D6 Family Symmetry and Cold Dark Matter at LHC

We consider a non-supersymmetric extension of the standard model with a family symmetry based on D6 Z2 Z2, where one of Z2's is exactly conserved. This Z2 forbids the tree-level neutrino masses and simultaneously ensures the stability of cold dark matter candidates. From the assumption that cold dark matter is fermionic we can single out the D6 singlet right-handed neutrino as the best cold dark mater candidate. We find that an inert charged Higgs with a mass between 300 and 750 GeV decays mostly into an electron (or a positron) with a large missing energy, where the missing energy is carried away by the cold dark matter candidate. This will be a clean signal at LHC.Comment: 20 pages, 7 figure

Direct and Indirect Detection of Dark Matter in D6 Flavor Symmetric Model

We study a fermionic dark matter in a non-supersymmetric extension of the standard model with a family symmetry based on D6xZ2xZ2. In our model, the final state of the dark matter annihilation is determined to be e+ e- by the flavor symmetry, which is consistent with the PAMELA result. At first, we show that our dark matter mass should be within the range of 230 GeV - 750 GeV in the WMAP analysis combined with mu to e gamma constraint. Moreover we simultaneously explain the experiments of direct and indirect detection, by simply adding a gauge and D6 singlet real scalar field. In the direct detection experiments, we show that the lighter dark matter mass ~ 230 GeV and the lighter standard model Higgs boson ~ 115 GeV is in favor of the observed bounds reported by CDMS II and XENON100. In the indirect detection experiments, we explain the positron excess reported by PAMELA through the Breit-Wigner enhancement mechanism. We also show that our model is consistent with no antiproton excess suggested by PAMELA.Comment: 20 pages, 9 figures, 2 tables, accepted version for publication in European Physical Journal

Non-Abelian Discrete Flavor Symmetries on Orbifolds

We study non-Abelian flavor symmetries on orbifolds, $S^1/Z_2$ and $T^2/Z_3$. Our extra dimensional models realize $D_N$, $\Sigma(2N^2)$, $\Delta(3N^2)$ and $\Delta(6N^2)$ including $A_4$ and $S_4$. In addition, one can also realize their subgroups such as $Q_N$, $T_7$, etc. The $S_3$ flavor symmetry can be realized on both $S^1/Z_2$ and $T^2/Z_3$ orbifolds.Comment: 16 page

Bilinear R-parity violation with flavor symmetry

Bilinear R-parity violation (BRPV) provides the simplest intrinsically supersymmetric neutrino mass generation scheme. While neutrino mixing parameters can be probed in high energy accelerators, they are unfortunately not predicted by the theory. Here we propose a model based on the discrete flavor symmetry $A_4$ with a single R-parity violating parameter, leading to (i) correct Cabbibo mixing given by the Gatto-Sartori-Tonin formula, and a successful unification-like b-tau mass relation, and (ii) a correlation between the lepton mixing angles $\theta_{13}$ and $\theta_{23}$ in agreement with recent neutrino oscillation data, as well as a (nearly) massless neutrino, leading to absence of neutrinoless double beta decay.Comment: 16 pages, 3 figures. Extended version, as published in JHE

Accidental stability of dark matter

We propose that dark matter is stable as a consequence of an accidental Z2 that results from a flavour-symmetry group which is the double-cover group of the symmetry group of one of the regular geometric solids. Although model-dependent, the phenomenology resembles that of a generic Higgs portal dark matter scheme.Comment: 12 pages, final version, published in JHE

Exploring the potential of Aeolus lidar mission for ocean color applications

The Atmospheric Laser Doppler Instrument (ALADIN) onboard the Aeolus wind mission was the first High Spectral Resolution Lidar operating in the Ultra Violet (UV) region deployed in space. This study explores and documents the feasibility of deriving ocean optical properties using data from ALADIN. A three steps (i.e. data screening, analytical estimation of the total in-water signal contribution, Look Up Table-based estimation of the in-water attenuation) retrieval algorithm was developped combining data analysis and signal simulations from a radiative transfer model. The algorithm has been implemented using the signal acquired by the Mie channel, and tested for 1-year of Aeolus observations. This approach allowed estimating the first Aeolus derived Ocean Color (OC) products in terms of the total in-water signal contribution and the in-water attenuation term in a spectral region (355 nm) not covered, during Aeolous lifetime, by operational OC products. The validation process involved comparing these products with both Biogeochemical-Argo (BGC-Argo) field measurements and satellite OC dataset distributed by ESA Ocean Color Climate Change Initiative across a set of 7 selected oceanic regions representing diverse open-ocean scenarios. These validation exercises attested the general accordance between OC reference measurements and the proposed Aeolus OC parameters. Thus, this study was able to provide statistical evidence of the sensitivity of the retrieved Aeolus in-water lidar attenuation term to the CDOM variability on a temporal/seasonal and spatial/regional basis. A preliminary estimation of the uncertainty associated to the retrieved quality controlled Klid, was performed assuming the radiometric noise as unique source of uncertainty. As a result, a median/average value of absolute relative percent difference of about 50/80% was obtained. Limits of the developed technique, possible improvements, potential adaptation to planned/future space lidar missions are discussed

