We present a simple supersymmetric axion model that can naturally explain the origin of the Higgs mu and Bmu terms in gauge mediation while solving the strong CP problem. To stabilize the Peccei-Quinn scale, we consider mixing between the messenger fields that communicate the supersymmetry and Peccei-Quinn symmetry breaking to the visible sector. Such mixing leads to the radiative stabilization of the Peccei-Quinn scale. In the model, a Higgs coupling to the axion superfield generates the B parameter at the soft mass scale while a small mu term is induced after the Peccei-Quinn symmetry breaking. We also explore the phenomenological and cosmological aspects of the model, which crucially depend on the saxion and axino interactions with the ordinary particles induced by the Higgs coupling to the axion superfield.
We present a new approach to the mu-Bmu problem of gauge mediated supersymmetry breaking. Rather than reducing the generically large contribution to Bmu we point out that acceptable electroweak symmetry breaking can be achieved with mu^2 << Bmu if at the same time Bmu << m_Hd^2. This hierarchy can easily appear in models where the Higgs fields are directly coupled to the supersymmetry breaking sector. Such models can yield novel electroweak symmetry breaking vacua, can deal with the supersymmetric flavor and CP problems, allow for gauge coupling unification, and result in distinct phenomenolog…
We show that in gauge mediation models where heavy messenger masses are provided by the adjoint Higgs field of an underlying SU(5) theory, a generalized gauge mediation spectrum arises with the characteristic feature of having a neutralino LSP much lighter than in the standard gauge or gravity mediation schemes. This naturally fits in a hybrid scenario where gravity mediation, while subdominant with respect to gauge mediation, provides mu and Bmu parameters of the appropriate size for electroweak symmetry breaking.
Similarities between the gauge meditation of supersymmetry breaking and the QCD axion model suggest that they originate from the same dynamics. We present a class of models where supersymmetry and the Peccei-Quinn symmetry are simultaneously broken. The messengers that mediate the effects of these symmetry breakings to the Standard Model are identical. Since the axion resides in the supersymmetry breaking sector, the saxion and the axino are heavy. We show constraints on the axion decay constant and the gravitino mass.
The recently proposed model of using the dynamical phase of the gluino to solve the strong CP problem is shown to admit a specific realization in terms of fundamental singlet superfields, such that the breaking of supersymmetry occurs only at the TeV scale, despite the large axion scale of 10^{9} to 10^{12} GeV. Phenomenological implications are discussed.
In the axionic solution of the strong CP problem, fermions which transform under quantum chromodynamics (QCD) are required. In supersymmetry, by equating U(1)_{PQ} with U(1)_R, the natural candidates are the gluinos, as pointed out some years ago. A new specific implementation of this idea is proposed, linking the gluino axion scale to that of the canonical seesaw mechanism for neutrinos. Gaugino masses are generated dynamically and the A term is predicted to be very small.
We propose a possibility of the 125 GeV Higgs being a pseudo-Goldstone boson in supersymmetry with extra vector-like fermions. Higgs mass is obtained from loops of top quark and vector-like fermions from the global symmetry breaking scale f at around TeV. The mu, Bmu/mu \sim f are generated from the dynamics of global symmetry breaking and the Higgs quartic coupling vanishes at f as tan beta \simeq 1. The relation of msoft \sim $4πM_Z$ with f \sim mu \sim m_soft \sim TeV is obtained and large mu does not cause a fine tuning for the electroweak symmetry breaking. The Higgs to di-photon rate can…
The minimal supersymmetric standard model (MSSM) of particle interactions is extended to include three singlet (right-handed) neutrino superfields together with three other singlet superfields. The resulting theory is assumed to be invariant under an anomalous global U(1) (Peccei-Quinn) symmetry with one fundamental mass $m_2$. The soft breaking of supersymmetry at the TeV scale is shown to generate an axion scale $f_a$ of order $m_2$. Neutrino masses are generated by $f_a$ according to the usual seesaw mechanism.
