Atmospheric neutrino data : Active-Active ×\times Active-Sterile oscillations

I summarize here the results of a global fit to the full data set corresponding to 33.0 kt-yr of data of the Super-Kamiokande experiment as well as to all other experiments in order to compare the active-active and active-sterile neutrinos oscillation channels to the atmospheric neutrino anomaly.Comment: 3 pages, uses espcrc2.sty (Nuclear Physics style) and epsfig.sty, 2 PS files. To appear in the Proceedings of the XTH Int. Symposium on Very High Energy Cosmic Ray Interactions, Laboratory Nazionali del Gran Sasso, Assergi, Italy, July 12-17 199

Atmospheric Neutrinos

The results of experiments on atmospheric neutrinos are summarized, with the important exception of Superkamiokande. The main emphasis is given to the Soudan-2 and MACRO experiments. Both experiments observe atmospheric neutrino anomalies in agreement with nu_mu-->> nu_tau oscillations with maximum mixing. The nu_mu-->> nu_sterile oscillation is disfavored by the MACRO experiment.Comment: To be published in the proceedings of TAUP99 Conference College de France - Paris 6-10 September 1999 11 pages 12 figure

Measurements of the Cosmic Ray Composition with Air Shower Experiments

In this paper we review air shower data related to the mass composition of cosmic rays above 10$^{15}$ eV. After explaining the basic relations between air shower observables and the primary mass and energy of cosmic rays, we present different approaches and results of composition studies with surface detectors. Furthermore, we discuss measurements of the longitudinal development of air showers from non-imaging Cherenkov detectors and fluorescence telescopes. The interpretation of these experimental results in terms of primary mass is highly susceptible to the theoretical uncertainties of hadronic interactions in air showers. We nevertheless attempt to calculate the logarithmic mass from the data using different hadronic interaction models and to study its energy dependence from 10$^{15}$ to 10$^{20}$ eV.Comment: 21 pages, invited review accepted for publication in Astroparticle Physics, Topical Issue on Cosmic Ray

The primary cosmic ray composition between 10**15 and 10**16 eV from Extensive Air Showers electromagnetic and TeV muon data

The cosmic ray primary composition in the energy range between 10**15 and 10**16 eV, i.e., around the "knee" of the primary spectrum, has been studied through the combined measurements of the EAS-TOP air shower array (2005 m a.s.l., 10**5 m**2 collecting area) and the MACRO underground detector (963 m a.s.l., 3100 m w.e. of minimum rock overburden, 920 m**2 effective area) at the National Gran Sasso Laboratories. The used observables are the air shower size (Ne) measured by EAS-TOP and the muon number (Nmu) recorded by MACRO. The two detectors are separated on average by 1200 m of rock, and located at a respective zenith angle of about 30 degrees. The energy threshold at the surface for muons reaching the MACRO depth is approximately 1.3 TeV. Such muons are produced in the early stages of the shower development and in a kinematic region quite different from the one relevant for the usual Nmu-Ne studies. The measurement leads to a primary composition becoming heavier at the knee of the primary spectrum, the knee itself resulting from the steepening of the spectrum of a primary light component (p, He). The result confirms the ones reported from the observation of the low energy muons at the surface (typically in the GeV energy range), showing that the conclusions do not depend on the production region kinematics. Thus, the hadronic interaction model used (CORSIKA/QGSJET) provides consistent composition results from data related to secondaries produced in a rapidity region exceeding the central one. Such an evolution of the composition in the knee region supports the "standard" galactic acceleration/propagation models that imply rigidity dependent breaks of the different components, and therefore breaks occurring at lower energies in the spectra of the light nuclei.Comment: Submitted to Astroparticle Physic

Active-active and active-sterile neutrino oscillation solutions to the atmospheric neutrino anomaly

We perform a fit to the full data set corresponding to 33.3 kt-yr of data of the Super-Kamiokande experiment as well as to all other experiments in order to compare the two most likely solutions to the atmospheric neutrino anomaly in terms of oscillations in the $\nu_\mu \to \nu_\tau$ and $\nu_\mu \to \nu_s$ channels. Using state-of-the-art atmospheric neutrino fluxes we have determined the allowed regions of oscillation parameters for both channels. We find that the $\Delta m^2$ values for the active-sterile oscillations (both for positive and negative $\Delta m^2$) are higher than for the $\nu_\mu \to \nu_\tau$ case, and that the increased Super-Kamiokande sample slightly favours $\nu_\mu \to \nu_\tau$ oscillations over oscillations into a sterile species $\nu_s$, $\nu_\mu \to \nu_s$, and disfavours $\nu_\mu \to \nu_e$. We also give the zenith angle distributions predicted for the best fit points in each of the possible oscillation channels. Finally we compare our determinations of the atmospheric neutrino oscillation parameters with the expected sensitivities of future long-baseline experiments K2K, MINOS, ICARUS, OPERA and NOE.Comment: Updated to 535 days of Super-Kamiokande and corresponding modifications in the discussion and figures. Some References adde

