If the inflaton is a pseudo-scalar axion, the axion shift symmetry can protect the flatness of its potential from too large radiative corrections. This possibility, known as natural inflation,â€¦ (More)

The connection of Dark Matter (DM) to our particle physics model is still one of the open cosmological questions. In these proceedings I will argue that axinos can be successful Cold Dark Matterâ€¦ (More)

Supersymmetric extensions of the Standard Model which incorporate the axion solution to the strong CP problem necessarily contain also the axino, the fermionic partner of the axion. In contrast toâ€¦ (More)

We present a new mechanism for baryogenesis by introducing a heavy vector-like SU(2)W singlet quark(s) with Qem = 2 3 quark U or Qem = âˆ’13 quark D. The lifetime of the heavy quark is assumed to be inâ€¦ (More)

It is generally believed that the cosmological constant problem is the most severe hierarchy problem in particle physics. The hierarchy problem has been formulated since 1975 in connection with grandâ€¦ (More)

A Z3 orbifold compactification of E8Ã—Eâ€² 8 heterotic string is considered toward a trinification SU(3)3 with three light families. The GUT scale VEVâ€™s of the SU(2)W Ã—U(1)Y Ã— SU(3)c singlet chiralâ€¦ (More)

The model independent axion of string theory has a decay constant of order of the Planck scale. We explore the properties of this quintessence candidate (quintaxion) in the scheme of hidden sectorâ€¦ (More)

We show that the hierarchically small Î¼ term in supersymmetric theories is a consequence of two identical pairs of Higgs doublets taking a democratic form for their mass matrix. We briefly discussâ€¦ (More)

I review the history on neutrino magnetic moments and apply the neurino magnetic moment idea to constrain its bound from Super-Kamiokande neutrino oscillation data.

We construct a supersymmetric standard model in the context of the Z12âˆ’I orbifold compactification of the heterotic string theory. The gauge group is SU(3)c Ã— SU(2)L Ã—U(1)Y Ã—U(1)4 Ã— [SO(10) Ã—U(1)3]â€².â€¦ (More)