Recently we have proposed a simple hadronic axion model within gauge-mediated supersymmetry breaking. In this paper we discuss various cosmological consequences of the model in great detail. A particular attention is paid to a saxion, a scalar partner of an axion, which is produced as a coherent oscillation in the early universe. We show that our model is cosmologically viable, if the reheating temperature of inflation is sufficiently low. We also discuss the late decay of the saxion which gives a preferable power spectrum of the density fluctuation in the standard cold dark matter model when …
The axion solution to the strong CP problem makes use of a global Peccei-Quinn (PQ) U(1) symmetry which is susceptible to violations from quantum gravitational effects. We show explicitly how discrete gauge symmetries can protect the axion from such violations. PQ symmetry emerges as an accidental global symmetry from discrete gauge symmetries which are subgroups of the anomalous U(1) of string origin. We also show how the Dine-Fischler-Srednicki-Zhitnitsky (DFSZ) axion model provides a natural solution to mu problem of supersymmetry as mu ~ M_{SUSY} ~ M^2_{PQ}/M_{Pl}.
We construct hadronic axion models in the framework of the anomaly-mediated supersymmetry breaking scenario. If the Peccei-Quinn symmetry breaking is related to the supersymmetry breaking, mass spectrum of the minimal anomaly-mediated scenario is modified, which may solve the negative slepton mass problem in the minimal anomaly-mediated model. We find several classes of phenomenologically viable models of axion within the framework of the anomaly mediation and, in particular, we point out a new mechanism of stabilizing the axion potential. In this class of models, the Peccei-Quinn scale is rel…
We extend the work of Carone, Chaurasia and Vasquez on non-supersymmetric models of flavor based on the double tetrahedral group. Three issues are addressed: (1) the sector of flavor-symmetry-breaking fields is simplified and their potential studied explicitly, (2) a flavorful axion is introduced to solve the strong CP problem and (3) the model is extended to include the neutrino sector. We show how the model can accommodate the strong hierarchies manifest in the charged fermion Yukawa matrices, while predicting a qualitatively different form for the light neutrino mass matrix that is consiste…
After promoting the phases of the soft masses to dynamical fields corresponding to Goldstone bosons of spontaneously broken global symmetries in the supersymmetry breaking sector, the next-to-minimal supersymmetric model is found to solve the $μ$ problem and the strong CP problem simultaneously with an invisible axion. The domain wall problem persists in the form of axionic domain formation. Relaxation dynamics of the physical CP-violating phases is determined only by the short-distance physics and their relaxation values are not necessarily close to the CP-conserving points. Having observable…
A simple hadronic axion model is proposed in the framework of gauge-mediated supersymmetry breaking. Dynamics of Peccei-Quinn symmetry breaking is governed by supersymmetry breaking effects and the Peccei-Quinn breaking scale $f_{PQ}$ is inversely proportional to the gravitino mass. The gravitino mass range which corresponds to the axion window $f_{PQ} \simeq 10^{9}$ GeV -- $10^{13}$ GeV lies in the region predicted by gauge-mediated supersymmetry breaking models. The model is also shown to be cosmologically viable.
By eschewing finetuning from the electroweak and QCD sectors of supersymmetry (natural supersymmetry or SUSY), and by invoking the Kim-Nilles solution to the SUSY mu problem, one is lead to models wherein the dark matter is comprised of a mixture of axions and higgsino-like WIMPs. Over a large range of Peccei-Quinn breaking scale f_a~ 10^9-10^{12} GeV, one then expects about 90-95% axion dark matter. In such a scenario, both axion and WIMP direct detection may be expected.