Atmospheric neutrino observations and flavor changing interactions

Flavor changing (FC) neutrino-matter interactions can account for the zenith-angle dependent deficit of atmospheric neutrinos observed in the SuperKamiokande experiment, without directly invoking neither neutrino mass, nor mixing. We find that FC $\nu_\mu$-matter interactions provide a good fit to the observed zenith angle distributions, comparable in quality to the neutrino oscillation hypothesis. The required FC interactions arise naturally in many attractive extensions of the Standard Model.Comment: RevTex, 4 pages, 2 postscript figures, some minor modifications in the text and few new references are added, no change in the results and conclusions, final version to be published in Phys. Rev. Let

SNEWS: The SuperNova Early Warning System

This paper provides a technical description of the SuperNova Early Warning System (SNEWS), an international network of experiments with the goal of providing an early warning of a galactic supernova.Comment: 25 pages, for New Journal of Physics Focus Issue on Neutrino Physic

Search for diffuse neutrino flux from astrophysical sources with MACRO

Many galactic and extragalactic astrophysical sources are currently considered promising candidates as high energy neutrino emitters. Astrophysical neutrinos can be detected as upward-going muons produced in charged-current interactions with the medium surrounding the detector. The expected neutrino fluxes from various models start to dominate on the atmospheric neutrino background at neutrino energies above some tens of TeV. We present the results of a search for an excess of high energy upward-going muons among the sample of data collected by MACRO during ~5.8 years of effective running time. No significant evidence for this signal was found. As a consequence, an upper limit on the flux of upward-going muons from high-energy neutrinos was set at the level of 1.7 10^(-14) cm^(-2) s^(-1) sr^(-1). The corresponding upper limit for the diffuse neutrino flux was evaluated assuming a neutrino power law spectrum. Our result was compared with theoretical predictions and upper limits from other experiments.Comment: 19 pages, 8 figures, 2 table

Estado, escolas e famílias: públicos escolares e regulação da educação

O texto apresenta alguns resultados de uma investigação recentemente concluída que, genericamente, se inscreve nos complexos processos de (multi)regulação da educação. O estudo desenvolveu-se num concelho do norte de Portugal (convencionalmente designado Vila Formosa), circunscrevendo-se às escolas com oferta de ensino secundário. A análise dos dados sugere que, na topografia complexa dos processos de (multi)regulação do campo escolar, a combinação de medidas de política educativa com recursos e cursos de acção que as diferentes escolas e as diversas categorias de famílias e jovens detêm e adoptam constituem uma tríade de fontes de dinâmicas, umas vezes convergentes, outras vezes em tensão que, por seus efeitos sociológicos cumulativos, geram a reordenação do campo de lutas concorrenciais em torno da educação, lutas essas que parecem penalizar sobretudo as famílias que já sofrem de outras desvantagens.The text presents some results of a recently concluded investigation that, generically, is part of the complex processes of the (multi) regulation of education. The study was developed in a district in the north of Portugal (conventionally designated Vila Formosa) and was limited to schools that offered secondary education. The analysis of the data suggests that, in the complex topography of the processes of (multi)regulation of the school field, the combination of measures of educational policy with resources and courses of action that the different schools and the diverse categories of families and young people possess and adopt constitute a triad of dynamic sources, sometimes convergent and sometimes tense, that, by their cumulative sociological effects, generate the re-ordination of the field of competing struggles in education that seem to penalize, above all, the families that already suffer other disadvantages.El texto presenta algunos resultados de una investigación recientemente finalizada que, genéricamente, se inscribe en los complexos procesos de (multi) regulación de la educación. El estudio se desarrolló en un consejo del norte de Portugal (asignado convencionalmente Vila Formosa), circunscribiéndose a las escuelas con oferta de enseñanza secundaria. El análisis de los datos sugiere que, en la compleja topografía de los procesos de (multi)regulación del campo escolar, la combinación de medidas de política educativa con los recursos y los cursos de acción que las diferentes escuelas y las diversas categorías de familias y jóvenes retienen y que adoptan, constituyen una tríada de fuentes de dinámicas, unas veces convergentes, otras veces en tensión que, por sus efectos sociológicos acumulativos, generan la reordenación del campo de luchas competitivas alrededor de la educación y de los resultados de esas luchas que parecen penalizar principalmente a las familias que ya sufren de otras desventajas.(undefined