Publications (53)184.36 Total impact
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ABSTRACT: We investigate characteristic features of realistic parameter choice for primordial inflation with supersymmetric Higgs inflaton as an example of particle physics inflation model. We discuss constraints from observational results and analyze the degree of fine tuning needed to induce slowroll inflation for wide range of soft supersymmetry breaking scale. The observed amplitude of density fluctuations implies that the minimal fine tuning for the combined electroweak scale and inflaton flatness predicts the spectral index of 0.9500.965, which includes the central value from observational data.  [Show abstract] [Hide abstract]
ABSTRACT: We consider a novel class of constraints on chiral superfields to obtain supersymmetric nonlinear sigma models in four spacetime dimensions, which strictly combine the internal symmetry breaking with spontaneous supersymmetry breaking. The resultant massless modes can be exclusively NambuGoldstone bosons without their complex partners and the goldstino that is charged under the internal symmetry. The massive modes show a peculiar relation among their masses and the scales of symmetry breakings.  [Show abstract] [Hide abstract]
ABSTRACT: We propose a supersymmetric extension of the standard model whose Higgs sector induces a spontaneous supersymmetry breaking by itself. Unlike the minimal extension, the current Higgs mass bound can be evaded even at the treelevel without the help of the soft breaking terms due to the usual hidden sector, as is reminiscent of the next to minimal case. We also have a possibly light pseudogoldstino in our visible sector in addition to extra Higgs particles, both of which stem from supersymmetry breaking dynamics. In such a setup of visible supersymmetry breaking, we may see a part of supersymmetry breaking dynamics rather directly in future experiments. 
Article: Gravitational Supersymmetry Breaking
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ABSTRACT: We consider supersymmetry breaking models with a purely constant superpotential in supergravity. The supersymmetry breaking is induced for the vanishing cosmological constant. As a hidden mediation sector of supersymmetry breaking, it naturally leads to a split spectrum in supersymmetric standard model. We also point out possible utility of our setup to construct nonlinear sigma model and/or FayetIliopouloslike term in broken supergravity.  [Show abstract] [Hide abstract]
ABSTRACT: We provide nonlinear realization of supergravity with an arbitrary number of supersymmetries by means of coset construction. The number of gravitino degrees of freedom counts the number of supersymmetries, which will be possibly probed in future experiments. We also consider goldstino embedding in the construction to discuss the relation to nonlinear realization with rigid supersymmetries. Comment: 19 pages  [Show abstract] [Hide abstract]
ABSTRACT: 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.  [Show abstract] [Hide abstract]
ABSTRACT: Strongly coupled semidirect gauge mediation models of supersymmetry breaking through massive mediators with standard model charges are investigated by means of composite degrees of freedom. Sizable mediation is realized to generate the standard model gaugino masses for a small mediator mass without breaking the Supersymmetry (SUSY) [1] is expected to be a crucial ingredient of basic laws in Nature. It is an attractive possibility that SUSY is broken at low energy within the experimental reach in the near future. Among others, lowenergy dynamics with gauge mediation between a hidden sector of SUSY breaking and the visible sector of SUSY standard  [Show abstract] [Hide abstract]
ABSTRACT: We study gaugino mass generation in the context of semidirect gauge mediation models, where the messengers are charged under both the hidden sector and the standard model gauge groups while they do not play important roles in dynamical supersymmetry breaking. We clarify the cancellation of the leading contributions of the supersymmetry breaking effects to the gaugino mass in this class of models in terms of the macroscopic effective theory of the hidden sector dynamics. We also consider how to retrofit the model so that we obtain the nonvanishing leading contribution to the gaugino mass.  [Show abstract] [Hide abstract]
ABSTRACT: Supersymmetric SU(NC) gauge theories possess runawaytype 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  [Show abstract] [Hide abstract]
ABSTRACT: We argue that the Polonyi problem can be avoided when our supersymmetrybreaking vacuum is surrounded by many supersymmetric vacua. We construct a dynamical class of supersymmetrybreaking models to demonstrate our point. These Theoretical landscape such as in string/M theory is expected to possess an enormous number of metastable vacua in addition to supersymmetric (SUSY) ones. With such vacua sufficiently longlived in hand, we are led to suspect that our SUSYbreaking state is indeed metastable.  [Show abstract] [Hide abstract]
ABSTRACT: Dynamical models of inflation are given with composite inflatons by means of massive supersymmetric gauge theory. Nearly flat directions and stable massive ones in the potential are identified and slowroll during inflation is examined. This kind of dynamical inflations may be ubiquitous in fundamental unified theory with supersymmetry, which should contain gauge theories for interactions of elementary particles.  [Show abstract] [Hide abstract]
ABSTRACT: We address an issue what kind of tuning realizes a flat potential for inflaton in supergravity. We restrict ourselves to the case that inflationary dynamics is not affected by separate supersymmetrybreaking effects, and consider examples of a single chiral superfield as an inflaton with its vacuum of the vanishing cosmological constant. The examples potentially include the cases of Polonyi field or righthanded Slowroll inflation [1] takes place when the potential is flat enough, which is realized through tuning the form of potential by symmetry or by hand. 1 In nonsupersymmetric or supersymmetrybroken 2 cases, the required tuning is rather straightforward to flatten a potential with the kinetic term intact. On the other hand, in the supersymmetryinvariant 
Article: Marginally Eternal Inflation
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ABSTRACT: We examine the amount of parameter tuning to make slowroll inflation marginally eternal by considering an Rinvariant chaotic inflation as an example of oneparameter tuning in supergravity. The primordial inflation turns out to be possibly marginal in such a setup.  [Show abstract] [Hide abstract]
ABSTRACT: We consider an inflationary model in the hiddensector broken supergravity with an effectively large cutoff. The inflaton decay into righthanded neutrinos naturally causes the observed baryon asymmetry of the universe with a reheating temperature low enough to avoid the gravitino overproduction. We emphasize that all the phenomenological requirements from cosmology and particle physics are satisfied in the largecutoff theory.  [Show abstract] [Hide abstract]
ABSTRACT: We extend our models for conformal sequestering of dynamical supersymmetry breaking with decoupling vectorlike matter in several different ways. These extensions enable us to simplify concrete model building, in particular, rendering large gauge group and ad hoc global symmetry for sequestering unnecessary. Conformal sequestering appears highly natural in such circumstances.  [Show abstract] [Hide abstract]
ABSTRACT: 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 anomalymediation models. 

