[Show abstract][Hide abstract] 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 slow-roll
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
0.950--0.965, which includes the central value from observational data.
Preview · Article · May 2013 · Progress of Theoretical and Experimental Physics
[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 Nambu-Goldstone
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
tree-level 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 pseudo-goldstino 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.
Preview · Article · Jan 2011 · Journal of High Energy Physics
[Show abstract][Hide abstract] 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 Fayet-Iliopoulos-like term in broken supergravity.
Preview · Article · Aug 2010 · Progress of Theoretical Physics
[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
Preview · Article · Mar 2010 · Physical review D: Particles and fields
[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.
Preview · Article · Oct 2009 · Physical review D: Particles and fields
[Show abstract][Hide abstract] ABSTRACT: Strongly coupled semi-direct 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)  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, low-energy dynamics with gauge mediation between a hidden sector of SUSY breaking and the visible sector of SUSY standard
Preview · Article · Aug 2009 · Physical review D: Particles and fields
[Show abstract][Hide abstract] ABSTRACT: We study gaugino mass generation in the context of semi-direct 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 non-vanishing leading contribution to the gaugino mass.
[Show abstract][Hide abstract] ABSTRACT: 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 , 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 supersymmetry-breaking 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 long-lived in hand, we are led to suspect that our SUSY-breaking 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 slow-roll 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 supersymmetry-breaking 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 right-handed Slow-roll inflation  takes place when the potential is flat enough, which is realized through tuning the form of potential by symmetry or by hand. 1 In non-supersymmetric or supersymmetry-broken 2 cases, the required tuning is rather straightforward to flatten a potential with the kinetic term intact. On the other hand, in the supersymmetry-invariant
[Show abstract][Hide abstract] ABSTRACT: We examine the amount of parameter tuning to make slow-roll inflation marginally eternal by considering an R-invariant chaotic inflation as an example of one-parameter 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 hidden-sector broken supergravity with an effectively large cutoff. The inflaton decay into right-handed 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 large-cutoff 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.
Preview · Article · Feb 2006 · Physical review D: Particles and fields
[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 anomaly-mediation models.
Preview · Article · Jan 2006 · Physical review D: Particles and fields
[Show abstract][Hide abstract] ABSTRACT: A model of gauge mediation with m3/2 ≃ (1) eV is considered to motivate 100 TeV colliders. Massive mediators with standard-model and supersymmetry-breaking gauge
quantum numbers let low-scale dynamics induce sizable soft masses of the standard-model superpartners. We circumvent potential
phenomenological difficulties that such low-scale models tend to cause.
Preview · Article · Jan 2005 · Progress of Theoretical Physics
[Show abstract][Hide abstract] 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 low-energy 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 two-form
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.
Preview · Article · Aug 2004 · Journal of High Energy Physics