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A conformal gauge mediation and dark matter with only one mass parameter
Abstract
If the supersymmetry (SUSY) is a solution to the hierarchy problem, it is puzzling that any SUSY particle has not been discovered yet. We show that there is a low-scale conformal gauge mediation model which contains all necessary ingredients, i.e. not only a SUSY-breaking dynamics and a gauge mediation mechanism, but also a candidate for the dark matter. The model has only one free mass parameter, that is, the mass for messengers. In this model, the dark matter is provided by a composite particle in the SUSY-breaking sector, and the observed value of the dark matter density uniquely fixes the mass of messengers at the order of 102 TeV. Then, the sfermion and gaugino masses are fixed to be of order 102–103 GeV without any arbitrariness, thus the SUSY particles are expected not to be discovered at the Tevatron or LEP, while having a discovery possibility at the LHC.
... Bearing these merits of GMSB models, in this paper, we give our special attention to a class of GMSB models dubbed "conformal gauge mediation (CGM)" [7,8] (see also the follow-up works in [9,10]). Differing from many of GMSB models, this type of GMSB model has the interesting property of having less number of free parameters. ...
... Therefore, it becomes necessary to consider the strongly coupled gauge mediation scenario [17]. As an exemplary model satisfying this feature, we give our special attention to the strongly interacting conformal gauge mediation model [7][8][9][10]. Therein SUSY-breaking is induced by the presence of a conformal phase of a hidden non-Abelian gauge theory of which the strong dynamics accounts for the interactions in the messenger sector and SUSY-breaking sector. ...
... Therein SUSY-breaking is induced by the presence of a conformal phase of a hidden non-Abelian gauge theory of which the strong dynamics accounts for the interactions in the messenger sector and SUSY-breaking sector. Below, we first go through a review of the existing strongly interacting conformal gauge mediation model [7][8][9][10] and then in the next subsection we extend it by introducing a new field content. ...
A bstract
By extending a previously proposed conformal gauge mediation model, we construct a gauge-mediated SUSY breaking (GMSB) model where a SUSY-breaking scale, a messenger mass, the μ -parameter and the gravitino mass in a minimal supersymmetric (SUSY) Standard Model (MSSM) are all explained by a single mass scale, a R-symmetry breaking scale. We focus on a low scale SUSY-breaking scenario with the gravitino mass m 3/2 = $$ \mathcal{O}(1)\mathrm{eV} $$ O 1 eV , which is free from the cosmological gravitino problem and relaxes the fine-tuning of the cosmological constant. Both the messenger and SUSY-breaking sectors are subject to a hidden strong dynamics with the conformality above the messenger mass threshold (and hence the name of the model “strongly interacting conformal gauge mediation”). In our model, the Higgs B-term is suppressed and a large tan β is predicted, resulting in the relatively light second CP-even Higgs and the CP-odd Higgs with a sizable production cross section. These Higgs bosons can be tested at future LHC experiments.
... Putting these VEVs into the superpotential in Eq. (14), the messenger fields obtain their masses and the mass splittings, As another example to enhance the Higgs boson mass, it is also possible to introduce vector-like matter fields coupling to the Higgs doublets [32][33][34][35][36][37][38][39][40]. In those extensions, however, the more the vector-like matters are added, the severer upper limit on the messenger number 7 See also [30] for another strongly interacting messenger model. 8 Here, we assume that the NMSSM respects the Z 2 symmetry. ...
... As an interesting aspect of the strongly coupled low-scale gauge mediation it may naturally provide dark matter candidate, the baryonic composite states in the SUSY breaking sector or the messenger sector [22,30,[50][51][52][53]. The baryonic composite states are given by higher dimensional operators, and hence, they couple to the SM particles very weakly. ...
... Thus, the final distribution should have a peak at around O(100) TeV, since the scale lower than O(100) TeV is not habitable. 11 Therefore, in this interpretation, the Higgs boson mass and rather heavy squark masses are outcomes of the cosmological selection on the dark matter density [30]. For some scenario, the effective annihilation cross section of baryonic composite states can exceed the unitarity limit on each partial wave modes [55]. ...
We revisit low-scale gauge mediation models in light of recent observations of CMB Lensing and Cosmic Shear which put a severe upper limit on the gravitino mass, $m_{3/2} \lesssim 4.7$eV. With such a stringent constraint, many models of low-scale gauge mediation are excluded when the squark masses are required to be rather large to explain the observed Higgs boson mass. In this note, we discuss a type of low-scale gauge mediation models which satisfy both the observed Higgs boson mass and the upper limit on the gravitino mass. We also show that the gravitino mass cannot be smaller than about 1eV even in such models, which may be tested in future observations of 21 cm line fluctuations.
... For explicit models realizing this situation, we have the conformal gauge mediation models discussed in Refs. [43,44,45,46,47] in mind. ...
... We should note, here, that there is an excellent possibility on the DM candidate in strongly coupled low scale gauge mediation models [61,62,63,64,47]. ...
We consider low scale gauge mediation models with a very light gravitino
m_{3/2}~16 eV, in the light of recent experimental hints on the Higgs boson
mass. The light gravitino is very interesting since there is no gravitino
over-production problem, but it seems difficult to explain the Higgs boson mass
of ~125 GeV. This is because of the conflict between the light gravitino mass
and heavy SUSY particle masses needed for producing the relatively heavy Higgs
boson mass. We consider two possible extensions in this paper: a singlet
extension of the Higgs sector, and strongly coupled gauge mediation. We show
that there is a large parameter space, in both scenarios, where the Higgs boson
mass of ~125 GeV is explained without any conflict with such a very light
gravitino.
