Dynamical Supersymmetry Breaking Research Articles

Supersymmetric particle and Higgs boson masses from the landscape: Dynamical versus spontaneous supersymmetry breaking

Perturbative supersymmetry breaking on the landscape of string vacua is expected to favor large soft terms as a power-law or log distribution, but tempered by an anthropic veto of inappropriate vacua or vacua leading to too large a value for the derived weak scale -- a violation of the atomic principle. Indeed, scans of such vacua yield a statistical prediction for light Higgs boson mass m_h~ 125 GeV with sparticles (save possibly light higgsinos) typically beyond LHC reach. In contrast, models of dynamical SUSY breaking (DSB) -- with a hidden sector gauge coupling g^2 scanned uniformly -- lead to gaugino condensation and a uniform distribution of soft parameters on a log scale. Then soft terms are expected to be distributed as $m_{\rm soft}^{-1}$ favoring small values. A scan of DSB soft terms generally leads to $m_h\ll 125$ GeV and sparticle masses usually below LHC limits. Thus, the DSB landscape scenario seems excluded from LHC search results. An alternative is that the exponential suppression of the weak scale is set anthropically on the landscape via the atomic principle.

Complex Langevin dynamics and supersymmetric quantum mechanics

Using complex Langevin method we probe the possibility of dynamical supersymmetry breaking in supersymmetric quantum mechanics models with complex actions. The models we consider are invariant under the combined operation of parity and time reversal, in addition to supersymmetry. When actions are complex traditional Monte Carlo methods based on importance sampling fail. Models with dynamically broken supersymmetry can exhibit sign problem due to the vanishing of the partition function. Complex Langevin method can successfully evade the sign problem. Our simulations suggest that complex Langevin method can reliably predict the absence or presence of dynamical supersymmetry breaking in these one-dimensional models with complex actions.

Dimers, orientifolds and stability of supersymmetry breaking vacua

We study (orientifolded) toric Calabi-Yau singularities in search for D-brane configurations which lead to dynamical supersymmetry breaking at low energy. By exploiting dimer techniques we are able to determine that while most realizations lead to a Coulomb branch instability, a rather specific construction admits a fully stable supersymmetry breaking vacuum. We describe the geometric structure that a singularity should have in order to host such a construction, and present its simplest example, the Octagon.

Moduli stabilisation and the statistics of SUSY breaking in the landscape

The statistics of the supersymmetry breaking scale in the string landscape has been extensively studied in the past finding either a power-law behaviour induced by uniform distributions of F-terms or a logarithmic distribution motivated by dynamical supersymmetry breaking. These studies focused mainly on type IIB flux compactifications but did not systematically incorporate the Kähler moduli. In this paper we point out that the inclusion of the Kähler moduli is crucial to understand the distribution of the supersymmetry breaking scale in the landscape since in general one obtains unstable vacua when the F-terms of the dilaton and the complex structure moduli are larger than the F- terms of the Kähler moduli. After taking Kähler moduli stabilisation into account, we find that the distribution of the gravitino mass and the soft terms is power-law only in KKLT and perturbatively stabilised vacua which therefore favour high scale supersymmetry. On the other hand, LVS vacua feature a logarithmic distribution of soft terms and thus a preference for lower scales of supersymmetry breaking. Whether the landscape of type IIB flux vacua predicts a logarithmic or power-law distribution of the supersymmetry breaking scale thus depends on the relative preponderance of LVS and KKLT vacua.

On supersymmetry breaking vacua from D-branes at orientifold singularities

We present a large class of models of D-branes at (orientifold) Calabi-Yau sin- gularities which enjoy dynamical supersymmetry breaking at low energy, by means of either the SU(5) or 3–2 supersymmetry breaking models. Once embedded in a warped throat or, equivalently, in a large N theory, all models display an instability along a Coulomb branch direction towards supersymmetry preserving vacua. Interestingly, the nature of the run- away mechanism is model-independent and has a precise geometrical interpretation. This naturally suggests the properties a Calabi-Yau singularity should have in order for such instability not to occur.

