Soft Supersymmetry Breaking Scale Research Articles

Seesaw mechanism in the R-parity-violating supersymmetric standard model with the gauged flavor U(1)X symmetry

Abstract We study the seesaw mechanism in the supersymmetric standard model (SSM) with the ${\mathbb {Z}}_3$ symmetry called matter triality (M3). The Abelian discrete symmetry prohibits the baryon number violation operators at the (non-)renormalizable level, which ensures proton longevity. The cubic coupling by right-handed neutrinos generates the Majorana mass term after the right-handed sneutrinos develop into the vacuum expectation values. Due to the R-parity violation, the active neutrino masses can be generated not only from the mixings with the right-handed neutrinos but also from those with the minimal SSM neutralinos. We propose a model where M3 is embedded in the gauged flavor symmetry. The flavor charges are constrained by the anomaly cancellation conditions and the requirements to realize the fermion masses and mixing angles in the quark and lepton sectors. We analyze the assignments of the flavor charge, and show that the sterile neutrino mass is allowed to be below the soft supersymmetry-breaking scale, which is constrained by the half-lifetime of the neutrinoless double beta decay.

Constraining Affleck-Dine leptogenesis after thermal inflation

Affleck-Dine leptogenesis after thermal inflation along the LHu direction requires mL2+mHu2 < 0 up to the AD scale (|L|≃|Hu|∼ 109 GeV). We renormalised this condition from the AD scale to the soft supersymmetry breaking scale by solving the renormalisation group equations perturbatively in the Yukawa couplings to obtain a semi-analytic constraint on the soft supersymmetry breaking parameters, which is much stronger than the tree-level result. We also used a fully numerical method to renormalise the baryogenesis condition and constrained the Minimal Supersymmetric Cosmological Model using the resulting baryogenesis condition and other constraints, specifically, electroweak symmetry breaking, the observed Higgs mass, and the axion and axino dark matter abundance.

De Sitter vacuum fromR2supergravity

We propose a supergravity model with a constrained curvature multiplet, which realizes the Starobinsky inflation and the de Sitter vacuum in the present universe simultaneously. Surprisingly, at the vacuum, the soft supersymmetry breaking scale for minimal supersymmetric standard model sector becomes the TeV scale, however, the gravitino mass scale becomes much higher than that of soft supersymmetry breaking. Such a hierarchical structure, which naturally avoids the gravitino problem, appears without introducing a new scale other than inflation scale.

Axion dark matter with high-scale inflation

We show that supersymmetric axion models breaking the PQ symmetry by the interplay of non-renormalizable supersymmetric terms and soft supersymmetry breaking terms provide a natural framework not only for generating the axion scale from soft supersymmetry breaking scale m3/2 but also for enhancing it during inflation by factor of order HI/m3/2 where HI≃1014 GeV according to the recent BICEP2 result. In this scheme, the PQ symmetry can stay broken throughout the whole history of the Universe if the reheat temperature is below 1010 GeV, or m3/2 when the PQ fields couple strongly to thermal (Standard Model) particles. It is also shown that parametric resonance during preheating is not effective enough to induce non-thermal PQ symmetry restoration. As a consequence, axion models with the QCD anomaly NDW>1 can be made free from the domain wall problem while the axion isocurvature perturbation is suppressed sufficiently for the axion scale during inflation larger than about MP(Ωah2/0.12)1/2(Fa/1012 GeV)0.6 GeV.

Minimal fine tuning in supersymmetric Higgs inflation

We investigate characteristic features of realistic parameter choice for primordial inflation with supersymmetric Higgs inflaton as an example of particle physics inflation model. We discuss constraints from observational results and analyze the degree of fine tuning needed to induce slow-roll inflation for wide range of soft supersymmetry breaking scale. The observed amplitude of density fluctuations implies that the minimal fine tuning for the combined electroweak scale and inflaton flatness predicts the spectral index of 0.950--0.965, which includes the central value from observational data.

