1,729 research outputs found
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 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
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