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 $L_e - L_{\mu} - L_{\tau}$ 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, $\theta_{13}$. 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 $\bar{\nu}_e$ 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 $\bar{\nu}_e$ 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