... See, e.g., Refs. [114][115][116] for a detailed discussion of such scenarios in different contexts. However, it is expected that the length of cosmic strings cannot be sufficiently long but suppressed by some power of number density of quarks if quarks and antiquarks present in the thermal plasma at the deconfinement/confinement phase transition. ...
We discuss the formation of cosmic strings or macroscopic color flux tubes at the phase transition from the deconfinement to confinement phase in pure Yang–Mills (YM) theory, such as SU(N), Sp(N), SO(N), and Spin(N), based on the current understanding of theoretical physics. According to the holographic dual descriptions, the cosmic strings are dual to fundamental strings or wrapped D-branes in the gravity side depending on the structure of the gauge group, and the reconnection probability is suppressed by O(N−2) and e−O(N), respectively. The pure YM theory thus provides a simple realization of cosmic F- and D-strings without the need for a brane-inflationary scenario or extra dimension. We also review the stability of cosmic strings based on the concept of 1-form symmetry, which further implies the existence of a baryon vertex in some YM theory. We calculate the gravitational wave spectrum that is emitted from the cosmic strings based on an extended velocity-dependent one-scale model and discuss its detectability based on ongoing and planned gravitational-wave experiments. In particular, the SKA and LISA can observe gravitational signals if the confinement scale is higher than O(1012) GeV and O(1010) GeV for SU(N) with N=O(1), respectively.
... The quark mass can be naturally of the same order as Λ by a mechanism similar to that discussed in Refs. [45][46][47], in which case the lifetime of a string can be shorter than the present age of the Universe. Such decaying cosmic strings have gained significant attention in recent works [48][49][50]. ...
We discuss the formation of cosmic strings or macroscopic color flux tubes after the deconfinement/confinement phase transition in the pure Yang-Mills theory. Based on holographic dual descriptions, these cosmic strings can be interpreted as fundamental (F-) strings or wrapped D-branes (which we call as D-strings) in the gravity side, depending on the structure of the gauge group. In fact, the reconnection probabilities of the F- and D-strings are suppressed by factors of $1/N^2$ and $e^{-c N}$, where $c = \mathcal{O}(1)$, in a large-$N$ limit, respectively. Supported by the picture of electric-magnetic duality, we discuss that color flux tubes form after the deconfinement/confinement phase transition, just like the formation of local cosmic strings after spontaneous symmetry breaking in the weak-U(1) gauge theory. We use an extended velocity-dependent one-scale model to describe the dynamics of the string network and calculate the gravitational wave signals from string loops.
... Refs. [111][112][113] for a detailed discussion of such scenarios in different contexts. ...
We discuss the formation of cosmic strings or macroscopic color flux tubes at the phase transition from the deconfinement to confinement phase in pure Yang-Mills (YM) theory, such as SU($N$), Sp($N$), SO($N$), and Spin($N$), based on the current understanding of theoretical physics. According to the holographic dual descriptions, the cosmic strings are dual to fundamental strings or wrapped D-branes in the gravity side depending on the structure of the gauge group, and the reconnection probability is suppressed by $\mathcal{O}(N^{-2})$ and $e^{-\mathcal{O}(N)}$, respectively. The pure YM theory thus provides a simple realization of cosmic F- and D-strings without the need for a brane-inflationary scenario or extra dimension. We also review the stability of cosmic strings based on the concept of 1-form symmetry, which further implies the existence of a baryon vertex in some YM theory. We calculate the gravitational wave spectrum that is emitted from the cosmic strings based on an extended velocity-dependent one-scale model and discuss its detectability based on ongoing and planned gravitational-wave experiments. In particular, the SKA and LISA can observe gravitational signals if the confinement scale is higher than $\mathcal{O}(10^{12})\,\mathrm{GeV}$ and $\mathcal{O}(10^{10})\,\mathrm{GeV}$ for SU($N$) with $N = \mathcal{O}(1)$, respectively.
... A non-minimal Higgs sector or strongly coupled messengers may achieve m 3/2 16 eV [17], but it is unclear if the gravitino mass can be pushed below 4.7 eV. These problems can be ameliorated by using the Next-to-Minimal Supersymmetric Standard Model (NMSSM) or Dirac-NMSSM [18], coupling the Higgs to messengers [19], or having a strongly coupled messenger sector [20][21][22][23]. However, these models are quite intricate. ...
A recent cosmological bound on the gravitino mass, $m_{3/2}<4.7$ eV, together with LHC results on the Higgs mass and direct searches, excludes minimal gauge mediation with high reheating temperatures. We discuss a minimal, vector-mediated model which incorporates the seesaw mechanism for neutrino masses, allows for thermal leptogenesis, ameliorates the $\mu$ problem, and achieves the observed Higgs mass and a gravitino as light as $1$-$2$ eV.
... We should also mention that there have been several attempts in the literature to solve the question of the most probable SUSY scale by imposing further restrictions on the landscape of vacua for habitability. For example, the habitability condition has been used to restrict the landscape of vacua based on the abundance of dark matter in [22,23,24], which leads to a sharp lower cut-off for the distribution of m SUSY . 6 In this paper, we shall refer to this type of restriction of the landscape based on the requirement of habitability as cosmological selection. ...
