A Solution to the Polonyi Problem in the Minimum SUSY-GUT

We show that the Polonyi problem is solved in the minimum SUSY-GUT model in which a self-coupling strength for a heavy Higgs $\Sigma$, $\lambda\Sigma^{3}$, is very small $\lambda\sim 10^{-6}$. It is stressed that with this small $\lambda$ the mass of the physical $\Sigma$ becomes m_{\Sigma} \sim 10^{12}\GEV and the unification scale is raised up to the gravitational one, M\simeq 2\times 10^{18}\GEV. A potential problem, however, is also pointed out in this GUT model

Large Lepton Mixing in a Coset-space Family Unification on E7/SU(5)×U(1)3E_7/SU(5) \times U(1)^3

We study a coset-space unification model for families based on $E_7/SU(5) \times U(1)^3$. We find that qualitative structure of quark and lepton mass matrices in this model describes very well the observation. We stress, in particular, that the large mixing angle, $\sin^22\theta_{\nu_\mu\nu_\tau} \simeq 1$, required for the atmospheric neutrino oscillation reported by the SuperKamiokande collaboration, is naturally obtained, which is a consequence of unparallel family structure in the present coset-space unification.Comment: 8 pages, Latex2

Quark Lepton Mass Hierarchies and the Baryon Asymmetry

The mass hierarchies of quarks and charged leptons as well as a large \n_\m-\n_\t mixing angle are naturally explained by the Frogatt-Nielsen mechanism with a nonparallel family structure of chiral charges. We extend this mechanism to right-handed neutrinos. Their out-of-equilibrium decay generates a cosmological baryon asymmetry whose size is quantized in powers of the hierarchy parameter \e^2. For the simplest hierarchy pattern the neutrino mass \bar{m}_\n= (m_{\n_\m}m_{\n_\t})^{1/2} \sim 10^{-2} eV, which is inferred from present indications for neutrino oscillations, implies a baryon asymmetry $n_B/s \sim 10^{-10}$. The corresponding baryogenesis temperature is $T_B \sim 10^{10}$ GeV.Comment: 7 page

An N=2 SUSY Gauge Model for Dynamical Breaking of the Grand Unified SU(5) Symmetry

We construct an extension of the recently proposed dynamical model for the breaking of SU(5)$_{\rm GUT}$ gauge symmetry, in which a pair of massless chiral supermultiplets for Higgs doublets are naturally obtained. We point out that a model at a specific point in the parameter space of superpotential is regarded as a low-energy effective theory of an N=2 supersymmetric gauge model for the strongly interacting hypercolor sector.Comment: 7 page

Mass Generation for an Ultralight Axion

If a global chiral symmetry is explicitly broken by anomalies in nonabelian gauge theories, a pseudo Nambu-Goldstone boson (axion) associated with a spontaneous breakdown of such a global symmetry acquires a mass through nonperturbative instanton effects. We calculate the axion mass assuming a supersymmetric SU(2) gauge theory and show that the axion obtains an extremely small mass when the SU(2) gauge symmetry is broken down at very high energy, say at the Planck scale. We identify the axion with a hypothetical ultralight boson field proposed to account for a small but nonzero cosmological constant suggested from recent cosmological observations.Comment: 11 pages, Late

Dynamical Supersymmetry Breaking in Vector-like Gauge Theories

We provide vector-like gauge theories which break supersymmetry dynamically.Comment: 3 pages, phyzzx, to appear in Prog. Theor. Phy

A Conformal Gauge Mediation and Dark Matter with Only One Parameter

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 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 10^2 TeV. Then, the sfermion and gaugino masses are fixed to be of order 10^2~10^3 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.Comment: 17 page