Inspired by the possibility of high-scale supersymmetry breaking in the string landscape where the cosmological constant problem and the gauge hierarchy problem can be solved while the strong CP problem is still a challenge for naturalness, we propose a supersymmetric KSVZ axion model with an approximate universal intermediate-scale ($\sim 10^{11}$ GeV) supersymmetry breaking. To protect the global Peccei--Quinn (PQ) symmetry against quantum gravitational violation, we consider the gauged discrete $Z_N$ PQ symmetry. In our model the axion can be a cold dark matter candidate, and the intermedia…
Various authors have noted that in particular models, the upper bound on the axion decay constant may not hold. We point out that within supersymmetry, this is a generic issue. For large decay constants, the cosmological problems associated with the axion's scalar partner are far more severe than those of the axion. We survey a variety of models, both for the axion multiplet and for cosmology, and find that in many cases where the cosmological problems of the saxion are solved, the usual upper bound on the axion is significantly relaxed. We discuss, more generally, the cosmological issues rais…
The axion solution to the strong CP problem requires an anomalous global U(1) symmetry. We show that the existence of such a symmetry is a natural consequence of an extra dimension in which a gauged U(1) is spontaneously broken on one of two branes, leaving an accidental global symmetry on the other brane. Depending on where the standard model matter lives, the resulting axion can be either the DFSZ or hadronic type. Gaugino-mediated supersymmetry breaking fits comfortably in our framework. In addition, we present a model in which the supersymmetry-breaking and Peccei-Quinn breaking scales are…
We investigate O'Raifeartaigh-type models for F-term supersymmetry breaking in gauge mediation scenarios in the presence of gravity. It is pointed out that the vacuum structure of those models is such that in metastable vacua gravity mediation contribution to scalar masses is always suppressed to the level below 1 percent, almost sufficient for avoiding FCNC problem. Close to that limit, gravitino mass can be in the range 10-100 GeV, opening several interesting possibilities for gauge mediation models, including Giudice-Masiero mechanism for mu and Bmu generation. Gravity sector can include st…
We show that the hierarchically small mu term in supersymmetric theories is a consequence of two identical pairs of Higgs doublets taking a democratic form for their mass matrix. We briefly discuss the discrete symmetry S2xS2 toward the democratic mass matrix. Then, we show that there results an approximate Peccei-Quinn symmetry and hence the value mu is related to the axion decay constant.
The $μ$ term in the supersymmetric standard model is known to" be nonzero. Supersymmetry breaking at the intermediate scale may provide the needed $μ$ term and the invisible axion. A possible solution of this $μ$ problem in superstring models is also discussed.
Various theoretical and experimental considerations motivate models with high scale supersymmetry breaking. While such models may be difficult to test in colliders, we propose looking for signatures at much lower energies. We show that a keV line in the X-ray spectrum of galaxy clusters (such as the recently disputed 3.5 keV observation) can have its origin in a universal string axion coupled to a hidden supersymmetry breaking sector. A linear combination of the string axion and an additional axion in the hidden sector remains light, obtaining a mass of order 10 keV through supersymmetry break…
We consider a supersymmetric realization of the MSSM Higgs sector, where the soft terms are promoted to supersymmetric operators and a minimal weakly coupled hidden sector is included. The model exhibits long-lived meta-stable vacua in which supersymmetry and electroweak symmetry are spontaneously broken. The spectrum contains, in addition to the usual MSSM particles and the goldstino fermion, a CP-even and a CP-odd scalar in the neutral Higgs sector corresponding to the complex sgoldstino scalar. By treating all the components of the goldstino supermultiplet dynamically and taking into accoun…
In a supersymmetric axion model where the scale for both supersymmetry breaking and Peccei-Quinn symmetry breaking is around $10^{11}$ GeV, we find that there is a reasonable parameter space for a strongly first order phase transition at the scale.