We discuss a possible answer to the fundamental question of why nature would
actually prefer low-scale supersymmetry, but end up with a supersymmetry scale
that is not completely natural. This question is inevitable if we postulate
that low-energy supersymmetry is indeed realized in nature, despite the null
observation of superparticles below a TeV at the Large Hadron Collider. As we
argue in this paper, superparticles masses in the multi-TeV range can, in fact,
be reconciled with the concept of naturalness by means of a cosmological
selection effect--a selection effect based on the assumption of an exact
discrete R-symmetry that is spontaneously broken by gaugino condensation in a
pure supersymmetric Yang-Mills theory. In such theories, the dynamical scale of
the Yang-Mills gauge interactions is required to be higher than the
inflationary Hubble scale, in order to avoid the formation of domain walls.
This results in a lower limit on the superparticle masses and leads us to
conclude that, according to the idea of naturalness, the most probable range of
superparticle masses is potentially located at the multi-TeV, if the
inflationary Hubble rate is of O(10^{14}) GeV. Our argument can be partially
tested by future measurements of the tensor fraction in the Cosmic Microwave
Background fluctuations.
... When m 3/2 1 keV, the gravitino does not overclose the Universe, but would be a warm dark matter component, ruled out by the Lyman-α forest data unless m 3/2 16 eV [10]. The tension may be eased if the Higgs sector is extended to the NMSSM or Dirac-NMSSM [11], if the messenger sector couples to the Higgs [12], or is strongly coupled [13][14][15][16]. However, these models are somewhat more complicated. ...
In models of low-energy gauge mediation, the observed Higgs mass is in
tension with the cosmological limit on the gravitino mass $m_{3/2} \lesssim 16$
eV. We present an alternative mediation mechanism of supersymmetry breaking via
a $U(1)$ $D$-term with an $E_6$-inspired particle content, which we call
"vector mediation". The gravitino mass can be in the eV range. The sfermion
masses are at the 10 TeV scale, while gauginos around a TeV. This mechanism
also greatly ameliorates the $\mu$-problem.
... Such a cold and stable particle can be the QCD axion [28][29][30] or the composite baryons in the SUSY breaking, or can also be generated in the messenger sector in models with strongly coupled low scale gauge mediation [31][32][33][34]. ...
We explore the discovery potential of light gravitino mass m
3/2 by combining future cosmology surveys and collider experiments. The former probe the imprint of light gravitinos in the cosmic matter density field, whereas the latter search signatures of a supersymmetry breaking mechanism. Free-streaming of light gravitinos suppresses the density fluctuations at galactic and sub-galactic length scales, where weak gravitational lensing can be used as a powerful probe. We perform numerical simulations of structure formation to quantify the effect. We then run realistic ray-tracing simulations of gravitational lensing to measure the cosmic shear in models with light gravitino. We forecast the possible reach of future wide-field surveys by Fisher analysis; the light gravitino mass can be determined with an accuracy of m
3/2 = 4 ± 1 eV by a combination of the Hyper Suprime Cam survey and cosmic microwave background anisotropy data obtained by Planck satellite. The corresponding accuracy to be obtained by the future Large Synoptic Survey Telescope is δm
3/2 = 0.6 eV. Data from experiments at Large Hadron Collider at 14 TeV will provide constraint at m
3/2 ≃ 5 eV in the minimal framework of gauge-mediated supersymmetry breaking (GMSB) model. We conclude that a large class of the GMSB model can be tested by combining the cosmological observations and the collider experiments.
... This observed Higgs mass, together with non-discovery of superpartners at LHC, suggests that the supersymmetry (SUSY) breaking scale is much higher than we expected, say above O(10) TeV [2]. However, if the SUSY is a solution to the hierarchy problem and hence its breaking is biased toward low energy scales, a crucial question naturally arises ; why does nature choose such a high energy scale for the SUSY breaking [3]? We show, in this letter, that the pure gravity mediation model recently proposed to explain the 125 GeV Higgs mass [4] (for a similar model, see also [5]) provides us with a possible explanation for the high scale SUSY breaking if the topological inflation is the last inflation in the early universe. ...
The recently observed mass ~ 125 GeV for the Higgs boson suggests a
high-energy scale SUSY breaking, above O(10) TeV. It is, however, very puzzling
why nature chooses such a high energy scale for the SUSY breaking, if the SUSY
is a solution to the hierarchy problem. We show that the pure gravity mediation
provides us with a possible solution to this puzzle if the topological
inflation is the last inflation in the early universe. We briefly discuss a
chaotic inflation model in which a similar solution can be obtained.
We discuss the formation of cosmic strings or macroscopic color flux tubes after the deconfinement/confinement phase transition in the pure Yang–Mills theory. Based on holographic dual descriptions, these cosmic strings can be interpreted as fundamental (F-) strings or wrapped D-branes (which we call as D-strings) in the gravity side, depending on the structure of the gauge group. In fact, the reconnection probabilities of the F- and D-strings are suppressed by factors of 1/N2 and e−cN, where c=O(1), in a large-N limit, respectively. Supported by the picture of electric–magnetic duality, we discuss that color flux tubes form after the deconfinement/confinement phase transition, just like the formation of local cosmic strings after spontaneous symmetry breaking in the weak-U(1) gauge theory. We use an extended velocity-dependent one-scale model to describe the dynamics of the string network and calculate the gravitational wave signals from string loops. We also discuss the dependence on the size of produced string loops.
