John F. Gunion

Higgs Bosons in Supersymmetric Models. 1.

Abstract 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.

The CP conserving two Higgs doublet model: The Approach to the decoupling limit

A CP-even neutral Higgs boson with standard-model-like couplings may be the lightest scalar of a two-Higgs-doublet model. We study the decoupling limit of the most general CP-conserving two-Higgs-doublet model, where the mass of the lightest Higgs scalar is significantly smaller than the masses of the other Higgs bosons of the model. In this case, the properties of the lightest Higgs boson are nearly indistinguishable from those of the standard model Higgs boson. The first nontrivial corrections to Higgs boson couplings in the approach to the decoupling limit are also evaluated. The importance of detecting such deviations in precision Higgs boson measurements at future colliders is emphasized. We also clarify the case in which a neutral Higgs boson can possess standard-model-like couplings in a regime where the decoupling limit does not apply. The two-Higgs-doublet sector of the minimal supersymmetric model illustrates many of the above features.

NMHDECAY: A Fortran code for the Higgs masses, couplings and decay widths in the NMSSM

The Fortran code NMHDECAY computes the masses, couplings and decay widths of all Higgs bosons of the NMSSM in terms of its parameters at the electroweak (or Susy breaking) scale: the Yukawa couplings λ and κ, the soft trilinear terms Aλ and Aκ, and tan β and μeff = λ . The computation of the spectrum includes leading two loop terms, electroweak corrections and propagator corrections. The computation of the decay widths is carried out as in HDECAY, but (for the moment) without three body decays. Each point in parameter space is checked against negative Higgs bosons searches at LEP, including unconventional channels relevant for the NMSSM. One version of the program uses generalized SLHA conventions for input and output.

Escaping the large fine tuning and little hierarchy problems in the next to minimal supersymmetric model and h ---> aa decays

We demonstrate that the next to minimal supersymmetric model can have small fine-tuning and modest top-squark mass while still evading all experimental constraints. For small tan(beta (large tan(beta), the relevant scenarios are such that there is always (often) a standard-model-like Higgs boson that decays to two lighter--possibly much lighter--Higgs pseudoscalars.

Higgs bosons in supersymmetric models (II). Implications for phenomenology

Abstract We discuss a wide range of phenomenological issues involving the production and decay of Higgs bosons. We focus on a minimal two-doublet supersymmetry model with soft supersymmetry breaking.

Benchmark models, planes, lines and points for future SUSY searches at the LHC

We define benchmark models for SUSY searches at the LHC, including the CMSSM, NUHM, mGMSB, mAMSB, MM-AMSB and p19MSSM, as well as models with R-parity violation and the NMSSM. Within the parameter spaces of these models, we propose benchmark subspaces, including planes, lines and points along them. The planes may be useful for presenting results of the experimental searches in different SUSY scenarios, while the specific benchmark points may serve for more detailed detector performance tests and comparisons. We also describe algorithms for defining suitable benchmark points along the proposed lines in the parameter spaces, and we define a few benchmark points motivated by recent fits to existing experimental data.

Charge / Color Breaking Minima and a-Parameter Bounds in Supersymmetric Models

In supersymmetric models, the requirement that the global potential minimum not violate color and/or electric charge invariance implies restrictions on the parameters of the model. We reassess and improve upon constraints on the A parameter that have been obtained previously in the literature. In particular, we demonstrate that no universally applicable bound which is either necessary or sufficient can be given.

The constrained NMSSM and Higgs near 125 GeV

Abstract We assess the extent to which various constrained versions of the NMSSM are able to describe the recent hints of a Higgs signal at the LHC corresponding to a Higgs mass in the range 123–128 GeV.

Light neutralino dark matter in the next-to-minimal supersymmetric standard model

Neutralino dark matter is generally assumed to be relatively heavy, with a mass near the electroweak scale. This does not necessarily need to be the case, however. In the Next-to-Minimal Supersymmetric Standard Model (NMSSM) and other supersymmetric models with an extended Higgs sector, a very light CP-odd Higgs boson can naturally arise making it possible for a very light neutralino to annihilate efficiently enough to avoid being overproduced in the early Universe. In this article, we explore the characteristics of a supersymmetric model needed to include a very light neutralino, 100 MeV

Status of invisible Higgs decays

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