String theoretic axion is a prime candidate for the QCD axion solving the strong CP problem. For a successful realization of the QCD axion in string theory, one needs to stabilize moduli including the scalar partner (saxion) of the QCD axion, while keeping the QCD axion unfixed until the low energy QCD instanton effects are turned on. We note that a simple generalization of KKLT moduli stabilization provides such set-up realizing the axion solution to the strong CP problem. Although some details of moduli stabilization are different from the original KKLT scenario, this set-up leads to the mir…
We study the interplay between the spontaneous breaking of a global symmetry of the Higgs sector and gauge-mediated supersymmetry breaking, in the framework of a supersymmetric model with global SU(3) symmetry. In addition to solving the supersymmetric flavour problem and alleviating the little hierarchy problem, this scenario automatically triggers the breaking of the global symmetry and provides an elegant solution to the mu/Bmu problem of gauge mediation. We study in detail the processes of global symmetry and electroweak symmetry breaking, including the contributions of the top/stop and ga…
We propose a new framework of low-scale gauge-mediated supersymmetry (SUSY) breaking with a gravitino mass of O(100) TeV. The usual 4D gauge mediation models predict a light gravitino and suffer from cosmological problems. In our framework, a heavy gravitino in gauge mediation is realized with a flat extra-dimension, whose compactification scale is around the grand unified theory scale. Superparticle masses of the visible sector from gravity/anomaly mediation are suppressed, and they are purely generated by usual gauge mediation on the visible brane. Importantly, the Higgs Bmu-term vanishes at…
Evidence is mounting that natural supersymmetry at the weak scale is not realized in nature. On the other hand, string theory suggests that supersymmetry may be present at some energy scale, and gauge coupling unification implies that that energy scale may be relatively low. A puzzling question is then why nature would prefer a low, but not completely natural supersymmetry breaking scale. Here we offer one possible explanation, which simultaneously addresses also the strong CP and mu problems. We introduce an axion, and suppose that the Peccei-Quinn and supersymmetry breaking scales are connec…
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 $m_{3/2}$ but also for enhancing it during inflation by factor of order $\sqrt{H_I/m_{3/2}}$ where $H_I \simeq 10^{14}$ 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 $10^{10}$ GeV, or $m_{3/2}$ when the P…
We propose a hybrid mediation and hybrid supersymmetry breaking. In particular the RG-invariant anomaly mediation is considered. Together with additional gravity mediation the slepton tachyon problem of anomaly mediation is solved automatically. The special properties are that all of color sparticles masses fall into several TeV region due to the large $m_0$ and $m_{32}$ which are well beyond the scope of current LHC Run II limits. Unlike the gauge mediation, the dark matter candidate is still the lightest neutralino and the correct dark matter relic density can be realized within the framewor…
We illustrate the structure and the main phenomenological features of a supersymmetric model (the USSM-A) built following a bottom-up approach and containing an anomalous abelian gauge symmetry. This model supports a gauged axion in its spectrum and provides a generalization of the global (supersymmetric) Peccei-Quinn construction. Complete simulations of the neutralino relic density are performed. Bounds from CAST and WMAP, combined with dark matter simulations, provide significant constraints on the scale of the interactions between the axion and the gauge fields.
While axions seem ubiquitous in critical string theories, whether they might survive in any string theoretic description of nature is a difficult question. With some mild assumptions, one can frame the issues in the case that there is an approximate supersymmetry below the underlying string scale. The problem of axions is then closely tied to the question of how moduli are fixed. We consider, from this viewpoint, the possibility that supersymmetry is broken at an intermediate scale, as in "gravity mediation," at a low scale, as in gauge mediation, and at a very high scale, to model the possibi…
We study properties of moduli stabilization in the four dimensional N = 1 supergravity theory with heavy moduli and would-be saxion-axion multiplets including light string-theoretic axions. We give general formulation for the scenario that heavy moduli and saxions are stabilized while axions remain light, assuming that moduli are stabilized near the supersymmetric solution. One can find stable vacuum, i.e. non-tachyonic saxions, in the non-supersymmetric Minkowski vacua. We also discuss the cases, where the moduli are coupled to the supersymmetry breaking sector and/or moduli have contribution…
We discuss a scheme to implement the relaxion solution to the hierarchy problem with multiple axions, and present a UV-completed model realizing the scheme. All of the $N$ axions in our model are periodic with a similar decay constant $f$ well below the Planck scale. In the limit $N\gg 1$, the relaxion $ϕ$ corresponds to an exponentially long multi-helical flat direction which is shaped by a series of mass mixing between nearby axions in the compact field space of $N$ axions. With the length of flat direction given by $Δϕ=2πf_{\rm eff} \sim e^{ξN} f$ for $ξ={\cal O}(1)$, both the scalar potent…
A class of supersymmetric grand unified theories is introduced that has a single scale below the cutoff, that of the supersymmetry breaking masses $\tilde{m}$. For a wide range of the dimensionless parameters, agreement with the observed mass of the Higgs boson determines $\tilde{m} \sim 10^9-10^{13} {\rm GeV}$, yielding Intermediate Scale Supersymmetry. We show that within this framework it is possible for seesaw neutrino masses, axions, and inflation to be described by the scale $\tilde{m}$, offering the possibility of a unified origin of disparate phenomena. Neutrino masses allowing for the…
In a supersymmetric theory with global U(1) invariance, the spontaneous breaking of the latter without the breaking of supersymmetry is revisited in the case of the most general superpotential of 3 singlet superfields. The interesting possibility of having 2 hierarchical mass scales is pointed out, together with its consequences as applied to the axionic solution of the strong CP problem.