We propose a new class of models with gauge mediated supersymmetry breaking, the cascade supersymmetry breaking. This class of models is consistent with the gravitino mass as low as O(1)eV without having suppressed gaugino masses, nor the Landau pole problems of the gauge coupling constants of the Standard Model below the scale of the grand unification. In particular, there is no supersymmetric vacuum in the vicinity of the supersymmetry breaking vacuum even for such a low gravitino mass. Thus, the model does not have a vacuum stability problem decaying into supersymmetric vacua. Comment: 27 pages, 3 figures
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 mu2≪Bmu if at the same time Bmu≪mHd2. 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 phenomenological predictions for the spectrum of superparticles.
We provide a method for obtaining simple models of supersymmetry breaking, with all small mass scales generated dynamically, and illustrate it with explicit examples. We start from models of perturbative supersymmetry breaking, such as O’Raifeartaigh and Fayet models, that would respect an R symmetry if their small input parameters transformed as the superpotential does. By coupling the system to a pure supersymmetric Yang-Mills theory (or a more general supersymmetric gauge theory with dynamically small vacuum expectation values), these parameters are replaced by powers of its dynamical scale in a way that is naturally enforced by the symmetry. We show that supersymmetry breaking in these models may be straightforwardly mediated to the supersymmetric standard model, obtain complete models of direct gauge mediation, and comment on related model building strategies that arise in this simple framework.
We propose a one-parameter theory for gauge mediation of supersymmetry (SUSY) breaking. The spectrum of SUSY particles such as squarks and sleptons in the SUSY standard-model and the dynamics of SUSY-breaking sector are, in principle, determined only by one parameter in the theory, that is, the mass of messengers. Above the messenger threshold all gauge coupling and Yukawa coupling constants in the SUSY-breaking sector are on the infrared fixed point. We find that the present theory may predict a split spectrum of the standard-model SUSY particles, mgaugino<msfermion, where mgaugino and msfermion are SUSY-breaking masses for gauginos and squarks/sleptons, respectively.
We extend the “naïve dimensional analysis” arguments used in QCD for estimating the strengths of operators in chiral Lagrangians to strongly coupled supersymmetric theories. In particular, we show how to count factors of 4π — an inexact science, but nevertheless a useful art when such theories are used to model real particle physics.
In gauge-mediated theories supersymmetry breaking originates in a strongly interacting sector and is communicated to the ordinary sparticles via SU(3)×SU(2)×U(1) carrying “messenger” particles. Stable baryons of the strongly interacting supersymmetry breaking sector naturally weigh ∼ 100 TeV and are viable cold dark matter candidates. They interact too weakly to be observed in dark matter detectors. The lightest messenger particle is a viable cold dark matter candidate under particular assumptions. It weighs less than 5 TeV, has zero spin and is easily observable in dark matter detectors.
Light gravitinos, with mass in the eV to MeV range, are well-motivated in
particle physics, but their status as dark-matter candidates is muddled by
early-Universe uncertainties. We investigate how upcoming data from colliders
may clarify this picture. Light gravitinos are produced primarily in the decays
of the next-to-lightest supersymmetric particle, resulting in spectacular
signals, including di-photons, delayed and non-pointing photons, kinked charged
tracks, and heavy metastable charged particles. We find that the Tevatron with
20/fb and the 7 TeV LHC with 1/fb may both see evidence for hundreds of
light-gravitino events. Remarkably, this collider data is also well suited to
distinguish between currently viable light-gravitino scenarios, with striking
implications for structure formation, inflation, and other early-Universe
cosmology.
We consider explicit models of dynamical supersymmetry breaking where dark matter is
a 10 – 100 TeV strongly-interacting composite state carrying no standard model quantum
numbers. These constructions are simple variants of well-known supersymmetry breaking
mechanisms, augmented to allow for a large “flavor” symmetry. Dark matter is the lightest
composite modulus charged under this symmetry and is a viable cold dark matter candidate
with a thermal relic abundance. This is an attractive possibility in low-scale gauge-mediated
scenarios where the gravitino is the lightest superparticle. A light R-axion associated with
supersymmetry breaking is present in these hidden sectors and serves as the portal between
dark matter and the standard model. Such scenarios are relevant for present and future
indirect detection experiments.
We study dynamical supersymmetry breaking in vector-like superconformal N=1
gauge theories. We find appropriate deformations of the superpotential to
overcome the problem of the instability of the non supersymmetric vacuum. The
request for long lifetime translates into constraints on the physical couplings
which in this regime can be controlled through efficient RG analysis.
We investigate supersymmetric models for dark matter which is represented by pseudomoduli in weakly coupled hidden sectors. We propose a scheme to add a dark matter sector to quiver gauge theories with metastable supersymmetry breaking. We discuss the embedding of such scheme in string theory and we describe the dark matter sector in terms of D7 flavour branes. We explore the phenomenology in various regions of the parameters. Comment: 24 pages, 12 figures, JHEP3.cls
We prove a general bound on the superpotential in theories with broken supersymmetry and broken R-symmetry, |〈W〉| < \( \frac{1}{2} \)
f
a
F, where f
a
and F are the R-axion and Goldstino decay constants, respectively. The bound holds for weakly coupled as well as strongly coupled theories, thereby providing an exact result in theories with broken supersymmetry. We briefly discuss several possible applications.
