Uncertainties on Atmospheric Neutrino Flux Calculations

The strong evidence of new physics coming from atmospheric neutrino experiments has motivated a series of critical studies to test the robustness of the available flux calculations. In view of a more precise determination of the parameters of new physics, new and more refined flux calculations are in progress. Here we review the most important sources of theoretical uncertainties which affect these computations, and the attempts currently under way to improve them.Comment: Extended version of talk given at NOW2000, Conca Specchiulla, Otranto, Italy, Sep. 2000 Fig. 2 has been replace

A Minimal Object Oriented Real-Time Operating System in C++

Most embedded software is currently developed using the C programming language, even though its low level of abstrac- tion requires a lot of effort to the programmer. The C++ language is a better choice because: it raises the level of abstraction; it is strongly typed, so it prevents many com- mon programming mistakes; it can be made as efficient as C through fine-grained customisation of memory mechanisms; it can be easily adapted to domain-specific needs. In ad- dition, recent compilers have grown in maturity and per- formance, and the new standard considerably improves the language by introducing new concepts and an easier syntax. In this paper we present ADOK, a minimal Real-Time Op- erating System entirely written in C++ with the exception of a few lines of assembler code. It directly offers a C++ interface to the developer, and it provides a flexible schedul- ing framework which allows the developer to customise the scheduling to its needs. In particular, we implement a two- level scheduler based on Earliest Deadline First, the Stack Resource Policy protocol for sharing resources and support for mode changes. We demonstrate through examples and a small case-study that ADOK can substantially improve productivity without sacrificing on performance

Progresses in the validation of the FLUKA atmospheric neutrino flux calculations

The FLUKA calculation of the atmospheric neutrino fluxes have been cross-checked by comparing predictions on lepton fluxes in atmosphere to experimental data. The dependence of predicted neutrino fluxes on the shape and normalization of primary spectrum is also investigatedComment: Presented at TAUP2001 (Sep. 8-12, Assergi, Italy). 5 pages, 1 figur

A 3-Dimensional Calculation of Atmospheric Neutrino Flux

An extensive 3-dimensional Monte Carlo calculation of the atmospheric neutrino flux is in progress with the FLUKA Monte Carlo code. The results are compared to those obtained under the 1-dimensional approximation, where secondary particles and decay products are assumed to be collinear to the primary cosmic ray, as usually done in most of the already existing flux calculations. It is shown that the collinear approximation gives rise to a wrong angular distribution of neutrinos, essentially in the Sub-GeV region. However, the angular smearing introduced by the experimental inability of detecting recoils in neutrino interactions with nuclei is large enough to wash out, in practice, most of the differences between 3-dimensional and 1-dimensional flux calculations. Therefore, the use of the collinear approximation should have not introduced a significant bias in the determination of the flavor oscillation parameters in current experiments.Comment: 27 pages, 14 figures. To be submitted to Astroparticle Physics. To be submitted to Astroparticle Physic

A Monte Carlo Calculation of Atmospheric Muon and Neutrino Fluxes

Production of muons and neutrinos in cosmic ray interactions with the atmosphere has been investigated with a cascade simulation program based on Lund Monte Carlo programs. The resulting `conventional' muon and neutrino fluxes (from $\pi ,K$ decays) agree well with earlier calculations, whereas the improved charm particle treatment used in this study gives significantly lower `prompt' fluxes compared to earlier estimates. This implies better prospects for detecting very high energy neutrinos from cosmic sources.Comment: 4 pages, uuencoded and gziped ps-fil

SysRT: A Modular Multiprocessor RTOS Simulator for Early Design Space Exploration

International audienc

Comparison of 3-Dimensional and 1-Dimensional Schemes in the calculation of Atmospheric Neutrinos

A 3-dimensional calculation of atmospheric neutrinos flux is presented, and the results are compared with those of a 1-dimensional one. In this study, interaction and propagation of particles is treated in a 3-dimensional way including the curvature of charged particles due to the geomagnetic field, which is assumed to be a dipole field. The purpose of this paper is limited to the comparison of calculation schemes. The updated flux value with new interaction model and primary flux model will be reported in a separate paper. Except for nearly horizontal directions, the flux is very similar to the result of 1 dimensional calculations. However, for near-horizontal directions an enhancement of the neutrino flux is seen even at energies as high as 1 GeV. The production height of neutrinos is lower than the prediction by 1-dimensional calculation for near-horizontal directions, and is a little higher for near-vertical directions. However, the difference is not evident except for near-horizontal directions.Comment: 22 pages, 15figure

Extreme Galactic-Winds and Starburst in IR Mergers and IR QSOs

We report -as a part of a long-term study of mergers and IR QSOs- detailed spectroscopic evidences for outflow (OF) and/or Wolf Rayet features in: (i) low velocity OF in the ongoing mergers NGC 4038/39 and IRAS 23128-5919; (ii) extreme velocity OF (EVOF) in the QSOs IRAS 01003-2238 and IRAS 13218+0552; (iii) OF and EVOF in a complete sample of ultra-luminous IR galaxies/QSOs ("The IRAS 1 Jy MKO-KPNO Survey", of 118 objects). We found EVOF in IRAS 11119+3257, 14394+5332, 15130+1958 and 15462-0450. The OF components detected in these objects were mainly associated to starburst processes: i.e., to galactic-winds generated in multiple type II SN explosions and massive stars. The EVOF were detected in objects with strong starburst plus obscured IR QSOs; which suggest that interaction of both processes could generate EVOF. In addition, we analyze the presence of Wolf Rayet features in the large sample of Bright PG-QSOs (Boroson and Green 1992), and nearby mergers and galactic-wind galaxies. We found clear WR features in the Fe II QSOs (type I): PG 1244+026, 1444+407, 1448+273, 1535+547; and in the IR merger Arp 220. HST archive images of IR+BAL QSOs show in practically all of these objects "arc or shell" features probably associated to galactic-winds (i.e., to multiple type II SN explosions) and/or merger processes. Finally, we discuss the presence of extreme starburst and galactic wind as a possible evolutive link between IR merger and IR QSOs; where the relation between mergers and extreme starburst (with powerful galactic-winds) plays in important role, in the evolution of galaxies.Comment: 14 pages, 6 figure