Metastable SUSY Breaking - Predicting the Fate of the Universe
Joerg Jaeckel
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12 pages, 2 figures. Contribution to the proceedings of the "Strong and Electroweak Matter 2008 (SEWM 08)" conference, Amsterdam, the Netherlands, 26-29 August 2008
The possibility that supersymmetry (SUSY) could be broken in a metastable vacuum has recently attracted renewed interest. In these proceedings we will argue that metastability is an attractive and testable scenario. The recent developments were triggered by the presentation of a simple and calculable model of metastable SUSY breaking by Intriligator, Seiberg and Shih (ISS), which we will briefly review. One of the main questions raised by metastability is, why did the universe end up in this vacuum. Using the ISS model as an example we will argue that in a large class of models the universe is automatically driven into the metastable state during the early hot phase and gets trapped there. This makes metastability a natural option from the cosmological point of view. However, it may be more than that. The phenomenologically required gaugino masses require the breaking of R-symmetry. However, in scenarios with a low supersymmetry breaking scale, e.g., gauge mediation a powerful theorem due to Nelson and Seiberg places this at odds with supersymmetry breaking in a truely stable state and metstability becomes (nearly) inevitable. Turning around one can now experimentally test whether gauge mediation is realised in nature thereby automatically testing the possibility of a metastability of the vacuum. Indeed, already the LHC may give us crucial information about the stability of the vacuum.
A fresh analysis of Left right symmetric supersymmetric models in the generic case where the scale of right handed symmetry breaking $M_R >> M_{SUSY}\sim M_W$ is presented. We conclude that the low energy effective theory for such models is essentially the MSSM with R parity (and therefore B,L symmetry) but the spectrum includes heavy conjugate neutrino supermultiplets that permit a seesaw mechanism and several characteristic charged supermultiplets over and above those of the MSSM.
We introduce fully SGUTs, SUSY grand unified theories that, upon symmetry breaking through the Higgs mechanism, decompose into a visible sector and an extra sector where the dynamics of the extra sector gauge group is responsible for SUSY breaking. Fully SGUTs thus have the important feature that all gauge groups of the visible sector and the extra sector unify into a simple gauge group at the SGUT scale, therefore generalizing the successful MSSM gauge coupling unification to all the gauge couplings of the theory. By focusing on the ISS SUSY-breaking mechanism in the extra sector, we show tha…
Recently Murayama and Nomura proposed a simple scheme to construct the gauge mediation models, using metastable supersymmetry breaking vacua. It has a possibility to predict the ultra light gravitino mass m_{3/2} \lesssim 16 eV, while such a light gravitino may destabilize the metastable vacua. We investigate stability of the metastable vacuum of their model. The transition rate from the false vacuum to true ones is evaluated by numerical calculation, including the Coleman-Weinberg potential destabilizing the metastable vacuum. It is found that when the messenger sector is minimal, stability o…
We present the mechanism of the dynamical supersymmetry (SUSY) breaking at the metastable vacuum in the N=1 U(N) SUSY gauge theory with adjoint superfields. The dynamical SUSY breaking is triggered by the non-vanishing D-term coupled to the observable sector, and is realized by the self-consistent Hartree-Fock approximation of the NJL type while it eventually brings us the non-vanishing F-term as well. We numerically check the local stability of our metastable vacuum.
We construct an N=2 supersymmetric generalization of the N=1 supercurrent formalism of Komargodski and Seiberg (KS) and use it to show that N=2 theories with linear superconformal anomalies cannot break SUSY under certain broad assumptions. This result suggests that there are no metastable SUSY breaking vacua in a large class of theories that includes N=2 Super Yang-Mills (SYM).