We consider candidates for dark matter in models of gauge mediated supersymmetry breaking, in which the supersymmetry breaking sector is weakly coupled and calculable. Such models typically contain classically flat directions, that receive one-loop masses of a few TeV. These pseudo-flat directions provide a new mechanism to account for the cold dark matter relic abundance. We discuss also the possibility of heavy gravitino dark matter in such models. Comment: 16 pages, 2 figures. v2: comments, refs added
We present a model in which supersymmetry is dynamically broken at comparatively low energies. Previous efforts to construct simple models of this sort have been hampered by the presence of axions. The present model, which exploits an observation of Bagger, Poppitz, and Randall to avoid this problem, is far simpler than previous constructions. Models of this kind do not suffer from the naturalness difficulties of conventional supergravity models, and make quite definite predictions for physics over a range of scales from 100’s of GeV to 1000’s of TeV. Thus ‘‘renormalizable visible sector models’’ are a viable alternative to more conventional approaches. Our approach also yields a viable example of hidden sector dynamical supersymmetry breaking.
We discuss a class of gauge mediated supersymmetry breaking models with conformal invariance above the messenger mass scale (conformal gauge mediation). The spectrum of the supersymmetric particles including the gravitino is uniquely determined by the messenger mass. When the conformal fixed point is strongly interacting, it predicts a light gravitino of mass m3/2<O(10) eVm3/2<O(10) eV, which is attractive since such a light gravitino causes no problem in cosmology.
We investigate gauge coupling unification at 2-loops for theories with 5 extra vectorlike SU(5) fundamentals added to the minimal supersymmetric standard model (MSSM). This is a borderline case where unification is only predicted in certain regions of parameter space. We establish a lower bound on the scale for the masses of the extra flavors, as a function of the sparticle masses. Models far outside of the bound do not predict unification at all (but may be compatible with unification), and models outside but near the boundary cannot reliably claim to predict it with an accuracy comparable to the MSSM prediction. Models inside the boundary can work just as well as the MSSM.
We provide, in a framework of vectorlike gauge theories, concrete models for conformal sequestering of dynamical supersymmetry (SUSY) breaking in the hidden sector. If the sequestering is sufficiently strong, anomaly mediation of the SUSY breaking may give dominant contributions to the mass spectrum of SUSY standard model particles, leading to negative slepton masses squared. Thus, we also consider a model with gravitational gauge mediation to circumvent the tachyonic slepton problem in pure anomaly-mediation models.
A new class of models of dynamical supersymmetry breaking is proposed. The models are based on SU(NC) gauge theories with NF(<NC) flavors of quarks and singlets. Dynamically generated superpotential exhibits runaway behavior. By embedding the models into conformal field theories at high energies, the runaway potential is stabilized by strong quantum corrections to the Kähler potential. The quantum corrections are large but nevertheless can be controlled due to superconformal symmetry of the theories.
Direct gauge mediation models using the Intriligator-Seiberg-Shih metastable vacua suffer from the Landau pole problem of the standard-model gauge couplings and the existence of R-symmetry forbidding gaugino masses. These problems may be solved by using the recently proposed supersymmetry (SUSY)-breaking models in a conformal window of the vectorlike SU(NC) gauge theory with gauge singlets. In this paper we propose a model of gauge mediation based on the SUSY-breaking model in the conformal window, and study the dynamics for SUSY breaking. In this model, there are massive vectorlike bifundamental fields charged under both SU(NC) and the standard-model gauge group, and our model can be regarded as a semidirect gauge mediation model. The color number NC can be small to avoid the Landau pole problem, and R symmetry is also broken under a reasonable assumption on the strong dynamics of the model. The model possesses only one free parameter, and the gaugino and sfermion masses are naturally of the same order.
A supersymmetric model of particle physics is developed whose
phenomenology closely resembles that of supersymmetric technicolor
models.
On leave to the Belgian Army until May 1, 1982.
We describe a class of supersymmetric SU(3)×SU(2)×U(1) models where all quarks and leptons, as well as their scalar partners, get masses through one-loop radiative corrections.
We discuss the problem of constructing a model in which supersymmetry is unbroken down to low energies. It is suggested that the scalar partners of quarks and leptons may get their masses through radiative corrections and that the breaking of the weak interactions also occurs through radiative corrections. A toy model is constructed which illustrates these ideas.
The massless limit of supersymmetric QCD with flavors and N colors is analyzed in detail. For there is a unique superpotential which might be generated by non-perturbative effects. We show that it indeed appears, thus violating the non-renormalization theorems. For instantons produce the superpotential. For it is again generated, provided that a mild assumption about the dynamics of pure supersymmetric gauge theories is correct. For no invariant superpotential exists; the classical vacuum degeneracy is a property of the full quantum theory. When a small quark mass term is added to the theory supersymmetric ground states, identified with those found by Witten exist. As m → 0 these N vacua wander to infinity, leaving the massless theory without a ground state.
It is now established that the non-renormalization theorems are violated by non-perturbative effects in many four-dimensional supersymmetric theories, and that dynamical supersymmetry-breaking (DSB) occurs in some chiral gauge theories. Here we presenr a set of general techniques which allow one to determine whether or not supersymmetry is broken in almost any theory, and permit a quite detailed analysis of the dynamics of many theories. These techniques are illustrated by analysis of a wide variety of instructive models, including one in which DSB occurs and in which we compute the spectrum and ground state energy. A careful discussion of the prospects for realistic model building is presented, including: an argument that additional gauge interactions are required to build realistic theories; dynamical supersymmetry-breaking in N = 1 supergravity theories; a detailed discussion of the problems and prospects for dynamical supersymmetry-breaking in the multi-TeV energy range.
