Renormalizable minimal SO(10) GUT in 4D and 5D

This report is a review of the present status of GUT, especially renormalizable minimal SO(10) GUT, and its future prospect. It consists of two parts. In part I, I review how the minimal renormalizable supersymmetric SO(10) GUT, an SO(10) framework with only one ${\bf 10}$ and one $\bar{\bf 126}$ Higgs multiplets in the Yukawa sector, is attractive because of its high predictivity. Indeed it not only gave a consistent predictions on neutrino oscillation data but also did reasonable and interesting values for Leptogenesis, LFV, muon g-2, neutrinoless double beta decay etc. However, this model suffers from problems, apart from the small deviations from the observed values, related to running of gauge couplings and proton decay. The gauge coupling unification may be spoiled due to the presence of intermediate scales much lighter than the grand unification (GUT) scale. In addition, the gauge couplings blow up around the GUT scale because of the presence of Higgs multiplets of large representations. In order to remedy these pathologies, in part II, we extend GUT into 5D. We propose two approaches: one is to consider the warped extra dimension, using the bulk Higgs profile to explain the intermediate energy scales. Another is to use the orbifold GUT. Both approaches are complementary to each other.Comment: A talk in the workshop on GUT held at Ritsumeikan Univ. on Dec.17-19 200

Renormalization Group Equation of Quark-Lepton Mass Matrices in the SO(10) Model with Two Higgs Scalars

The renormalization group equations (RGEs) of the mass matrices of quarks and leptons in a SO(10) model with two Higgs scalars in the Yukawa coupling are studied. This model is the minimal model of SUSY and non-SUSY SO(10) GUT which can reproduce all the experimental data. Non-SUSY SO(10) GUT model has the intermediate energy phase, Pati-Salam phase, and passes through the symmetry breaking pattern, $SO(10) \to SU(2)_L \times SU(2)_R \times SU(4)_C \to SU(2)_L \times U(1)_Y \times SU(3)_C$. Though minimal, it has, after the Pati-Salam phase, four Higgs doublets in Yukawa interactions. We consider the RGE's of the Yukawa coupling constants of quarks and charged leptons and of the coupling constants of the dimension five operators of neutrinos corresponding to the above symmetry breaking pattern. The scalar quartic interactions are also incorporated.Comment: 16 pages, 1 figure; A discussion of scalar self couplings contributions to the RGE of neutrino mass matrix and some references added, a figure replace

Universality of Quark-Lepton Mass Matrix

The recently observed lepton mixing angle $\theta_{13}$ of the MNS mixing matrix is well incorporated in a universal mixing hypothesis between quark and lepton sectors. This hypothesis asserts that, in the charged lepton diagonal base, all other mass matrices for up- and down-type quarks and light neutrinos are diagonalized by the same unitary matrix except for the phase elements. It is expressed as $V_{CKM}= U_{MNS}(\delta^\prime)^\dagger P U_{MNS}(\delta)$ for quark mixing matrix $V_{CKM}$ and lepton mixing matrix $U_{MNS}(\delta)$ in the phenomenological level. Here $P$ is a diagonal phase mass matrix. $\delta^\prime$ is a slightly different phase parameter from the Dirac CP violating phase $\delta=1.1\pi$ (best fit) in the MNS lepton mixing matrix.Comment: 6 pages, 2 figures, accepted by MPL