Renormalization Group Running of Lepton Mixing Parameters in See-Saw Models with S4S_4 Flavor Symmetry

We study the renormalization group running of the tri-bimaximal mixing predicted by the two typical $S_4$ flavor models at leading order. Although the textures of the mass matrices are completely different, the evolution of neutrino mass and mixing parameters is found to display approximately the same pattern. For both normal hierarchy and inverted hierarchy spectrum, the quantum corrections to both atmospheric and reactor neutrino mixing angles are so small that they can be neglected. The evolution of the solar mixing angle $\theta_{12}$ depends on $\tan\beta$ and neutrino mass spectrum, the deviation from its tri-bimaximal value could be large. Taking into account the renormalization group running effect, the neutrino spectrum is constrained by experimental data on $\theta_{12}$ in addition to the self-consistency conditions of the models, and the inverted hierarchy spectrum is disfavored for large $\tan\beta$. The evolution of light-neutrino masses is approximately described by a common scaling factor.Comment: 23 pages, 6figure

Experimental Requirements to Determine the Neutrino Mass Hierarchy Using Reactor Neutrinos

This paper presents experimental requirements to determine the neutrino mass hierarchy using reactor neutrinos. The detector shall be located at a baseline around 58 km from the reactor(s) to measure the energy spectrum of electron antineutrinos ($\bar{\nu}_e$) precisely. By applying Fourier cosine and sine transform to the L/E spectrum, features of the neutrino mass hierarchy can be extracted from the $|\Delta{m}^2_{31}|$ and $|\Delta{m}^2_{32}|$ oscillations. To determine the neutrino mass hierarchy above 90% probability, requirements to the baseline, the energy resolution, the energy scale uncertainty, the detector mass and the event statistics are studied at different values of $\sin^2(2\theta_{13})$Comment: Update Fig.

Experimental Conditions for Determination of the Neutrino Mass Hierarchy with Reactor Antineutrinos

This article reports the optimized experimental requirements to determine neutrino mass hierarchy using electron antineutrinos ($\bar{\nu}_e$) generated in a nuclear reactor. The features of the neutrino mass hierarchy can be extracted from the $|\Delta m^{2}_{31}|$ and $|\Delta m^{2}_{32}|$ oscillations by applying the Fourier sine and cosine transform to the $L/E$ spectrum. To determine the neutrino mass hierarchy above 90\% probability, the requirements on the energy resolution as a function of the baseline are studied at $\sin 2\theta_{13}=0.1$. If the energy resolution of the neutrino detector is less than $0.04/ \sqrt{E_{\nu}}$ and the determination probability obtained from Bayes' theorem is above 90\%, the detector needs to be located around 48--53 km from the reactor(s) to measure the energy spectrum of $\bar{\nu}_e$. These results will be helpful for setting up an experiment to determine the neutrino mass hierarchy, which is an important problem in neutrino physics

A universe in a global monopole

We investigate brane physics in a universe with an extra dimensional global monopole and negative bulk cosmological constant. The graviton zero mode is naturally divergent; we thus invoke a physical cut-off to induce four dimensional gravity on a brane at the monopole core. Independently, the massive Kaluza-Klein modes have naturally compactified extra dimensions, inducing a discrete spectrum. This spectrum remains consistent with four dimensional gravity on the brane, even for small mass gap. Extra dimensional matter fields also induce four dimensional matter fields on the brane, with the same Kaluza-Klein spectrum of excited states. We choose parameters to solve the hierarchy problem; that is, to induce the observed hierarchy between particle and Planck scales in the effective four dimensional universe.Comment: 22 pages, 2 eps figures, revte