We point out that thermal relic abundance of the dark matter is strongly altered by a non-perturbative effect called the Sommerfeld enhancement, when constituent particles of the dark matter are non-singlet under the SU(2)L gauge interaction and much heavier than the weak gauge bosons. Typical candidates for such dark matter particles are the heavy wino- and higgsino-like neutralinos. We investigate the non-perturbative effect on the relic abundance of dark matter for the wino-like neutralino as an example. We show that its thermal abundance is reduced by 50% compared to the perturbative result. The wino-like neutralino mass consistent with the observed dark matter abundance turns out to be 2.7 TeV≲m≲3.0 TeV.
A discrete R-symmetry often appears as an exact gauge symmetry in the low energy effective theory of superstring theories. We search for such discrete R-symmetries from a phenomenological point of view and find that Z9R and Z18R are candidates of the nonanomalous R-symmetry in the case of the minimal supersymmetric standard model. We also find Z4R and Z20R in the case that quarks and leptons are embedded in the SU(5) GUT multiplets. Interesting is that in the latter case all the solutions predict some extra matter multiplets and we find that the simplest choice of the extra matters is to take a pair of and of SU(5)GUT whose mass is of order the SUSY breaking scale ∼1 TeV. We emphasize that the presence of such extra matters is testable in future hadron collider experiments.
A baryonic bound state with a mass of O(100) TeV, which is composed of strongly interacting messenger quarks in the low scale gauge mediation, can naturally be the cold dark matter. Interestingly, we find that such a baryonic dark matter is generically metastable, and the decay of this dark matter can naturally explain The origin and nature of the dark matter (DM) are one of the most challenging problems in the particle physics and cosmology. If the DM is in thermal equilibrium in the early universe, the present abundance of the DM is determined by its annihilation cross section σvrel. Here, vrel is the relative velocity of the DM at the freeze out time. The observed DM
Among various supersymmetric (SUSY) models, gauge-mediated SUSY breaking models with an ultra-light gravitino of mass m3/2≲O(10) eV are very attractive, since they are completely free from notorious gravitino problems. A drawback of such a scenario is the absence of the supersymmetric cold dark matter. In this Letter, we propose that a baryonic bound state of strongly interacting messenger particles, with a mass of O(100) TeV, can naturally be the cold dark matter. We also exemplify a model which realizes such a scenario.
We point out that the μ-problem in theories in which supersymmetry breaking is communicated to the observable sector by gauge interactions is more severe than the one encountered in the conventional gravity-mediated scenarios. The difficulty is that once μ is generated by a one-loop diagram, then usually Bμ is also generated at the same loop order. This leads to the problematic relation Bμtμ wheret 10–100 TeV is the effective supersymmetry-breaking scale. We 0 present a class of theories for which this problem is naturally solved. Here, without any fine tuning among parameters, μ is generated at one loop, while Bμ arises only at the two-loop level. This mechanism can naturally lead to an interpretation of the Higgs doublets as pseudo-Goldstone bosons of an approximate global symmetry.
In models where supersymmetry breaking is communicated into the visible sector via gauge interactions the lightest supersymmetric particle is typically the gravitino which is too light to account for cold dark matter. We point out that the lightest messenger sneutrinos with mass in the range of one to three TeV may serve as cold dark matter over most of the parameter space due to one-loop electroweak radiative corrections. However, in the minimal model this mass range has been excluded by the direct dark matter searches. We propose a solution to this problem by introducing terms that explicitly violate the messenger number. This results in low detection rate for both direct and indirect searches and allows messenger sneutrinos to be a valid dark matter candidate in a wide region of SUSY parameter space.
General conditions for dynamical supersymmetry breaking are discussed. Very small effects that would usually be ignored, such as instantons of a grand unified theory, might break supersymmetry at a low energy scale. Examples are given (in 0 + 1 and 2 + 1 dimensions) in which dynamical supersymmetry breaking occurs. Difficulties that confront such a program in four dimensions are described.
We propose new types of theories which combine supersymmetry and some new strong interaction which we generically refer to as supercolor. In some cases which we discuss, supercolor is identical with the familiar technicolor. These theories are natural. They explain the scale of weak interactions and they do not require any unnatural adjustments. They possess naturally light scalars which give mass to ordinary quarks and leptons.Naturalness imposes strong constraints on the U(1) gauge structure of the theory. These constraints appear not to be satisfied by the electro-weak hypercharge. If this is true then, the symmetry of the world at energies above ∼1 TeV cannot be standard SU(3)C×SU(2)L×U(1)Y with only ordinary families.
We demonstrate electric-magnetic duality in N = 1 supersymmetric non-Abelian gauge theories in four dimensions by presenting two different gauge theories (different gauge groups and quark representations) leading to the same non-trivial long distance physics. The quarks and gluons of one theory can be interpreted as solitons (non-Abelian magnetic monopoles) of the elementary fields of the other theory. The weak coupling region of one theory is mapped to a strong coupling region of the other. When one of the theories is Higgsed by an expectation value of a squark, the other theory is confined. Massless glueballs, baryons and Abelian magnetic monopoles in the confining description are the weakly coupled elementary quarks (i.e. solitons of the confined quarks) in the dual Higgs description.