In the post-LHC8 era, it is perceived that what is left of SUSY model parameter space is highly finetuned in the EW sector (EWFT). We discuss how conventional measures overestimate EWFT in SUSY theory. Radiatively-driven natural SUSY (RNS) models maintain the SUSY GUT paradigm with low EWFT at 10% level, but are characterized by light higgsinos ~100-300 GeV and a thermal underabundance of WIMP dark matter. Implementing the SUSY DFSZ solution to the strong CP problem explains the small μparameter but indicates dark matter should be comprised mainly of axions with a small admixture of higgsino-l…
We consider a scenario where the supersymmetry breaking and its mediation, and the cancellation of the theta parameter of SU(3)c are all caused by a single chiral multiplet. The string axion multiplet is a natural candidate of such a single superfield. We show that the scenario provides a convincing basis of focus point gaugino mediation, where the electroweak scale is explained with a moderate tuning among the parameters of the theory.
Implications of supersymmetrizing the clockwork axions are studied. Supersymmetry ensures that the saxions and axinos have the same pattern of the coupling hierarchy as the clockwork axions. If we assume supersymmetry breaking is universal over the clockwork sites, the coupling structure is preserved, while the mass orderings of the saxions and axinos can differ depending on the supersymmetry breaking scale. While the massive saxions and axions quickly decay, the lightest axino can be stable and thus a dark matter candidate. The relic abundance of the axino dark matter from thermal production …
In this talk, we propose a model of mirage mediation, in which Peccei-Quinn symmetry is incorporated. In this \textit{axionic mirage mediation}, it is shown that the Peccei-Quinn symmetry breaking scale is dynamically determined around $10^{10}$ GeV to $10^{12}$ GeV due to the supersymmetry breaking effects. The problems in the original mirage mediation such as the $μ$-problem and the moduli problem can be solved simultaneouly. Furthermore, in our model the axino, which is the superpartner of the axion, is the lightest sparticle.
In the effective field theory framework, we consider the effect of supersymmetry breaking via gaugino condensation and supergravity in the hidden sector gauge group on the hidden sector vacuum angle $θ_h$. The $θ_h$ parameter dependence of the potential yields phenomenologically acceptable invisible axion solutions if the $U(1)_R$ symmetry is broken down to a discrete subgroup $Z_N$ with $N\ge 3$ (N=4 is marginal). Anomalous U(1) superstring models are good candidates for this invisible axion resolution of the strong CP puzzle.