Article: Strongly Coupled Gauge Mediation
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ABSTRACT: A model of gauge mediation with m3/2 ≃ (1) eV is considered to motivate 100 TeV colliders. Massive mediators with standardmodel and supersymmetrybreaking gauge quantum numbers let lowscale dynamics induce sizable soft masses of the standardmodel superpartners. We circumvent potential phenomenological difficulties that such lowscale models tend to cause. 
Article: Realization of Minimal Supergravity
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ABSTRACT: Minimal supergravity mediation of supersymmetry breaking has attracted much attention due to its simplicity, which leads to its predictive power. We consider how Nature possibly realizes minimal supergravity through inflationary selection of the theory. Minimality is impressively consistent with the present observational bounds and it might be tested with the aid of lowenergy soft parameters obtained in future experiments. Comment: 18 pages, 5 figures  [Show abstract] [Hide abstract]
ABSTRACT: We extend 2D nonlinear gauge theory from the Poisson sigma model based on Lie algebroid to a model with additional twoform gauge fields. Dimensional reduction of 3D nonlinear gauge theory yields an example of such a model, which provides a realization of Courant algebroid by 2D nonlinear gauge theory. We see that the reduction of the base structure generically results in a modification of the target (algebroid) structure.
Publication Stats
1k  Citations  
184.36  Total Impact Points  
Top Journals
Institutions

20082013

Kyoto University
 Yukawa Institute for Theoretical Physics
Kioto, Kyōto, Japan


19952006

The University of Tokyo
 Department of Physics
Edo, Tōkyō, Japan