We show that in (anomalous) U(1) gauge theories with the Fayet-Iliopoulos (FI) term and with generic interactions there are meta-stable vacua in which supersymmetry (SUSY) is spontaneously broken even without U(1)_R symmetry and various hierarchical structures, for example, Yukawa hierarchy, can be explained by the smallness of the FI parameter. When we introduce generic interactions, i.e., all interactions including higher dimensional interactions which are allowed by the symmetry of the theory with O(1) coefficients, various scales can be determined by the symmetry (U(1) charges of the intro…
Supersymmetry breaking in a metastable vacuum is re-examined in a cosmological context. It is shown that thermal effects generically drive the Universe to the metastable minimum even if it begins in the supersymmetry-preserving one. This is a generic feature of the ISS models of metastable supersymmetry breaking due to the fact that SUSY preserving vacua contain fewer light degrees of freedom than the metastable ground state at the origin. These models of metastable SUSY breaking are thus placed on an equal footing with the more usual dynamical SUSY breaking scenarios.
We construct a model of direct gauge mediation of metastable SUSY breaking by simply deforming the Intriligator, Seiberg and Shih model in terms of a dual meson superpotential mass term. No extra matter field is introduced. The deformation explicitly breaks a U(1)_R symmetry and a pseudo moduli have a nonzero VEV at one-loop. Our metastable SUSY breaking vacuum turns out to be sufficiently long-lived. By gauging a subgroup of flavor symmetry, our model can directly couple to the standard model, which leads to nonvanishing gaugino mass generation. It is also shown that our model can evade the L…
It has long been known that the broken supersymmetric (susy) phase of the singlet extended susy higgs model (SESHM) is at best metastable and the ground states of the model have vanishing vacuum energy and are exactly supersymmetric. If the SESHM is confirmed at the Large Hadron Collider (LHC), the numerical values of the parameters of the model have a bearing on key properties of the susy phase and might provide an estimate of the remaining time before a possible decay of our false vacuum. We provide some analysis of the model including a treatment of phases in the potential and soft higgs ma…
We propose a new chiral model of metastable supersymmetry breaking in the conformal window via chiral/nonchiral Seiberg duality, which is focused on Spin(7)/SU(N_f-4) duality in this letter. Following the approach of Intriligator-Seiberg-Shih model, a small mass perturbation in the nonchiral theory leads to supersymmetry breaking by rank condition in the chiral dual description.
We propose a model of metastable dynamical supersymmetry breaking in which all scales are generated dynamically. Our construction is a simple variant of the Intriligator-Seiberg-Shih model, with quark masses induced by renormalizable couplings to an auxiliary supersymmetric QCD sector. Since all scales arise from dimensional transmutation, the model has no fundamental dimensionful parameters. It also does not rely on higher-dimensional operators.
We study gauge mediation in a wide class of O'Raifeartaigh type models where supersymmetry breaking metastable vacuum is created by gravity and/or quantum corrections. We examine their thermal evolution in the early universe and the conditions under which the susy breaking vacuum can be selected. It is demonstrated that thermalization typically makes the metastable supersymmetry breaking cosmologically disfavoured but this is not always the case. Initial conditions with the spurion displaced from the symmetric thermal minimum and a small coupling to the messenger sector can result in the reali…
We study N=1 global and local supersymmetric theories with a continuous global $U(1)_R$ symmetry as models of dynamical supersymmetry (SUSY) breaking. We introduce explicit R-symmetry breaking terms into such models, in particular a generalized O'Raifeartaigh model. Such explicit R-symmetry breaking terms can lead to a SUSY preserving minimum. We classify explicit R-symmetry breaking terms by the structure of newly appeared SUSY stationary points as a consequence of the R-breaking effect, which could make the SUSY breaking vacuum metastable. We show that the R-breaking terms are basically divi…
We propose a direct gauge mediation model based on an uplifted metastable SUSY breaking coupled to supergravity. A constant superpotential plays an essential role to fix the moduli as well as breaking SUSY and R-symmetry and the cancellation of the cosmological constant. Gaugino masses are generated at leading order of SUSY breaking scale, and comparable to the sfermion masses as in the ordinary gauge mediation. Landau pole problem for QCD coupling can be easily solved since more than half of messengers become superheavy, which are heavier than the GUT scale.