Neutrino Mass Hierarchy Determination Using Reactor Antineutrinos

Building on earlier studies, we investigate the possibility to determine the type of neutrino mass spectrum (i.e., "the neutrino mass hierarchy") in a high statistics reactor electron antineutrino experiment with a relatively large KamLAND-like detector and an optimal baseline of 60 Km. We analyze systematically the Fourier Sine and Cosine Transforms (FST and FCT) of simulated reactor antineutrino data with reference to their specific mass hierarchy-dependent features discussed earlier in the literature. We perform also a binned \chi^2 analysis of the sensitivity of simulated reactor electron antineutrino event spectrum data to the neutrino mass hierarchy, and determine, in particular, the characteristics of the detector and the experiment (energy resolution, visible energy threshold, exposure, systematic errors, binning of data, etc.), which would allow us to get significant information on, or even determine, the type of the neutrino mass spectrum. We find that if \sin^2 2\theta_{13} is sufficiently large, \sin^2 2\theta_{13} \gtap 0.02, the requirements on the set-up of interest are very challenging, but not impossible to realize.Comment: 32 pages, 27 figures, accepted in Journal of High Energy Physic

Horizontal, Anomalous U(1) Symmetry for the More Minimal Supersymmetric Standard Model

We construct explicit examples with a horizontal, ``anomalous'' $U(1)$ gauge group, which, in a supersymmetric extension of the standard model, reproduce qualitative features of the fermion spectrum and CKM matrix, and suppress FCNC and proton decay rates without the imposition of global symmetries. We review the motivation for such ``more'' minimal supersymmetric standard models and their predictions for the sparticle spectrum. There is a mass hierarchy in the scalar sector which is the inverse of the fermion mass hierarchy. We show in detail why DeltaS = 2 FCNC are suppressed when compared with naive estimates for nondegenerate squarks.Comment: Revised version clarifies calculation of FCNC amplitudes and rules out one model considered previousl

Soft-Wall Stabilization

We propose a general class of five-dimensional soft-wall models with AdS metric near the ultraviolet brane and four-dimensional Poincar\'e invariance, where the infrared scale is determined dynamically. A large UV/IR hierarchy can be generated without any fine-tuning, thus solving the electroweak/Planck scale hierarchy problem. Generically, the spectrum of fluctuations is discrete with a level spacing (mass gap) provided by the inverse length of the wall, similar to RS1 models with Standard Model fields propagating in the bulk. Moreover two particularly interesting cases arise. They can describe: (a) a theory with a continuous spectrum above the mass gap which can model unparticles corresponding to operators of a CFT where the conformal symmetry is broken by a mass gap, and; (b) a theory with a discrete spectrum provided by linear Regge trajectories as in AdS/QCD models.Comment: 27 pages, 6 figures, 1 table. v2: references added, version to appear in NJP Focus Issue on Extra Dimension

Determining the Neutrino Mass Hierarchy with Atmospheric Neutrinos

The possibility to determine the type of neutrino mass hierarchy by studying atmospheric neutrino oscillations with a detector capable to distinguish between neutrino and antineutrino events, such as magnetized iron calorimeters, is considered. We discuss how the ability to distinguish between the neutrino mass spectrum with normal and inverted hierarchy depends on detector characteristics like neutrino energy and direction resolutions or charge miss-identification, and on the systematical uncertainties related to the atmospheric neutrino fluxes. We show also how the neutrino mass hierarchy determination depends on the true values of $\theta_{13}$ and $\theta_{23}$, as well as on the type of the true hierarchy. We find that for $\mu$-like events, an accurate reconstruction of the energy and direction of the neutrino greatly improves the sensitivity to the type of neutrino mass spectrum. For $\sin^22\theta_{13} \cong 0.1$ and a precision of 5% in the reconstruction of the neutrino energy and $5^\circ$ in the neutrino direction, the type of neutrino mass hierarchy can be identified at the 2$\sigma$ C.L. with approximately 200 events. For resolutions of 15% for the neutrino energy and $15^\circ$ for the neutrino direction roughly one order of magnitude larger event numbers are required. For a detector capable to distinguish between $\nu_e$ and $\bar\nu_e$ induced events the requirements on energy and direction resolutions are, in general, less demanding than for a detector with muon charge identification.Comment: 24 pages, 8 figure