We present one approach for solving the gauge hierarchy problem in a grand unified supersymmetric theory. Supersymmetry is broken at a scale of order 1012 GeV. Both the grand scale (∼1019 GeV) and the weak scale are generated via radiative corrections. The main phenomenological features of the model are: (i) the proton decays into and the neutron decays into ; (ii) the strong GP problem is solved with an invisible axion; (iii) the superpartners of quarks, leptons, gauge and Higgs bosons have masses ∼ 50–100 GeV; and (iv) the lightest superpartner is stable.
We propose a supersymmetric model of particle physics in which supersymmetry is broken dynamically by strong gauge forces. The model, as it stands, requires that one parameter be fine tuned; a grand unified version would not require any fine tuning. The model has no strong CP problem, and agrees with all known particle physics experiments. A variety of new particles, many of which weigh less than 100 GeV, are predicted.
Discrete R symmetries are interesting from a variety of points of view. They raise the specter, however, of domain walls, which may be cosmologically problematic. In this note, we describe some of the issues. In many schemes for supersymmetry breaking, as we explain, satisfying familiar constraints such as suppression of gravitino production, insures that the domain walls are readily inflated away. However, in others, they form after inflation. In these cases, it is necessary that they annihilate. We discuss possible breaking mechanisms for the discrete symmetries, and the constraints they must satisfy so that the walls annihilate effectively. Comment: 13 pages
Very light gravitino scenario m_{3/2} < 16 eV is very interesting, since there is no cosmological problem. However in such a scenario, stability of the vacuum is an important issue. Recently, Yonekura and one of the authors RS have investigated the parameter space of a low scale gauge mediation with a perturbatively stable vacuum and found that there are severe upper bound on the gaugino masses. In this paper, we show that such a model can be completely excluded/discovered at very early stage of the LHC run. Comment: 10 pages, 1 figure; v2: minor collections
A large class of non-minimal gauge mediation models, such as (semi-)direct
gauge mediation, predict a hierarchy between the masses of the supersymmetric
standard model gauginos and those of scalar particles. We perform a
comprehensive study of these non-minimal gauge mediation models, including mass
calculations in semi-direct gauge mediation, to illustrate these features, and
discuss the phenomenology of the models. We point out that the cosmological
gravitino problem places stringent constraints on mass splittings, when the
Bino is the NLSP. However, the GUT relation of the gaugino masses is broken
unlike the case of minimal gauge mediation, and an NLSP other than the Bino
(especially the gluino NLSP) becomes possible, relaxing the cosmological
constraints. We also discuss the collider signals of the models.
We discuss theories of gauge mediation in which the hidden sector consists of
two subsectors which are weakly coupled to each other. One sector is made up of
messengers and the other breaks supersymmetry. Each sector by itself may be
strongly coupled. We provide a unifying framework for such theories and discuss
their predictions in different settings. We show how this framework
incorporates all known models of messengers. In the case of weakly-coupled
messengers interacting with spurions through the superpotential, we prove that
the sfermion mass-squared is positive, and furthermore, that there is a lower
bound on the ratio of the sfermion mass to the gaugino mass.
After reviewing the theoretical, phenomenological and experimental motivations for supersymmetric extensions of the Standard Model, we recall that supersymmetric relics from the Big Bang are expected in models that conserve R parity. We then discuss possible supersymmetric dark matter candidates, focusing on the lightest neutralino and the gravitino. In the latter case, the next-to-lightest supersymmetric particle is expected to be long-lived, and possible candidates include spartners of the tau lepton, top quark and neutrino. We then discuss the roles of the renormalization-group equations and electroweak symmetry breaking in delimiting the supersymmetric parameter space. We discuss in particular the constrained minimal extension of the Standard Model (CMSSM), in which the supersymmetry-breaking parameters are assumed to be universal at the grand unification scale, presenting predictions from a frequentist analysis of its parameter space. We also discuss astrophysical and cosmological constraints on gravitino dark matter models, as well as the parameter space of minimal supergravity (mSUGRA) models in which there are extra relations between the trilinear and bilinear supersymmetry-breaking parameters, and between the gravitino and scalar masses. Finally, we discuss models with non-universal supersymmetry-breaking contributions to Higgs masses, and models in which the supersymmetry-breaking parameters are universal at some scale below that of grand unification. http://cambridge.org/us/catalogue/catalogue.asp?isbn=9780521763684 Comment: 38 pages, 10 figures
In recent works, we have proposed a possible dark matter in composite messenger gauge mediation models. In this paper, we discuss the details of a composite messenger model taking a possible supersymmetry breaking scenario and show that the correct dark matter abundance and a successful gauge mediation can be realized. Comment: 18 pages, 3 figures
We propose a mechanism for relaxing a constraint on the number of messengers
in low-scale gauge mediation models. The Landau pole problem for the
standard-model gauge coupling constants in the low-scale gauge mediation can be
circumvented by using our mechanism. An essential ingredient is a large
positive anomalous dimension of messenger fields given by a large Yukawa
coupling in a conformal field theory at high energies. The positive anomalous
dimension reduces the contribution of the messengers to the beta function of
the standard-model gauge couplings.