We construct a supersymmetric version of the Standard Model which contains a long-lived metastable vacuum. In this vacuum supersymmetry is broken and the electroweak symmetry is Higgsed, and we identify it with the physical ground state of the Standard Model. In our approach the metastable supersymmetry breaking (MSB) occurs directly in the SU(2)_L x U(1)_Y sector of the Standard Model; it does not require a separate MSB sector and in this way it departs from the usual lore. There is a direct link between the electroweak symmetry breaking and the supersymmetry breaking in our model, both effec…
We discuss the coupling of heavy moduli fields to light fields when the dynamics of the latter, absent such couplings, yields metastable vacua. We show that the survival of the vacuum structure of the local model depends nontrivially on the cross-couplings of the two sectors. In particular we find that for "local" models (such as those realized by D-branes in type II string theories) with metastable vacua breaking supersymmetry via F-terms, cross-coupling of the two sectors at an intermediate scale can push the metastable vacuum outside of the regime of the effective field theory. We parametri…
We carry out a model-independent EFT method study on the vacuum statistics of general F-term SUSY breaking models. Assuming a smooth distribution of Lagrangian parameters, SUSY breaking vacua are rare in global SUSY models with a canonical Kähler potential, and have a peaked distribution near the cut-off of the SUSY breaking scale in both global SUSY and SUGRA models with a general Kähler potential. After including different mass scales in the Lagrangian, we compare the total number of SUSY and non-SUSY vacua and estimate quantitatively the rareness of SUSY breaking. The EFT method provides a …
Supersymmetry breaking in a metastable vacuum allows one to build simple and concrete models of gauge mediation. Generation of gaugino masses requires that R-symmetry be broken in this vacuum. In general, there are two possible ways to break R-symmetry, explicitly or spontaneously. We find that the MSSM phenomenology depends crucially on how this breaking occurs in the Hidden Sector. Explicit R-symmetry breaking models can lead to fairly standard gauge mediation, but we argue that in the context of ISS-type models this only makes sense if B=0 at the mediation scale, which leads to high tan(bet…
The smallest classically stable Q-balls are, in fact, generically metastable: in quantum theory they decay into free particles via collective tunneling. We derive general semiclassical method to calculate the rate of this process in the entire kinematical region of Q-ball metastability. Our method uses Euclidean field-theoretical solutions resembling the Coleman's bounce and fluctuations around them. As an application of the method, we numerically compute the decay rate to the leading semiclassical order in a particular one-field model. We shortly discuss cosmological implications of metastabl…
We consider the role of supersymmetric flat directions in reheating the Universe after inflation. One or more flat directions can develop large vevs during inflation, which can potentially affect reheating by slowing down scattering processes among inflaton decay products or by coming to dominate the energy density of the Universe. Both effects occur only if flat directions are sufficiently long-lived. The computation of their perturbative decay rate, and a simple estimate of their nonperturbative decay have led to the conclusion that this is indeed the case. In contrast, we show that flat dir…
Supersymmetric models with a small neutralino-chargino mass difference, and as a result metastable charginos, have been a popular topic of investigation in collider phenomenology, e.g. in anomaly-mediated models of supersymmetry breaking. Recently, the absence of any supersymmetric signal at the 8 TeV LHC data has led to significant interest in the so-called Natural SUSY models with light higgsinos. These models also have a naturally small neutralino-chargino mass difference. However, we show here that when relevant indirect constraints from results at the LHC and elsewhere are applied, this p…
The breaking of $U(1)_R$ symmetry plays a crucial role in modeling the breaking of supersymmetry (SUSY). In the models that possess both SUSY preserving and SUSY breaking vacua, tube-like cosmic strings called R-tubes, whose surfaces are constituted by domain walls interpolating a false and a true vacuum with some winding numbers, can exist. Their (in)stability can strongly constrain SUSY breaking models theirselves. In the present study, we investigate the dynamical (in)stability of two colliding metastable tube-like strings by field-theoretic simulations. From them, we find that the strings …
We review the emergence and fate of goldstinos in different frameworks. First, we consider a super-Higgs mechanism when supersymmetry breaking is induced by neither an F-term nor a D-term but related to a more general stress energy-momentum tensor. This allows us to build a novel Lagrangian that describes the propagation of a spin-3/2 state in a fluid. Then we briefly review the ubiquitous pseudo-goldstinos when breaking supersymmetry in an extra dimension. We remind that the fermion (gravitino or gaugino) soft masses can be tuned to be of Dirac-type. Finally, we briefly connect the latter to …
I put metastable supersymmetry breaking in a cosmological context. I argue that under reasonable assumptions, the cooling down early Universe favors metastable SUSY-breaking vacua over the stable supersymmetric vacua. To illustrate the general argument, I analyze the early-Universe history of the Intriligator-Seiberg-Shih model.