Weak scale supersymmetry is a highly motivated extension of the Standard Model that has a strong degree of support from data. It provides several viable dark matter candidates: the lightest neutralino (a WIMP), the gravitino, and the axion/axino supermultiplet. The LHC turn-on is imminent. The discovery of supersymmetry at the LHC will go a long way towards establishing the nature of dark matter. I present arguments why mainly axion cold dark matter is a better fit for supersymmetric models than neutralinos. I also argue that Yukawa-unified SUSY GUT theories based on SO(10) with mixed axion/ax…
We explore the possibility that supersymmetry breaking is mediated to the Standard Model sector through the interactions of a generalized axion multiplet that gains a F-term expectation value. Using an effective field theory framework we enumerate the most general possible set of axion couplings and compute the Standard Model sector soft-supersymmetry-breaking terms. Unusual, non-minimal spectra, such as those of both natural and split supersymmetry are easily implemented. We discuss example models and low-energy spectra, as well as implications of the particularly minimal case of mediation vi…
By insisting on naturalness in both the electroweak and QCD sectors of the MSSM, the portrait for dark matter production is seriously modified from the usual WIMP miracle picture. In SUSY models with radiatively-driven naturalness (radiative natural SUSY or RNS) which include a DFSZ-like solution to the strong CP and SUSY mu problems, dark matter is expected to be an admixture of both axions and higgsino-like WIMPs. The WIMP/axion abundance calculation requires simultaneous solution of a set of coupled Boltzmann equations which describe quasi-stable axinos and saxions. In most of parameter spa…
Models of natural supersymmetry seek to solve the little hierarchy problem by positing a spectrum of light higgsinos \lesssim 200 GeV and light top squarks \lesssim 500 GeV along with very heavy squarks and TeV-scale gluinos. Such models have low electroweak finetuning and are safe from LHC searches. However, in the context of the MSSM, they predict too low a value of m(h) and the relic density of thermally produced higgsino-like WIMPs falls well below dark matter (DM) measurements. Allowing for high scale soft SUSY breaking Higgs mass m_{H_u}> m_0 leads to natural cancellations during RG runn…
Mirage mediation reduces the fine-tuning in the minimal supersymmetric standard model by dynamically arranging a cancellation between anomaly-mediated and modulus-mediated supersymmetry breaking. We explore the conditions under which a mirage "messenger scale" is generated near the weak scale and the little hierarchy problem is solved. We do this by explicitly including the dynamics of the SUSY-breaking sector needed to cancel the cosmological constant. The most plausible scenario for generating a low mirage scale does not readily admit an extra-dimensional interpretation. We also review the p…
We present a supersymmetric version of a two-field relaxion model that naturalizes tuned versions of supersymmetry. This arises from a relaxion mechanism that does not depend on QCD dynamics and where the relaxion potential barrier height is controlled by a second axion-like field. During the cosmological evolution, the relaxion rolls with a nonzero value that breaks supersymmetry and scans the soft supersymmetric mass terms. Electroweak symmetry is broken after the soft masses become of order the supersymmetric Higgs mass term and causes the relaxion to stop rolling for superpartner masses up…
We consider the class of effective supergravity theories from the weakly coupled heterotic string in which local supersymmetry is broken by gaugino condensation in a hidden sector, with dilaton stabilization achieved through corrections to the classical dilaton Kähler potential. If there is a single hidden condensing (simple) gauge group, the axion is massless (up to contributions from higher dimension operators) above the QCD condensation scale. We show how the standard relation between the axion mass and its Planck scale coupling constant is modified in this class of models due to a contribu…
A Supersymmetric Extension of Axionic Electrodynamics: From Axions and Photons to Axinos and Photinos
Universidade Federal do Espírito Santo（圣埃斯皮里图联邦大学）；Centro Brasileiro de Pesquisas Físicas（巴西物理研究中心）；Instituto Federal do Espírito Santo（圣埃斯皮里图联邦学院）；Centro Federal de Educação Tecnológica C. S. da Fonseca（C.S.达丰塞卡联邦技术教育中心）
The effects of supersymmetry breaking are usually parameterized by soft couplings of positive mass dimensions. However, realistic models also predict the existence of suppressed, but non-vanishing, dimensionless supersymmetry-breaking couplings. These couplings are technically hard, but do not lead to disastrous quadratic divergences in scalar masses, and may be crucial for understanding low-energy physics. In particular, analytic scalar quartic couplings that break supersymmetry can lead to intermediate scale vacuum expectation values along nearly-flat directions. I study the one-loop effecti…