Textures and semi-local strings in supersymmetric hybrid inflation

Global topological defects may account for the large cold spot observed in the cosmicmicrowave background. We explore possibilities for constructing models of supersymmetricF-term hybrid inflation, where the waterfall fields are globallySU(2)-symmetric. In contrastto the case where SU(2) is gauged, there arise Goldstone bosons and additional moduli, which are lifted only bymasses of soft supersymmetry breaking scale. The model predicts the existence of globaltextures, which can become semi-local strings if the waterfall fields are gauged underU(1)X. Gravitino overproduction can be avoided if reheating proceeds via the lightSU(2)-modes or right-handed sneutrinos. For values of the inflaton–waterfall coupling , the symmetry breaking scale imposed by normalization of the power spectrumgenerated from inflation coincides with the energy scale required to explain the mostprominent of the cold spots. In this case, the spectrum of density fluctuations isclose to scale invariant, which can be reconciled with measurements of the powerspectrum by the inclusion of the sub-dominant component due to the topologicaldefects.

Effective messenger sector from dynamical supersymmetry breaking

In the framework of the dynamical supersymmetry breaking we construct the messenger sector as the effective theory of supersymmetry breaking sector, which is based on the SU(3) × SU(2) model of Affleck, Dine and Seiberg. In our model, messenger superfields with the nonrenormalizable interaction are contained. By minimizing the scalar potential, we show that the supersymmetry breaking can be communicated to the visible sector without breaking QCD color. In this model there appear various scales. Supersymmetry breaking scale turns out to be the intermediate scale (∼ 10 10 GeV) between the GUT scale and the soft supersymmetry breaking scale.

Renormalization-group analysis of the Higgs sector in the minimal supersymmetric standard model

We examine the particle spectra of the Higgs sector in the minimal supersymmetric extension of the standard model using the one-loop renormalization group evolution of the scalar self-couplings. We treat the general case in which there are two light Higgs doublets below the soft supersymmetry breaking scale M SUSY. The model with only one light CP-even neutral scalar particle appears as a particular limiting case in our analysis. Using theoretical and experimental results, we obtain upper and lower bounds on the neutral CP-even and charged Higgs mass spectrum. The triviality bounds on the top and Higgs masses are also analyzed, yielding constraints on the range of mass parameters consistent with possible grand unification scenarios. We obtain that for an effective cutoff scale Λ ⋍ 10 16 GeV (10 10 Gev) , a soft supersymmetry breaking scale M SUSY ⋍ 1 TeV and a CP-odd state mass m A ⋍ 40 GeV , the lightest CP-even state mass is bounded to be m h ⩽ 52 GeV (60 GeV). In addition, for the same values of Λ and M SUSY, and for m A ⩾ M Z, the tree-level relation m h ⩽ m A is fulfilled. Our analysis indicates that, in the simplest grand unification scenarios with M GUT ⋍ 10 16 GeV and M SUSY ⋍ 1 TeV , the decay mode h → AA is only allowed if m A ⩽ 26 GeV.

Baryogenesis constraints on the minimal supersymmetric model

The requirement that the vacuum expectation values of Higgs fields immediately after the phase transition be large enough imposes constraints upon the parameters of the minimal supersymmetric model. In particular, one obtains the upper bounds on the lighter CP-even Higgs mass and the soft supersymmetry breaking scale for different values of the top quark mass.

Dynamical symmetry breaking and the top quark mass in the minimal supersymmetric standard model

The minimal supersymmetric extension of the standard model is studied, when the electroweak symmetry breakdown relies on the formation of condensates involving the third generation of quarks and their supersymmetric partners. The top quark mass is obtained as a function of the compositeness scale Λ and the soft supersymmetry breaking scale, Δ S . The dependence of the top quark mass on the ration of the Higgs vacuum expectation values, as well as a function of the lightest Higgs mass, is analyzed. We show that, when Λ ≅ 10 16 GeV, the characteristics top quark mass in this model is 140 GeV ⩽ m t ⩽ 195 Gev, a prediction that is only slightly dependent on the value of Δ S .

Nonrenormalizable interactions from supergravity, quantum corrections and effective low energy theories

We investigate the effects of quantum corrections involving nonrenormalizable interactions suppressed by powers of the Planck scale Mp in supersymmetric theories. Assuming a cutoff of O(Mp) and taking soft supersymmetry breaking into account, we derive the corresponding power counting rules with the help of superspace methods. We find that supersymmetric mass terms proportional to the soft supersymmetry breaking scale m and one point functions for gauge singlet fields proportional to mMp can be generated radiatively.