We investigate the short distance fate of distinct classes of not asymptotically free supersymmetric gauge theories. Examples include super QCD with two adjoint fields and generalised superpotentials, gauge theories without superpotentials and with two types of matter representation and semi-simple gauge theories such as quivers. We show that for the aforementioned theories asymptotic safety is nonperturbatively compatible with all known constraints.
Current attempts to understand supersymmetry (susy) breaking are focused on the idea that we are not in the ground state of the universe but, instead, in a metastable state that will ultimately decay to an exactly susy ground state. It is interesting to ask how experiments at the Large Hadron Collider (LHC) will shed light on the properties of this future supersymmetric universe. In particular we ask how we can determine whether this final state has the possibility of supporting atoms and molecules in a susy background.
We show how gauged flavour breaking and N = 1 supersymmetry breaking can be dynamically aligned to produce natural models. Supersymmetry is broken in a metastable vacuum, while a weakly gauged flavour symmetry is identified with an SU(3)_F subgroup of the global symmetry of the SQCD model. We find that alignment can easily occur either through strongly coupled flavour models, with SQCD bound states playing the role of flavons, or entirely weakly coupled and renormalizable models with elementary SU(3)_F adjoint flavons. In both cases it is essential that the SU(3)_F breaking, and hence all the …
I review theoretical developments of the last year or so in nonperturbative supersymmetry. Topics: (i) Metastable vacua at strong coupling; (ii) Non-Abelian flux tubes, confined monopoles; (iii) One step beyond Seiberg's duality; (iv) Planar equivalence; (v) Multileg/multiloop amplitudes; (vi) N= (2,0) sigma model on the string worldsheet.
A model of generalised hybrid inflation in a supersymmetric QCD theory is proposed whose parameters are the gauge coupling and quark masses. Its gravitational coupling to another SQCD sector induces a metastable supersymmetry breaking vacuum of the ISS type as ISS quarks become massive at the end of inflation. Using a known mechanism with a gravitational breaking of the baryon number and the gauging of flavour symmetries, we find that gauge mediation of supersymmetry breaking is compatible with the dynamics of the inflation sector. Reheating proceeds via the thermalization of the ISS messenger…
It was recently shown in hep-th/0610334 that in the context of the ISS models with a metastable supersymmetry breaking vacuum, thermal effects generically drive the Universe to the metastable vacuum even if it began after inflation in the supersymmetry-preserving one. We continue this programme and specifically take into account two new effects. First is the effect of the mass-gap of the gauge degrees of freedom in the confining supersymmetry preserving vacua, and second, is the effect of the back reaction of the MSSM sector on the SUSY breaking ISS sector. It is shown that, even though the ma…
Anomalously small gaugino masses are a common feature of various models of direct gauge mediation. This problem is closely related to the vacuum structure of the theory. In this paper we show that massive SQCD can have SUSY-breaking vacua which are qualitatively different from the ISS vacuum. These novel vacua are metastable with respect to decay to the ISS vacuum. We demonstrate the possibility of addressing the gaugino mass problem in this framework. We study the properties of these vacua and construct an example of a model of direct gauge mediation.
