On Neutrinos and Fermionic Mass Patterns

Recent data on neutrino mass differences are consistent with a hierarchical neutrino mass structure strikingly similar to what is observed for the other fermionic masses.Comment: 8pages, 2figure

No anomalous supersaturation in ultracold cirrus laboratory experiments

High-altitude cirrus clouds are climatically important: their formation freeze-dries air ascending to the stratosphere to its final value, and their radiative impact is disproportionately large. However, their formation and growth are not fully understood, and multiple in situ aircraft campaigns have observed frequent and persistent apparent water vapor supersaturations of 5 %–25 % in ultracold cirrus (T<205 K), even in the presence of ice particles. A variety of explanations for these observations have been put forth, including that ultracold cirrus are dominated by metastable ice whose vapor pressure exceeds that of hexagonal ice. The 2013 IsoCloud campaign at the Aerosol Interaction and Dynamics in the Atmosphere (AIDA) cloud and aerosol chamber allowed explicit testing of cirrus formation dynamics at these low temperatures. A series of 28 experiments allows robust estimation of the saturation vapor pressure over ice for temperatures between 189 and 235 K, with a variety of ice nucleating particles. Experiments are rapid enough (∼10 min) to allow detection of any metastable ice that may form, as the timescale for annealing to hexagonal ice is hours or longer over the whole experimental temperature range. We show that in all experiments, saturation vapor pressures are fully consistent with expected values for hexagonal ice and inconsistent with the highest values postulated for metastable ice, with no temperature-dependent deviations from expected saturation vapor pressure. If metastable ice forms in ultracold cirrus clouds, it appears to have a vapor pressure indistinguishable from that of hexagonal ice to within about 4.5 %

Direct versus indirect detection in mSUGRA with self-consistent halo models

We perform a detailed analysis of the detection prospects of neutralino dark matter in the mSUGRA framework. We focus on models with a thermal relic density, estimated with high accuracy using the DarkSUSY package, in the range favored by current precision cosmological measurements. Direct and indirect detection rates are computed implementing two models for the dark matter halo, tracing opposite regimes for the phase of baryon infall, with fully consistent density profiles and velocity distribution functions. This has allowed, for the first time, a fully consistent comparison between direct and indirect detection prospects. We discuss all relevant regimes in the mSUGRA parameter space, underlining relevant effects, and providing the basis for extending the discussion to alternative frameworks. In general, we find that direct detection and searches for antideuterons in the cosmic rays seems to be the most promising ways to search for neutralinos in these scenarios.Comment: 26 pages, 9 figure

The Role of Antimatter Searches in the Hunt for Supersymmetric Dark Matter

We analyze the antimatter yield of supersymmetric (SUSY) models with large neutralino annihilation cross sections. We introduce three benchmark scenarios, respectively featuring bino, wino and higgsino-like lightest neutralinos, and we study in detail the resulting antimatter spectral features. We carry out a systematic and transparent comparison between current and future prospects for direct detection, neutrino telescopes and antimatter searches. We demonstrate that often, in the models we consider, antimatter searches are the only detection channel which already constrains the SUSY parameter space. Particularly large antiprotons fluxes are expected for wino-like lightest neutralinos, while significant antideuteron fluxes result from resonantly annihilating binos. We introduce a simple and general recipe which allows to assess the visibility of a given SUSY model at future antimatter search facilities. We provide evidence that upcoming space-based experiments, like PAMELA or AMS, are going to be, in many cases, the unique open road towards dark matter discovery.Comment: 34 pages, 18 figures; V2: misprints in the labels of fig. 2,3 and 5 correcte

Biochemical parameters of silver catfish (Rhamdia quelen) after transport with eugenol or essential oil of Lippia alba added to the water

The transport of live fish is a routine practice in aquaculture and constitutes a considerable source of stress to the animals. The addition of anesthetic to the water used for fish transport can prevent or mitigate the deleterious effects of transport stress. This study investigated the effects of the addition of eugenol (EUG) (1.5 or 3.0 mu L L-1) and essential oil of Lippia alba (EOL) (10 or 20 mu L L-1) on metabolic parameters (glycogen, lactate and total protein levels) in liver and muscle, acetylcholinesterase activity (AChE) in muscle and brain, and the levels of protein carbonyl (PC), thiobarbituric acid reactive substances (TBARS) and nonprotein thiol groups (NPSH) and activity of glutathione-S-transferase in the liver of silver catfish (Rhamdia quelen; Quoy and Gaimard, 1824) transported for four hours in plastic bags (loading density of 169.2 g L-1). The addition of various concentrations of EUG (1.5 or 3.0 mu L L-1) and EOL (10 or 20 mu L L-1) to the transport water is advisable for the transportation of silver catfish, since both concentrations of these substances increased the levels of NPSH antioxidant and decreased the TBARS levels in the liver. In addition, the lower liver levels of glycogen and lactate in these groups and lower AChE activity in the brain (EOL 10 or 20 mu L L-1) compared to the control group indicate that the energetic metabolism and neurotransmission were lower after administration of anesthetics, contributing to the maintenance of homeostasis and sedation status.Fundacao de Amparo a Pesquisa do Estado do Rio Grande do Sul (FAPERGS/PRONEX) [10/0016-8]; Conselho Nacional de Pesquisa e Desenvolvimento Cientifico (CNPq) [470964/2009-0]; Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES); CNPqinfo:eu-repo/semantics/publishedVersio

Neutrinoless double-beta decay and seesaw mechanism

From the standard seesaw mechanism of neutrino mass generation, which is based on the assumption that the lepton number is violated at a large (~10exp(+15) GeV) scale, follows that the neutrinoless double-beta decay is ruled by the Majorana neutrino mass mechanism. Within this notion, for the inverted neutrino-mass hierarchy we derive allowed ranges of half-lives of the neutrinoless double-beta decay for nuclei of experimental interest with different sets of nuclear matrix elements. The present-day results of the calculation of the neutrinoless double-beta decay nuclear matrix elements are briefly discussed. We argue that if neutrinoless double-beta decay will be observed in future experiments sensitive to the effective Majorana mass in the inverted mass hierarchy region, a comparison of the derived ranges with measured half-lives will allow us to probe the standard seesaw mechanism assuming that future cosmological data will establish the sum of neutrino masses to be about 0.2 eV.Comment: Some changes in sections I, II, IV, and V; two new figures; additional reference

Observation of the Shadowing of Cosmic Rays by the Moon using a Deep Underground Detector

Using data collected by the MACRO experiment during the years 1989-1996, we show evidence for the shadow of the moon in the underground cosmic ray flux with a significance of 3.6 sigma. This detection of the shadowing effect is the first by an underground detector. A maximum-likelihood analysis is used to determine that the angular resolution of the apparatus is 0.9+/-0.3 degrees. These results demonstrate MACRO's capabilities as a muon telescope by confirming its absolute pointing ability and quantifying its angular resolution.Comment: 14 pages, 8 figures Submitted to Phys. Rev.

Search for massive rare particles with MACRO

Massive rare particles have been searched for in the penetrating cosmic radiation using the MACRO apparatus at the Gran Sasso National Laboratories. Liquid scintillators, streamer tubes and nuclear track detectors have been used to search for magnetic monopoles (MMs). Based on no observation of such signals, stringent flux limits are established for MMs as slow as a few 10^(-5)c. The methods based on the scintillator and on the nuclear track subdetectors were also applied to search for nuclearites. Preliminary results of the searches for charged Q-balls are also presented.Comment: 20 pages, 9 EPS figures included with epsfi