Gauge mediation without gravitino problem by virtue of the QCD anomaly

We consider the possibility that the Peccei-Quinn charged dynamical supersymmetry breaking (DSB) mechanism readily accommodates gauge mediation without the gravitino problem. Given a gravitino of ${m}_{3/2}=\mathcal{O}(\mathrm{eV})$ for the Intriligator-Seiberg-Shih model, an axion, converted from a Nambu-Goldstone boson, could become a dark matter candidate, while the QCD anomaly and a sizable $\ensuremath{\mu}$ value are naturally generated. We also stress that rather minimal DSB content is sufficient to yield the observed mass of the lightest Higgs boson, other than the acceptable soft mass of sparticles in the observable sector.

Dynamical supersymmetry breaking in large Nc supersymmetric QCD

We study dynamical supersymmetry breaking in supersymmetric QCD theories for $N_f<N_c$. We consider a model with a singlet chiral superfield coupled to the infrared meson chiral superfield through a classical superpotential. We examine the vacuum structure of this model and show that in a particular limit of the parameter space with the large $N_c$ limit, it has a vacuum that dynamically breaks supersymmetry. The supersymmetric vacuum, in this limit, is being pushed to infinity.

Constraining R-axion models through dijet searches at the LHC

The search at hadron colliders for new massive resonances of a few 100 GeVs that couple effectively to colored states is an extremely challenging issue, due principally to the presence of large QCD multijet backgrounds at this energy, rendering the searches at the LHC particularly difficult. Recently, it was realized that these large backgrounds could be overcome by demanding one high-pT jet from initial-state radiation (ISR) and by means of novel jet-reconstruction techniques through which the resulting hadronized products of the massive resonances are reconstructed as a fat-jet, a unique large-radius jet. The ATLAS and CMS Collaborations have recently reported searches for the experimental signature of a single fat-jet in association with an ISR jet. Models of dynamical supersymmetry breaking with an spontaneously broken R-symmetry give rise to the appearance of a pseudo-Nambu–Goldstone boson called the R-axion, which naturally tends to be light. In the parameter space regions where the anomalous R-axion coupling to gluons is boosted, these models can be tested against these new LHC dijet searches. Taking into account the CMS search, we apply the qμ statistical method to the signal events against the background-only expectation and obtain the 95% C.L. exclusion limits on the most relevant model parameters for a particular messenger sector, namely, the R-axion mass ma, the decay constant fa, and the number of color messengers N, being these limits suitable to be applied to more general models with axion-like particles.

Do we live in the swampland?

A low-energy effective theory is said to be in the swampland if it does not have any consistent UV completion inside a theory of quantum gravity. The natural question is if the standard model of particle physics, possibly with some minimal extensions, are in the swampland — we are in trouble if the answer to this question is yes. We discuss this question in view of the recent swampland conjectures. We prove a no-go theorem concerning the modification of the Higgs sector. Moreover, we find that QCD axion is incompatible with the recent swampland conjectures, unless some sophisticated possibilities are considered. We discuss the implications of this result for spontaneous breaking of CP symmetry. We comment on dynamical supersymmetry breaking as well as the issue of multi-valuedness of the potential. We also propose a refinement of the de Sitter swampland conjecture.

Nonperturbative study of dynamical SUSY breaking in N=(2,2) Yang-Mills theory

We examine the possibility of dynamical supersymmetry breaking in two-dimensional $\mathcal{N} = (2, 2)$ supersymmetric Yang-Mills theory. The theory is discretized on a Euclidean spacetime lattice using a supersymmetric lattice action. We compute the vacuum energy of the theory at finite temperature and take the zero temperature limit. Supersymmetry will be spontaneously broken in this theory if the measured ground state energy is non-zero. By performing simulations on a range of lattices up to $96 \times 96$ we are able to perform a careful extrapolation to the continuum limit for a wide range of temperatures. Subsequent extrapolations to the zero temperature limit yield an upper bound on the ground state energy density. We find the energy density to be statistically consistent with zero in agreement with the absence of dynamical supersymmetry breaking in this theory.

Possible Approach to Dynamical Supersymmetry Breaking via Nambu-Jona-Lasinio Model

Supersymmetry is undoubtedly a popular candidate for physics beyond the Standard Model. However, the origin of soft supersymmetry breaking masses has been usually depicted intricately in the literature via extra hidden/mediating sectors. Thus, a simple theory for the generation of the soft masses would be more compelling. Here we discuss a possible approach to dynamical supersymmetry breaking via Nambu-Jona- Lasinio (NJL) Model, which has been missed since the first investigation of supersymmetric NJL model. We introduce a four-superfield interaction term that induces a real two-superfield composite with vacuum condensate. The latter has supersymmetry breaking parts, which we show to bear nontrivial solutions following a standard nonperturbative analysis for a NJL type model. The presence of the expected Goldstino state along with the supersymmetry breaking, is also verified. Moreover, the model gives rise to a composite spin one field, as its important characteristic.

