160 research outputs found
Neutrino Oscillation Scenarios and GUT Model Predictions
The present experimental situation regarding neutrino oscillations is first
summarized, followed by an overview of selected grand unified models which have
been proposed to explain the various scenarios with three active neutrinos and
their right-handed counterparts. Special attention is given to the general
features of the models and their ability to favor some scenarios over others.Comment: 11 pages, talk given at the Joint U.S./Japan Workshop on New
Initiatives in Lepton Flavor Violation and Neutrino Oscillations with Very
Intense Muon and Neutrino Sources (Honolulu), October 2-6, 200
SO(10) GUT Models and Their Present Success in Explaining Mass and Mixing Data
Some features of SO(10) GUT models are reviewed, and a number of such models
in the literature are compared. While some have been eliminated by recent
neutrino data, others are presently successful in explaining the quark and
lepton mass and mixing data. A short description of one very predictive model
is given which illustrates some of the features discussed. Future tests of the
models are pointed out including one which contrasts sharply with those models
based on an type symmetry.Comment: 9 pages, paper presented at the Neutrinos and Implications for
Physics Beyond the Standard Model Conference, SUNY at Stony Brook, October
11-13, 200
Bimaximal Mixing in an SO(10) Minimal Higgs Model
An SO(10) SUSY GUT model was previously presented based on a minimal set of
Higgs fields. The quark and lepton mass matrices derived fitted the data
extremely well and led to large mixing of muon- and tau-neutrinos in agreement
with the atmospheric neutrino data and to the small-angle MSW solution for the
solar neutrinos. Here we show how a slight modification leading to a non-zero
up quark mass can result in bimaximal mixing for the atmospheric and solar
neutrinos. The "just-so" vacuum solution is slightly favored over the
large-angle MSW solution on the basis of the hierarchy required for the
right-handed Majorana matrix and the more nearly-maximal mixing angles
obtained.Comment: 10 pages, LaTeX, several references adde
Comparison of LMA and LOW Solar Solution Predictions in an SO(10) GUT Model
Within the framework of an SO(10) GUT model that can accommodate both the LMA
and LOW solar neutrino mixing solutions by appropriate choice of the
right-handed Majorana matrix elements, we present explicit predictions for the
neutrino oscillation parameters \Delta m^2_{21}, \sin^2 2\theta_{12}, \sin^2
2\theta_{23}, \sin^2 2\theta_{13}, and \delta_{CP}. Given the observed near
maximality of the atmospheric mixing, the model favors the LMA solution and
predicts that \delta_{CP} is small. The suitability of Neutrino Superbeams and
Neutrino Factories for precision tests of the two model versions is discussed.Comment: Title, abstract and emphasis changed, references adde
Model Predictions for Neutrino Oscillation Parameters
We have surveyed leptonic and grand unified models of neutrino masses and
mixings in the literature which are still viable and give numerical predictions
for the reactor angle, . The results are of considerable interest
in anticipation of the next generation reactor experiments and the possible
future need for neutrino factories. Of the 63 models considered which were
published or posted on the Archive before June 2006, half predict values of
\sin^2 2\theta_{13} \gsim 0.015, which should yield positive signals for
disappearance in the reactor experiments planned for the near
future. Depending upon the outcome of those experiments, half of the models can
be eliminated on the basis of the presence or absence of such an observed
disappearance signal.Comment: 23 pages including 3 figures; published versio
Explicit SO(10) Supersymmetric Grand Unified Model
A complete set of Higgs and matter superfields is introduced with
well-defined SO(10) properties and U(1) \times Z_2 \times Z_2 family charges
from which the Higgs and Yukawa superpotentials are constructed. The Higgs
fields solve the doublet-triplet splitting problem, while the structures of the
four Dirac fermion mass matrices obtained involve just six effective Yukawa
operators. The right-handed Majorana matrix, M_R, arises from one Higgs field
coupling to several pairs of superheavy conjugate neutrino singlets. In terms
of 10 input parameters to the mass matrices, the model accurately yields the 20
masses and mixings of the lightest quarks and leptons, as well as the masses of
the 3 heavy right-handed neutrinos. The bimaximal atmospheric and solar
neutrino vacuum solutions are favored in this simplest version with a moderate
hierarchy in M_R. The large mixing angle MSW solution is obtainable, on the
other hand, with a considerably larger hierarchy in M_R which is also necessary
to obtain baryogenesis through the leptogenesis mechanism.Comment: 11 pages including 4 figures, contribution to NEUTRINO 2000 and talk
presented at SUSY2
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