R-Parity Violation and Non-Abelian Discrete Family Symmetry

We investigate the implications of R-parity violating operators in a model with family symmetry. The family symmetry can determine the form of R-parity violating operators as well as the Yukawa matrices responsible for fermion masses and mixings. In this paper we consider a concrete model with non-abelian discrete symmetry Q_6 which contains only three R-parity violating operators. We find that ratios of decay rates of the lepton flavor violating processes are fixed thanks to the family symmetry, predicting BR(tau to 3e)/BR(tau to 3mu) ~ 4 m_{mu}^2/m_{tau}^2.Comment: 20 pages, 3 figure

In-water lidar simulations: the ALADIN ADM-Aeolus backscattered signal at 355 nm

The Lidar Ocean Color (LiOC) Monte Carlo code has been developed to simulate the in-water propagation of the lidar beam emitted by the ALADIN ADM-Aeolus instrument in the ultraviolet (UV) spectral region (∼ 355 nm). To this end, LiOC accounts for reflection/transmission processes at the sea surface, absorption and multiple scattering in the water volume, and reflection from the sea bottom. The water volume components included in the model are pure seawater, Chlorophyll-a concentration (Chl-a), Colored Dissolved Organic Matter (CDOM), and/or a generic absorbing species. By considering the transmission/reception measurement geometry of ALADIN ADM-Aeolus, the study documents the variability of the normalized backscattered signal in different bio-optical conditions. The potential for data product retrieval based on information at 355 nm is considered by developing a demonstrative lookup table to estimate the absorption budget exceeding that explained by Chl-a. Results acknowledge the interest of space programs in exploiting UV bands for ocean color remote sensing, as, for instance, addressed by the PACE mission of NASA

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

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

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

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

Repressing Anarchy in Neutrino Mass Textures

The recent results that $\theta_{13}$ is relatively large, of the order of the previous upper bound, and the indications of a sizable deviation of $\theta_{23}$ from the maximal value are in agreement with the predictions of Anarchy in the lepton sector. The quark and charged lepton hierarchies can then be reproduced in a SU(5) GUT context by attributing non-vanishing $U(1)_{FN}$ charges, different for each family, only to the SU(5) tenplet states. The fact that the observed mass hierarchies are stronger for up quarks than for down quarks and charged leptons supports this idea. As discussed in the past, in the flexible context of $SU(5)\otimes U(1)_{FN}$, different patterns of charges can be adopted going from Anarchy to various types of hierarchy. We revisit this approach by also considering new models and we compare all versions to the present data. As a result we confirm that, by relaxing the extreme ansatz of equal $U(1)_{FN}$ charges for all SU(5) pentaplets and singlets, better agreement with the data than for Anarchy is obtained without increasing the model complexity. We also present the distributions obtained in the different models for the Dirac CP-violating phase. Finally we discuss the relative merits of these simple models.Comment: v1: 12 pages, 3 figures; v2: 13 pages, 3 figures, text improved, matches version accepted for publication; v3: submitted to add an acknowledgment to a networ

Video Capsule Retention in a Zenker Diverticulum

We report the case of a video capsule endoscope lodged within a Zenker diverticulum. The system that was equipped with a real-time viewer showed an unchanging image unlike esophageal or gastric mucosa, suggesting that the capsule was elsewhere. The presence of cervical discomfort suggested video capsule retention in a Zenker diverticulum. The capsule was removed endoscopically and reinserted using a hood-assisted endoscope and the procedure was completed