Higgs mass in D-term triggered dynamical SUSY breaking

We discuss a new mechanism of D-term dynamical supersymmetry breaking in the context of Dirac gaugino scenario. The existence of a nontrivial solution of the gap equation for D-term is shown. It is also shown that an observed 126 GeV Higgs mass is realized by tree level D-term effects in a broad range of parameters.

Unified model of chaotic inflation and dynamical supersymmetry breaking

The large hierarchy between the Planck scale and the weak scale can be explained by the dynamical breaking of supersymmetry in strongly coupled gauge theories. Similarly, the hierarchy between the Planck scale and the energy scale of inflation may also originate from strong dynamics, which dynamically generate the inflaton potential. We present a model of the hidden sector which unifies these two ideas, i.e., in which the scales of inflation and supersymmetry breaking are provided by the dynamics of the same gauge group. The resultant inflation model is chaotic inflation with a fractional power-law potential in accord with the upper bound on the tensor-to-scalar ratio. The supersymmetry breaking scale can be much smaller than the inflation scale, so that the solution to the large hierarchy problem of the weak scale remains intact. As an intrinsic feature of our model, we find that the sgoldstino, which might disturb the inflationary dynamics, is automatically stabilized during inflation by dynamically generated corrections in the strongly coupled sector. This renders our model a field-theoretical realization of what is sometimes referred to as sgoldstino-less inflation.

Unified model of D-term inflation

Hybrid inflation, driven by a Fayet-Iliopoulos (FI) D term, is an intriguing inflationary model. In its usual formulation, it however suffers from several shortcomings. These pertain to the origin of the FI mass scale, the stability of scalar fields during inflation, gravitational corrections in supergravity, as well as to the latest constraints from the cosmic microwave background. We demonstrate that these issues can be remedied if D-term inflation is realized in the context of strongly coupled supersymmetric gauge theories. We suppose that the D term is generated in consequence of dynamical supersymmetry breaking. Moreover, we assume canonical kinetic terms in the Jordan frame as well as an approximate shift symmetry along the inflaton direction. This provides us with a unified picture of D-term inflation and high-scale supersymmetry breaking. The D term may be associated with a gauged U(1)_B-L, so that the end of inflation spontaneously breaks B-L in the visible sector.

Implications of heavy neutralino dark matter: The underlying structure in the hidden sector

The possibility of heavy neutralino dark matter (DM) in the gravity-mediation mechanism is explored. The appearance of the heavy lightest supersymmetric particle is seemingly suggested by Large Hadron Collider runs, which have not provided evidence of superparticles around the TeV region. On the basis of the so-called WIMPZILLA scenario, it is understood that the nonthermally produced DM has the larger mass than the reheating temperature. Hence, the expected DM mass should be more than 109 GeV so that thermal leptogenesis successfully occurs. In this paper, we first examine the generation of the Higgsino mass parameter [Formula: see text] in the context of gravity mediation, postulating that the resolution of the strong CP problem should be the criterion for arriving at a valid hypothesis for heavy neutralino DM. Accordingly, we address how the Peccei–Quinn (PQ) symmetry could influence dynamical supersymmetry breaking (DSB) models. It is found that as long as [Formula: see text] (the SUSY-breaking scale) approximately coincides with [Formula: see text] (the PQ-breaking scale), no DSB models can naturally account for the existence of the heavy neutralino DM, based upon the supersymmetric Dine–Fischler–Srednicki–Zhitinitski (DFSZ)-like mechanism. Thus, we attempt to construct a new model wherein hierarchical SUSY breakings occur. For this purpose, we propose gauge coupling unification in the hidden-sector dynamics at some high-energy scale, and we show that such a class of models can achieve [Formula: see text] through renormalization flow. As a consequence, the nonthermal neutralino, practically the wino-like one in our model, is shown to be a rather natural and viable DM candidate. Moreover, we argue that on the basis of Kac–Moody algebra, multiple breakdowns of supersymmetry may entail unified gauge dynamics. We also present a possible unified model. Finally, the heavy wino-like neutralino may be a DM candidate that will favor future direct DM detection experiments, mainly because its scattering on nuclei well conserves isospin symmetry.

