetric models the crucial mass limit for the Higgs search may be around 150 GeV.     

Higgs bosons in supersymmetric models (I)

We describe the properties of Higgs bosons in a class of supersymmetric theories. We consider models in which the low-energy sector contains two weak complex doublets and perhaps one complex gauge-singlet Higgs field. Supersymmetry is assumed to be either softly or spontaneously broken, thereby imposing a number of restrictions on the Higgs boson parameters. We elucidate the Higgs boson masses and present Feynman rules for their couplings to the gauge bosons, fermions and scalars of the theory. We also present Feynman rules for vertices which are related by supersymmetry to the above couplings. Exact analytic expressions are given in two useful limits — one corresponding to the absence of the gauge-singlet Higgs field and the other corresponding to the absence of a supersymmetric Higgs mass term.     

All possible lightest supersymmetric particles in R-parity violating minimal supergravity models

We investigate, which lightest supersymmetric particles can be obtained via a non-vanishing lepton- or baryon-number violating operator at the grand unification scale within the R-parity violating minimal supergravity model. We employ the full one-loop renormalization group equations. We take into account restrictions from the anomalous magnetic moment of the muon and b→sγ$b\to s\gamma$, as well as collider constraints from LEP and the Tevatron. We also consider simple deformations of minimal supergravity models.     

Precise prediction for the mass of the lightest Higgs boson in the MSSM

The leading diagrammatic two-loop corrections are incorporated into the prediction for the mass of the lightest Higgs boson, m_h, in the Minimal Supersymmetric Standard Model (MSSM). The results, containing the complete diagrammatic one-loop corrections, the new two-loop result and refinement terms incorporating leading electroweak two-loop and higher-order QCD contributions, are discussed and compared with results obtained by renormalization group calculations. Good agreement is found in the case of vanishing mixing in the scalar quark sector, while sizable deviations occur if squark mixing is taken into account.     

Effective two Higgs doublets in nonminimal supersymmetric models

The Higgs sectors of supersymmetric extensions of the Standard Model have two doublets in the minimal version (MSSM), and two doublets plus a singlet in two others: with (UMSSM) and without (NMSSM) an extra U(1)′. A very concise comparison of these three models is possible if we assume that the singlet has a somewhat larger breaking scale compared to the electroweak scale. In that case, the UMSSM and the NMSSM become effectively two-Higgs-doublet models (THDM), like the MSSM. In this approach the well-known upper mass bounds on the lightest CP-even neutral Higgs boson can be derived in a very simple and transparent way.     

Higgs masses in the standard,multi-Higgs and supersymmetric models

Theoretical constraints and limits on the masses of Higgs scalars in the standard electroweak model, in electroweak models with additional Higgs doublets and in various supersymmetric models are presented. In the standard model, the lower limit on the Higgs mass, based on vacuum stability arguments, is reviewed in detail, as are “upper limits” based on perturbative constraints. In most grand unified and all supersymmetric models, however, at least two doublets are needed. The masses of the various Higgs scalars in the two-doublet model are discussed and constraints on their masses are found, including the generalization of the above limits. The results are then generalized to models with more than two doublets. Finally, recent attempts at constructing models with low-energy supersymmetry are reviewed and it is shown that in many models, fairly stringent tree-level mass relations among the Higgs scalars can be found. These relations are interesting in that they do not refer to the supersymmetric partners of ordinary particles, and they are most restrictive in models in which the supersymmetry is explicitly broken, i.e., via arbitrary mass terms.     

Approximating the radiatively corrected Higgs mass in the minimal supersymmetric model

To obtain the most accurate predictions for the Higgs masses in the minimal supersymmetric model (MSSM), one should compute the full set of one-loop radiative corrections, resum the large logarithms to all orders, and add the dominant two-loop effects. A complete computation following this procedure yields a complex set of formulae which must be analyzed numerically. We discuss a very simple approximation scheme which includes the most important terms from each of the three components mentioned above. We estimate that the Higgs masses computed using our scheme lie within 2 GeV of their theoretically predicted values over a very large fraction of MSSM parameter space.     

TheR-symmetry violation inN=2 supersymmetric models and the properties of lightest SUSY particle

The present paper discusses the spontaneousR-symmetry violation in theN=2 SUSYSU(4)×U(1) model [1] with soft SUSY breaking terms preserving finiteness. In particular, the mechanism producing a light photino (as a probable candidate for LSP) of a mass of up to some GeV is suggested. InR-odd versions of this model the mechanism of enhancement of the photino decay is discussed.     

Perhaps scalar neutrinos are the lightest supersymmetric partners

We consider the possibility that the scalar partners of the neutrinos $\text{(}\text{v}\text{)}$ are the least massive supersymmetric partners, and show that this alternative is compatible with cosmological constraints, which put a significant lower bound on photino masses but not on $\text{v}$ masses. Various consequences are examined: the photon counting rate for $\text{e}{}^{\mathrm{+}}\text{e}{}^{\mathrm{-}}\text{→γ}\text{v}$$\text{v}\text{?}\text{?}$ may be large; the rate for $\text{e}{}^{\mathrm{+}}\text{e}{}^{\mathrm{-}}\text{→}\text{W}{}^{\mathrm{+}}\text{a}\text{W}{}^{\mathrm{-}}$ by $\text{v}$ exchange is enhaced; Z⁰→ increases Γ(Z⁰) by about 0.25 GeV; $\text{W}{}^{\mathrm{\pm }}\text{→}\text{?}{}^{\mathrm{+-}}\text{v}$ may be enhanced; the decay $\text{τ→}\text{v}{}_{\mathrm{\tau }}\text{?}{}_{\mathrm{?}}$$\text{v}\text{?}\text{?}$ may be detectable; there can be additional contributions to the rare decay $\text{K}{}^{\mathrm{+}}\text{→π}{}^{\mathrm{+}}\text{v}$$\text{v}\text{?}\text{?}$; restrictions on gluino masses, which depend on photinos interacting before they decay, have to be re-examined; scalar neutrinos have suitable characteristics as candidates for dark matter in the universe. We discuss one currently fashionable class of models that can predicr a light $\text{v}$.