We study the direct mediation of metastable supersymmetry breaking by a Φ^2-deformation to the ISS model and extend it by splitting both TrΦand TrΦ^2 terms in the superpotential and gauging the flavor symmetry. We find that with such an extension the enough long-lived metastable vacua can be obtained and the proper gaugino masses can be generated. Also, this allows for constructing a kind of models which can avoid the Landau pole problem. Especially, in our metastable vacua there exist a large region for the parameter m_3 which can satisfy the phenomenology requirements and allow for a low SUS…
We examine a metastable $\mathcal{N}=1$ Macroscopic SO(N) SQCD model of Intriligator, Seiberg and Shih (ISS). We introduce various baryon and meson deformations, including multitrace operators and explore embedding an SO(10) parent of the standard model into two weakly gauged flavour sectors. Direct fundamental messengers and the symmetric pseudo-modulus messenger mediate SUSY breaking to the MSSM. Gaugino and sfermion masses are computed and compared for each deformation type. We also explore reducing the rank of the magnetic quark matrix of the ISS model and find an additional fundamental me…
We search for viable models of direct gauge mediation, where the SUSY-breaking sector is (generalized) SQCD, which has cosmologically favorable uplifted vacua even when the reheating temperature is well above the messenger scale. This requires a relatively large tadpole term in the scalar potential for the spurion field X and, consequently, we argue that pure (deformed) SQCD is not a viable model. On the other hand, in SQCD with an adjoint, which is natural e.g. in string theory, assuming an appropriate sign in the Kahler potential for X, such metastable vacua are possible.
We have recently suggested that tiny black holes can act as nucleation seeds for the decay of the metastable Higgs vacuum. Previous results applied only to the nucleation of thin-wall bubbles, and covered a very small region of parameter space. This paper considers bubbles of arbitrary profile and reaches the same conclusion: black holes seed rapid vacuum decay. Seeded and unseeded nucleation rates are compared, and the gravitational back reaction of the bubbles is taken into account. The evolution of the bubble interior is described for the unseeded nucleation. Results are presented for the r…
This talk reviews our recent work showing how tiny black holes can act as nucleation sites for the decay of the metastable Higgs vacuum. We start by discussing the formation of thin wall bubbles of true vacuum inside a false vacuum, and show how adding a black hole lowers the action of the Euclidean tunneling solution, thus strongly enhancing the probability of vacuum decay. We then review numerical results for the Higgs vacuum showing that the decay rate is even higher for these "thick wall" bubbles. The results imply either tiny black holes are not a component of our universe, or BSM correct…
We study the formation of Q-balls which are made of flat directions that appear in the supersymmetric extension of the standard model in the context of gravity-mediated supersymmetry breaking. The full non-linear calculations for the dynamics of the complex scalar field are made. Since the scalar potential in this model is flatter than ϕ^2, we have found that fluctuations develop and go non-linear to form non-topological solitons, Q-balls. The size of a Q-ball is determined by the most amplified mode, which is completely determined by the model parameters. On the other hand, the charge of Q-ba…
Our electroweak vacuum may be metastable in light of the current experimental data of the Higgs/top quark mass. If this is really the case, high-scale inflation models require a stabilization mechanism of our vacuum during inflation. A possible candidate is the Higgs-inflaton/-curvature coupling because it induces an additional mass term to the Higgs during the slow roll regime. However, after the inflation, the additional mass term oscillates, and it can potentially destabilize our electroweak vacuum via production of large Higgs fluctuations during the inflaton oscillation era. In this paper…
In split-supersymmetry (split-SUSY), gluino is a metastable particle and thus can freeze out in the early universe. The late decay of such a long-life gluino into the lightest supersymmetric particle (LSP) may provide much of the cosmic dark matter content. In this work, assuming the LSP is gravitino produced from the late decay of the metastable gluino, we examine the WMAP dark matter constraints on the gluino mass. We find that to provide the full abundance of dark matter, the gluino must be heavier than about 14 TeV and thus not accessible at the CERN Large Hadron Collider (LHC).
