3,813 research outputs found
The SuperNova Early Warning System
A core collapse in the Milky Way will produce an enormous burst of neutrinos
in detectors world-wide. Such a burst has the potential to provide an early
warning of a supernova's appearance. I will describe the nature of the signal,
the sensitivity of current detectors, and SNEWS, the SuperNova Early Warning
System, a network designed to alert astronomers as soon as possible after the
detected neutrino signal.Comment: 3 pages, appearing in refereed proceedings of "Hotwiring the
Transient Universe 2007", eds. A. Allan, J. S. Bloom, R. Seaman, Astron.
Nachr. vol. 329, March 200
MONOLITH: a next generation experiment for athospheric neutrinos
MONOLITH is a massive magnetized tracking calorimeter, optimized for the
detection of atmospheric muon neutrinos, proposed at the Gran Sasso laboratory
in Italy. The main goal is to establish (or reject) the neutrino oscillation
hypothesis through an explicit observation of the full first oscillation swing
(the ``L/E pattern''). Its performance, status and prospects are briefly
reviewed.Comment: Talk given at Europhysics Neutrino Oscillation Workshop (NOW2000),
Otranto, Italy, September 9-16, 2000 (4 pages, 3 figures
Detector Time Offset and Off-line Calibration in EAS Experiments
In Extensive Air Shower (EAS) experiments, the primary direction is
reconstructed by the space-time pattern of secondary particles. Thus the
equalization of the transit time of signals coming from different parts of the
detector is crucial in order to get the best angular resolution and pointing
accuracy allowed by the detector. In this paper an off-line calibration method
is proposed and studied by means of proper simulations. It allows to calibrate
the array repeatedly just using the collected data without disturbing the
standard acquisition. The calibration method is based on the definition of a
Characteristic Plane introduced to analyze the effects of the time systematic
offsets, such as the quasi-sinusoidal modulation on azimuth angle distribution.
This calibration procedure works also when a pre-modulation on the primary
azimuthal distribution is present.Comment: 9 pages, 5 figures, submitted to Astroparticle Physic
Spectra of hadrons and muons in the atmosphere: primary spectra, characteristics of hadron-air interactions
Self-consistency of interaction models QGSJET 01, SIBYLL 2.1, NEXUS 3.97 and
QGSJET II is checked in terms of their ability to reproduce simultaneously
experimental data on fluxes of muons and hadrons. From this point of view
SIBYLL 2.1 gives the most acceptable, though not quite satisfactory, results.
Analysis of the situation for muons supports our previous conclusions, that
high-energy muon deficit is due both to underestimation of primary light nuclei
fluxes in direct emulsion chamber experiments and to softness of
inclusive spectra in fragmentation region, especially
prominent in case of QGSJET 01 model.Comment: Talk given at the XIVth ISVHECRI (Weihai, China, 2006
The Crux of the Matter: Ratings and Credit Risk Valuation at the heart of the Structured Finance Crisis
The 2007/2008 global credit crisis was born out of opaque securitization transactions. Introducing structured products risk estimation techniques shows how the most basic investment analysis could not be done without detailed and updated knowledge on the assets of the pool. Access to such details was crucial for investors to perform an autonomous valuation, the lack of which led to a pervading acceptance of ratings at face value. The crisis brought numerous delusions to naĂŻve users of these privately issued opinions. Coming back to the central role that investor played during the previous speculative episode and introducing a theoretical discussion on the dynamics of market finance, it is shown that trusting market discipline and due diligence was bound to end up being misguiding. Given that unprecedented rating volatility brought a share of the blame game to rating firms, strategies that would aim at securing an informed use of ratings are finally outlined.financial crisis, credit risk, rating agencies
Muon simulation codes MUSIC and MUSUN for underground physics
The paper describes two Monte Carlo codes dedicated to muon simulations:
MUSIC (MUon SImulation Code) and MUSUN (MUon Simulations UNderground). MUSIC is
a package for muon transport through matter. It is particularly useful for
propagating muons through large thickness of rock or water, for instance from
the surface down to underground/underwater laboratory. MUSUN is designed to use
the results of muon transport through rock/water to generate muons in or around
underground laboratory taking into account their energy spectrum and angular
distribution.Comment: 22 pages, 9 figures, 1 table, to be published in Computer Physics
Communication
The cosmic ray primary composition in the ?knee? region through the EAS electromagnetic and muon measurements at EAS-TOP
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Cosmic rays measurements around the knee of the primary spectrum
In this contribution I will summarize and discuss some recent results about the study of the knee of the cosmic rays energy spectrum, indicating that this spectral feature is originated by astrophysical processes. I will then discuss the current experimental efforts that are giving further insights. Latest all particle spectrum measurements have shown that, between 1016eV and 1018eV, the spectrum cannot be described by a single slope power law: an hardening around 1016eV and a steepeningaround 1017eV have been observed. This last feature has been attributed, by the KASCADE-Grande experiment, to the heavy primary component, confirming that the energy of the elemental spectra change of slope increase with the mass of the primary particle
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