Classical and quantum stability in putative landscapes

Landscape analyses often assume the existence of large numbers of fields, N , with all of the many couplings among these fields (subject to constraints such as local supersymmetry) selected independently and randomly from simple (say Gaussian) distributions. We point out that unitarity and perturbativity place significant constraints on behavior of couplings with N , eliminating otherwise puzzling results. In would-be flux compactifications of string theory, we point out that in order that there be large numbers of light fields, the compactification radii must scale as a positive power of N ; scaling of couplings with N may also be necessary for perturbativity. We show that in some simple string theory settings with large numbers of fields, for fixed R and string coupling, one can bound certain sums of squares of couplings by order one numbers. This may argue for strong correlations, possibly calling into question the assumption of uncorrelated distributions. We consider implications of these considerations for classical and quantum stability of states without supersymmetry, with low energy supersymmetry arising from tuning of parameters, and with dynamical breaking of supersymmetry.

Dynamical supersymmetry breaking and late-timeRsymmetry breaking as the origin of cosmic inflation

Spontaneously broken supersymmetry (SUSY) and a vanishingly small cosmological constant imply that R symmetry must be spontaneously broken at low energies. Based on this observation, we suppose that, in the sector responsible for low-energy R symmetry breaking, a discrete R symmetry remains preserved at high energies and only becomes dynamically broken at relatively late times in the cosmological evolution, i.e., after the dynamical breaking of SUSY. Prior to R symmetry breaking, the Universe is then bound to be in a quasi-de Sitter phase---which offers a dynamical explanation for the occurrence of cosmic inflation. This scenario yields a new perspective on the interplay between SUSY breaking and inflation, which neatly fits into the paradigm of high-scale SUSY: inflation is driven by the SUSY-breaking vacuum energy density, while the chiral field responsible for SUSY breaking, the Polonyi field, serves as the inflaton. Because R symmetry is broken only after inflation, slow-roll inflation is not spoiled by otherwise dangerous gravitational corrections in supergravity. We illustrate our idea by means of a concrete example, in which both SUSY and R symmetry are broken by strong gauge dynamics and in which late-time R symmetry breaking is triggered by a small inflaton field value. In this model, the scales of inflation and SUSY breaking are unified; the inflationary predictions are similar to those of F-term hybrid inflation in supergravity; reheating proceeds via gravitino decay at temperatures consistent with thermal leptogenesis; and the sparticle mass spectrum follows from pure gravity mediation. Dark matter consists of thermally produced winos with a mass in the TeV range.

Dynamical supersymmetry breaking on magnetized tori and orbifolds

We construct several dynamical supersymmetry breaking (DSB) models within a single ten-dimensional supersymmetric Yang–Mills (SYM) theory, compactified on magnetized tori with or without orbifolding. We study the case that the supersymmetry breaking is triggered by a strong dynamics of SU(NC) SYM theory with NF flavors contained in the four-dimensional effective theory. We show several configurations of magnetic fluxes and orbifolds, those potentially yield, below the compactification scale, the field contents and couplings required for triggering DSB. We especially find a class of self-complete DSB models on orbifolds, where all the extra fields are eliminated by the orbifold projection and DSB successfully occurs within the given framework. Comments on some perspectives for associating the obtained DSB models with the other sectors, such as the visible sector and another hidden sector for, e.g., stabilizing moduli, are also given.

Orientifolds of warped throats from toric Calabi-Yau singularities

We study the complex deformations of orientifolds of D3-branes at toric CY singularities, using their description in terms of dimer diagrams. We describe orientifold quotients that have fixed lines or fixed points in the dimer, and characterize the possibilities to deform them in terms of the behaviour of zig-zag paths under the orientifold symmetry. The resulting models are holographic duals to warped throats with orientifold planes. Our systematic construction provides a general class of configurations which includes models recently appeared in the context of de Sitter uplift by nilpotent goldstino or dynamical supersymmetry breaking.

Nambu–Jona-Lasinio theory and dynamical breaking of supersymmetry

A recently proposed new mechanism of D-term triggered dynamical supersymmetry breaking is reviewed. Supersymmetry is dynamically broken by nonvanishing D-term vacuum expectation value, which is realized as a nontrivial solution of the gap equation in the self-consistent approximation as in the case of Nambu-Jona-Lasinio model and BCS superconductivity.