We study the effective potential and the Renormalization Group(RG) improvement to the effective potential of Higgs boson in a singlet-doublet fermion dark matter extension of the Standard Model(SM), and in general singlet-doublet fermion extension models with several copies of doublet fermions or singlet fermions. We study the stability of the electroweak vacuum with the RG improved effective potential in these models beyond the SM. We study the decay of the electroweak vacuum using the RG improved effective potential in these models beyond the SM. In this study we consider the quantum correct…
Low energy descriptions of metastable supersymmetry breaking models often possess an accidental R-symmetry. Viable phenomenological applications of this class of models require R-symmetry to be broken in the ground state. This can be achieved in O'Raifeartaigh-like models where some of the chiral superfields carry negative R-charges. In this paper we consider UV completions of this class of models and formulate necessary conditions that they must satisfy. We show that the R-symmetry of the IR description can be traced to an anomalous or anomaly-free R-symmetry of the UV theory and discuss seve…
We discuss the thermal evolution of the spurion and messenger fields of ordinary gauge mediation models taking into account the Standard Model degrees of freedom. It is shown that for thermalized messengers the metastable susy breaking vacuum becomes thermally selected provided that the susy breaking sector is sufficiently weakly coupled to messengers or to any other observable field.
We show that supersymmetry and R-symmetry can be dynamically broken in a long-lived metastable vacuum of SQCD with massive and massless flavors. The vacuum results from a competition of a (leading) two-loop effect and small "Planck" suppressed higher-dimension operators. This mechanism provides a particularly simple realization of dynamical SUSY and R-symmetry breaking, and as such it is a good starting point for building phenomenologically viable models of gauge mediation. We take a preliminary step in this direction by constructing a complete model of minimal gauge mediation. Here we find th…
The LHC will probe the nature of the vacuum that determines the properties of particles and the forces between them. Of particular importance is the fact that our current theories allow the Universe to be trapped in a metastable vacuum, which may decay in the distant future, changing the nature of matter. This could be the case in the Standard Model if the LHC finds the Higgs boson to be light. Supersymmetry is one favoured extension of the Standard Model which one might invoke to try to avoid such instability. However, many supersymmetric models are also condemned to vacuum decay for differen…
Thermalisation of configurations with initial white noise power spectrum is studied in numerical simulations of a classical one-component $Φ^4$ theory in 2+1 dimensions, coupled to a small amplitude homogenous external field. The study is performed for energy densities corresponding to the broken symmetry phase of the system in equilibrium. The effective equation of the order parameter motion is reconstructed from its trajectory which starts from an initial value near the metastable point and ends in the stable ground state. This phenomenological theory quantitatively accounts for the decay of…
There is hope that the Large Hadron Collider (LHC) at CERN will tell us about the fate of supersymmetry at the TeVscale. Therefore we might try to identify our expectations for the discovery of SUSY, especially in the first years of operation of this machine. In this talk we shall concentrate on the simplest SUSY scheme: the MSSM with SUSY broken in a hidden sector mediated by interactions of gravitational strength (gravity-, modulus and mirage-mediation). Such a situation might be favoured in a large class of string inspired models. There is a good chance to identify such simple schemes by kn…
We try to find conditions, the fulfillment of which allows a universe born in a metastable false vacuum state to survive and not to collapse. The conditions found are in the form of inequalities linking the depending on time $t$ instantaneous decay rate ${\itΓ}(t)$ of the false vacuum state and the Hubble parameter $H(t)$. Properties of the decay rate of a quantum metastable states are discussed and then the possible solutions of the conditions found are analyzed and discussed. Within the model considered it is shown that a universe born in the metastable vacuum state has a very high chance of…
We study the role of D-terms in supersymmetry (SUSY) breaking. By carefully analyzing the SUSY multiplets containing various conserved currents in theories with global symmetries, we obtain a number of constraints on the renormalization group flow in supersymmetric field theories. Under broad assumptions, these results imply that there are no SUSY-breaking vacua, not even metastable ones, with parametrically large D-terms. This explains the absence of such D-terms in models of dynamical SUSY-breaking. There is, however, a rich class of calculable models which generate comparable D-terms and F-…