The Golden Ratio Prediction for the Solar Angle from a Natural Model with A5 Flavour Symmetry

We formulate a consistent model predicting, in the leading order approximation, maximal atmospheric mixing angle, vanishing reactor angle and tan {\theta}_12 = 1/{\phi} where {\phi} is the Golden Ratio. The model is based on the flavour symmetry A5 \times Z5 \times Z3, spontaneously broken by a set of flavon fields. By minimizing the scalar potential of the theory up to the next-to-leading order in the symmetry breaking parameter, we demonstrate that this mixing pattern is naturally achieved in a finite portion of the parameter space, through the vacuum alignment of the flavon fields. The leading order approximation is stable against higher-order corrections. We also compare our construction to other models based on discrete symmetry groups.Comment: 28 pages, 2 figures. Minor changes, references added. Corrected typos in Appendix A. Version appeared on JHE

Dark Matter from Minimal Flavor Violation

We consider theories of flavored dark matter, in which the dark matter particle is part of a multiplet transforming nontrivially under the flavor group of the Standard Model in a manner consistent with the principle of Minimal Flavor Violation (MFV). MFV automatically leads to the stability of the lightest state for a large number of flavor multiplets. If neutral, this particle is an excellent dark matter candidate. Furthermore, MFV implies specific patterns of mass splittings among the flavors of dark matter and governs the structure of the couplings between dark matter and ordinary particles, leading to a rich and predictive cosmology and phenomenology. We present an illustrative phenomenological study of an effective theory of a flavor SU(3)_Q triplet, gauge singlet scalar.Comment: 10 pages, 2 figures; v2: references added, minor changes to collider analysis, conclusions unchange

Solar 8B and hep Neutrino Measurements from 1258 Days of Super-Kamiokande Data

Solar neutrino measurements from 1258 days of data from the Super-Kamiokande detector are presented. The measurements are based on recoil electrons in the energy range 5.0-20.0MeV. The measured solar neutrino flux is 2.32 +- 0.03(stat.) +0.08-0.07(sys.)*10^6cm^{-2}s^{-1}, which is 45.1+-0.5(stat.)+1.6-1.4(sys.)% of that predicted by the BP2000 SSM. The day vs night flux asymmetry is 0.033+-0.022(stat.)+0.013-0.012(sys.). The recoil electron energy spectrum is consistent with no spectral distortion (\chi^2/d.o.f. = 19.0/18). The seasonal variation of the flux is consistent with that expected from the eccentricity of the Earth's orbit (\chi^2/d.o.f. = 3.7/7). For the hep neutrino flux, we set a 90% C.L. upper limit of 40 *10^3cm^{-2}s^{-1}, which is 4.3 times the BP2000 SSM prediction.Comment: 7 pages, 5 figures, submitted to PRL (part of this paper

Experimental Analysis of Sources of Error in Evolutionary Studies Based on Roche/454 Pyrosequencing of Viral Genomes

Factors affecting the reliability of Roche/454 pyrosequencing for analyzing sequence polymorphism in within-host viral populations were assessed by two experiments: 1) sequencing four clonal simian immunodeficiency virus (SIV) stocks and 2) sequencing mixtures in different proportions of two SIV strains with known fixed nucleotide differences. Observed nucleotide diversity and frequency of undetermined nucleotides were increased at sites in homopolymer runs of four or more identical nucleotides, particularly at AT sites. However, in the mixed-strain experiments, the effects on estimated nucleotide diversity of such errors were small in comparison to known strain differences. The results suggest that biologically meaningful variants present at a frequency of around 10% and possibly much lower are easily distinguished from artifacts of the sequencing process. Analysis of the clonal stocks revealed numerous rare variants that showed the signature of purifying selection and that elimination of variants at frequencies of less than 1% reduced estimates of nucleotide diversity by about an order of magnitude. Thus, using a 1% frequency cutoff for accepting a variant as real represents a conservative standard, which may be useful in studies that are focused on the discovery of specific mutations (such as those conferring immune escape or drug resistance). On the other hand, if the goal is to estimate nucleotide diversity, an optimal strategy might be to include all observed variants (even those at less than 1% frequency), while masking out homopolymer runs of four or more nucleotides