If nature exhibits low energy supersymmetry, discrete (non-$Z_2$) R symmetries may well play an important role. In this paper, we explore such symmetries. We generalize gaugino condensation, constructing large classes of models which are classically scale invariant, and which spontaneously break discrete R symmetries (but not supersymmetry). The order parameters for the breaking include chiral singlets. These simplify construction of models with metastable dynamical supersymmetry breaking. We explain that in gauge mediation, the problem of the cosmological constant makes "retrofitting" particularly natural -- almost imperative. We describe new classes of models, with interesting scales for supersymmetry breaking, and which allow simple solutions of the $\mu$ problem. We argue that models exhibiting such R symmetries can readily solve not only the problem of dimension four operators and proton decay, but also dimension five operators. On the other hand, in theories of "gravity mediation", the breaking of R symmetry is typically of order $M_p$, R parity is required to suppress dimension four $B$ and $L$ violating operators, and dimension five operators remain problematic. Comment: 17 pages, latex; references to earlier work added; typos fixed, minor corrections and revisions, journal version
We discuss the cosmic ray spectra in
annihilating/decaying Nambu-Goldstone dark matter models.
The recent observed positron/electron excesses at PAMELA and Fermi experiments
are well fitted by the dark matter with a mass of 3 TeV for the annihilating model, while
with a mass of 6 TeV for the decaying model.
We also show that the Nambu-Goldstone dark matter models predict
a distinctive gamma-ray spectrum in a certain parameter space.
We point out that pseudomoduli -- tree-level flat directions that often accompany dynamical supersymmetry breaking -- can be natural candidates for TeV-scale dark matter in models of gauge mediation. The idea is general and can be applied to different dark matter scenarios, including (but not limited to) those of potential relevance to recent cosmic ray anomalies. We describe the requirements for a viable model of pseudomoduli dark matter, and we analyze two example models to illustrate the general mechanism -- one where the pseudomoduli carry Higgsino-like quantum numbers, and another where they are SM singlets but are charged under a hidden-sector $U(1)'$ gauge group. Comment: 20 pages, refs added
Supersymmetric (SUSY) standard models in which the lightest SUSY particle (LSP) is an ultralight gravitino (m_{3/2}=O(1) eV) are very attractive, since they are free from the cosmological gravitino problems. If the neutralino is the next lightest SUSY particle (NLSP), it decays into a photon and the gravitino in collider experiments. We propose a simple test for the lightness of gravitino at the LHC. Comment: 9 pages, 2 figures
Cosmologically long-lived, composite states arise as natural dark matter candidates in theories with a strongly interacting hidden sector at a scale of 10 - 100 TeV. Light axion-like states, with masses in the 1 MeV - 10 GeV range, are also generic, and can decay via Higgs couplings to light standard model particles. Such a scenario is well motivated in the context of very low energy supersymmetry breaking, where ubiquitous cosmological problems associated with the gravitino are avoided. We investigate the astrophysical and collider signatures of this scenario, assuming that dark matter decays into the axion-like states via dimension six operators, and we present an illustrative model exhibiting these features. We conclude that the recent data from PAMELA, FERMI, and H.E.S.S. points to this setup as a compelling paradigm for dark matter. This has important implications for future diffuse gamma ray measurements and collider searches. Comment: 40 pages, 7 figures; references and comments added
Supersymmetric models with spontaneously broken approximate R-symmetry contain a light spin 0 particle, the R-axion. The properties of the particle can be a powerful probe of the structure of the new physics. In this paper, we discuss the possibilities of the R-axion detection at the LHC experiments. It is challenge to observe this light particle in the LHC environment. However, for typical values in which the mass of the R-axion is a few hundred MeV, we show that those particles can be detected by searching for displaced vertices from R-axion decay. Comment: 20 pages, 4 figures, minor corrections, references added
Supersymmetric SU(NC) gauge theories possess runaway-type superpotentials for NF < NC, where NF is the flavor number of massless quarks. We show that the runaway behavior can be stabilized for NF ≃ NC by introducing singlets with the aid of perturbative corrections to the Kähler potential, generating (local) minima It is well known that in a supersymmetric (SUSY) QCD based on an SU(NC) gauge theory with NF flavors of quarks Q and antiquarks ˜ Q [1], the dynamically generated superpotential implies a runaway behavior for NF < NC. In this theory we have SUSYinvariant vacua in the limit of meson fields |Q ˜ Q | → ∞. This is consistent with Witten
We propose a model of dark matter identified with a pseudo-Nambu-Goldstone boson in the dynamical supersymmetry breaking sector in a gauge mediation scenario. The dark matter particles annihilate via a below-threshold narrow resonance into a pair of R-axions each of which subsequently decays into a pair of light leptons. The Breit-Wigner enhancement explains the excess electron and positron fluxes reported in the recent cosmic ray experiments PAMELA, ATIC and PPB-BETS without postulating an overdensity in halo, and the limit on anti-proton flux from PAMELA is naturally evaded. Comment: 3 figures
We address the mu-problem in the context of General Gauge Mediation (GGM). We classify possible models depending on the way the Higgs fields couple to the supersymmetry breaking hidden-sector. The different types of models have distinct signatures in the MSSM parameters. We find concrete and surprisingly simple examples based on messengers in each class. These examples lead to all the soft masses and a consistent Higgs-sector. Comment: 21 pages. v2: minor corrections. v3: added reference
Using partial wave unitarity and the observed density of the Universe, it is shown that a stable elementary particle which was once in thermal equilibrium cannot have a mass greater than 340 TeV. An extended object which was once in thermal equlibrium cannot have a radius less than 7.5 x 10(exp -7) fm. A lower limit to the relic abundance of such particles is also found.