16,216 research outputs found
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 and one
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
The current problems of the minimal SO(10) GUT and their solutions
This talk consists of two parts. In part I we review how the minimal
renormalizable supersymmetric SO(10) model, an SO(10) framework with only one
10 and one 126 Higgs multiplets in the Yukawa sector, is attractive because of
its highly predictive power. Indeed it not only gives a consistent predictions
on neutrino oscillation data but also gives reasonable and interesting values
for leptogenesis, LFV, muon g-2, neutrinoless double beta decay etc. However,
this model suffers from problems related to running of gauge couplings. The
gauge coupling unification may be spoiled due to the presence of Higgs
multiplets 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 part II we consider the minimal
SO(10) model in the warped extra dimension and show a possibility to solve
these problems.Comment: 15 pages, 7 figures, Talk given at the International Workshop on
Neutrino Masses and Mixings Toward Unified Understanding of Quarks and Lepton
Mass Matrices, held at University of Shizuoka on December 17-19, 200
Massive Analogue of Ashtekar-CJD Action
The action of Ashtekar gravity have been found by Cappovilla, Jacobson and
Dell. It does not depend on the metric nor the signature of the space-time. The
action has a similar structure as that of a massless relativistic particle. The
former is naturally generalized by adding a term analogous to a mass term of
the relativistic particle. The new action possesses a constant parameter
regarded as a kind of a cosmological constant. It is interesting to find a
covariant Einstein equation from the action. In order to do it we will examine
how the geometrical quantities are determined from the non-metric action and
how the Einstein equation follows from it.Comment: 6p. Te
Strongly Correlated Electrons and Neutron Scattering
Various aspects of close and interesting relationship between
antiferromagnetism and singlet ground states are introduced for which neutron
scattering have been playing vital roles. The special emphasis is on the
disorder-induced antiferromagnetism in spin-Peierls systems, which can be
viewed as a nucleation process of classical magnetic order in the background of
singlet state whose origin is purely quantum-mechanical. It is then pointed out
that similar features will be found in Ce_xCu_2Si_2 and high T_c cuprates.
Finally the possible charge ordering process in NaV_2O_5 is discussed which
leads to the quenching of localized spins.Comment: 8 pages, 3 figures, Proceedings of 7th ISSP International Symposium
"Frontiers in Neutron Scattering Research" (To appear in J. Phys. Chem.
Solids (1999)
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