We explore the dark matter freeze-in mechanism within the gauge mediation framework, which involves a hidden Feebly Interacting Massive Particle (FIMP) coupling feebly with the messenger fields while the messengers are still in the thermal bath. The FIMP is the fermionic component of the pseudo-moduli in a generic metastable supersymmetry (SUSY) breaking model and resides in the hidden sector. The relic abundance and the mass of the FIMP are determined by the SUSY breaking scale and the feeble coupling. The gravitino, which is the canonical dark matter candidate in the gauge mediation framewor…
Low-scale gauge-mediated supersymmetry(SUSY)-breaking (GMSB) models with gravitino mass m_{3/2}<16 eV are attractive, since there are no flavor and cosmological problems. In this paper, we thoroughly study the collider signal in the case that the next-to-lightest SUSY particle is the bino or slepton and investigate the discovery potential of the LHC. Our result is applicable to a wider class of GMSB models other than the minimal GMSB models and we pay particular attention to realistic experimental setups. We also apply our analysis to the minimal GMSB models with a metastable SUSY-breaking vac…
We present a stringy realization of the ISS metastable SUSY breaking model with moduli stabilization. The mass moduli of the ISS model is stabilized by gauging of a U(1) symmetry and its D-term potential. The SUSY is broken both by F-terms and D-terms. It is possible to obtain de-Sitter vacua with a vanishingly small cosmological constant by an appropriate fine-tuning of flux parameters.
We study supersymmetry breaking in metastable vacua on the Coulomb branch of perturbed N=2 gauge theories, with gauge group SU(2) and different matter content (N_f=0,2,4). The theory is deformed with a superpotential which is a cubic polynomial in u=Tr Φ^2, where Φis the adjoint superfield. The allowed region of the perturbation parameters in this N=1 theory is plotted as a function of the moduli space coordinate. In the asymptotically free cases a significant fine-tuning in the perturbation parameters is needed to achieve metastable vacua in the weakly coupled region of the moduli space; a lo…
We construct a calculable model of low-energy direct gauge mediation making use of the metastable supersymmetry breaking vacua recently discovered by Intriligator, Seiberg and Shih. The standard model gauge group is a subgroup of the global symmetries of the SUSY breaking sector and messengers play an essential role in dynamical SUSY breaking: they are composites of a confining gauge theory, and the holomorphic scalar messenger mass appears as a consequence of the confining dynamics. The SUSY breaking scale is around 100 TeV nevertheless the model is calculable. The minimal non-renormalizable …
A light stop around the weak scale is a hopeful messenger of natural supersymmetry (SUSY), but it has not shown up at the current stage of LHC. Such a situation raises the question of the fate of natural SUSY. Actually, a relatively light stop can easily be hidden in a compressed spectra such as mild mass degeneracy between stop and neutralino plus top quark. Searching for such a stop at the LHC is a challenge. On the other hand, in terms of the argument of natural SUSY, other members in the stop sector, including a heavier stop $\tilde{t}_2$ and lighter sbottom $\tilde{b}_1$ (both assumed to …
We study N=1 global and local supersymmetric theories with a continuous global U(1)_R symmetry. We discuss conditions for supersymmetry (SUSY) breaking and vacuum structures of R-symmetric SUSY models. Especially we find the conditions for R-symmetry breaking and runway vacua in global supersymmetric theories. We introduce explicit R-symmetry breaking terms into such models in global and local supersymmetric theories. We classify explicit R-symmetry breaking terms by the structure of newly appeared SUSY stationary points as a consequence of the R-breaking effect. Based on the generic argument,…
The gauge-mediated SUSY-breaking (GMSB) model needs entropy production at a relatively low temperature in the thermal history of the Universe for the unwanted relics to be diluted. This requires a mechanism for the baryogenesis after the entropy production, and the Affleck and Dine (AD) mechanism is a promising candidate for it. The AD baryogenesis in the GMSB model predicts the existence of the baryonic Q ball, that is the B ball, and this may work as the dark matter in the Universe. In this article, we discuss the stability of the B ball in th presence of baryon-number violating interactions…
