392 research outputs found
Sensitivity studies for the cubic-kilometre deep-sea neutrino telescope KM3NeT
The observation of high-energy neutrinos from astrophysical sources would
substantially improve our knowledge and understanding of the non-thermal
processes in these sources, and would in particular pinpoint the accelerators
of cosmic rays. The sensitivity of different design options for a future
cubic-kilometre scale neutrino telescope in the Mediterranean Sea is
investigated for generic point sources and in particular for some of the
galactic objects from which TeV gamma emmission has recently been observed by
the H.E.S.S. atmospheric Cherenkov telescope. The effect of atmospheric
background on the source detection probabilities has been taken into account
through full simulation. The estimated event rates are compared to previous
results and limits from present neutrino telescopes.Comment: 4 pages, 1 figure, contribution of the 30th International Cosmic Ray
conferenc
Draw me a Neutrino: the first KM3NeT art contest
[EN] While the KM3NeT neutrino detector is being deployed in the Mediterranean Sea, the Collaboration
launched a contest searching for illustrations of the neutrinos it will detect. The participants
in the contest were invited to submit their interpretation of a neutrino, using any technique. More
than 500 drawings were submitted from sixteen different countries. The winners were selected
by a jury of scientists, artists and science communicators based on the originality and creativity
of the drawings, as well as the harmony with the properties and origin of the neutrinos. After
announcing the results in an online ceremony with a large international audience, the winning
drawings have been put on display in a dedicated KM3NeT Virtual Neutrino Art Centre. In this
contribution, we will explain the motivation for the contest and will describe how it was organized.
We will also show the winning drawings and present the results of an impact study carried out
during the contest.We thank Angelo Ceres of Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Bari, for
setting up the contest website. The contest was supported in France from Centre National de la
Recherche Scientifique (CNRS) and LabEx UnivEarthS (ANR-10-LABX-0023 and ANR-18-IDEX0001). G. de Wasseige acknowledges support from the European Union¿s Horizon 2020 research
and innovation programme under the Marie Sklodowska-Curie grant agreement No 844138.Circella, M.; Ardid Ramírez, M.; Bendahman, M.; Bozza, C.; Coyle, P.; Wasseige, G.; Distefano, C.... (2022). Draw me a Neutrino: the first KM3NeT art contest. PoS. Proceedings of Science. 1-10. https://doi.org/10.22323/1.395.140011
Performance of the First ANTARES Detector Line
In this paper we report on the data recorded with the first Antares detector
line. The line was deployed on the 14th of February 2006 and was connected to
the readout two weeks later. Environmental data for one and a half years of
running are shown. Measurements of atmospheric muons from data taken from
selected runs during the first six months of operation are presented.
Performance figures in terms of time residuals and angular resolution are
given. Finally the angular distribution of atmospheric muons is presented and
from this the depth profile of the muon intensity is derived.Comment: 14 pages, 9 figure
Evidence for Quark-Hadron Duality in the Proton Spin Asymmetry
Spin-dependent lepton-nucleon scattering data have been used to investigate
the validity of the concept of quark-hadron duality for the spin asymmetry
. Longitudinally polarised positrons were scattered off a longitudinally
polarised hydrogen target for values of between 1.2 and 12 GeV and
values of between 1 and 4 GeV. The average double-spin asymmetry in
the nucleon resonance region is found to agree with that measured in
deep-inelastic scattering at the same values of the Bjorken scaling variable
. This finding implies that the description of in terms of quark
degrees of freedom is valid also in the nucleon resonance region for values of
above 1.6 GeV.Comment: 5 pages, 1 eps figure, table added, new references added, in print in
Phys. Rev. Let
Nuclear Polarization of Molecular Hydrogen Recombined on a Non-metallic Surface
The nuclear polarization of molecules formed by recombination
of nuclear polarized H atoms on the surface of a storage cell initially coated
with a silicon-based polymer has been measured by using the longitudinal
double-spin asymmetry in deep-inelastic positron-proton scattering. The
molecules are found to have a substantial nuclear polarization, which is
evidence that initially polarized atoms retain their nuclear polarization when
absorbed on this type of surfac
Flavor decomposition of the sea quark helicity distributions in the nucleon from semi-inclusive deep-inelastic scattering
Double-spin asymmetries of semi-inclusive cross sections for the production
of identified pions and kaons have been measured in deep-inelastic scattering
of polarized positrons on a polarized deuterium target. Five helicity
distributions including those for three sea quark flavors were extracted from
these data together with re-analyzed previous data for identified pions from a
hydrogen target. These distributions are consistent with zero for all three sea
flavors. A recently predicted flavor asymmetry in the polarization of the light
quark sea appears to be disfavored by the data.Comment: 5 pages, 3 figure
Acoustic and optical variations during rapid downward motion episodes in the deep north-western Mediterranean Sea
An Acoustic Doppler Current Profiler (ADCP) was moored at the deep-sea site
of the ANTARES neutrino telescope near Toulon, France, thus providing a unique
opportunity to compare high-resolution acoustic and optical observations
between 70 and 170 m above the sea bed at 2475 m. The ADCP measured downward
vertical currents of magnitudes up to 0.03 m s-1 in late winter and early
spring 2006. In the same period, observations were made of enhanced levels of
acoustic reflection, interpreted as suspended particles including zooplankton,
by a factor of about 10 and of horizontal currents reaching 0.35 m s-1. These
observations coincided with high light levels detected by the telescope,
interpreted as increased bioluminescence. During winter 2006 deep dense-water
formation occurred in the Ligurian subbasin, thus providing a possible
explanation for these observations. However, the 10-20 days quasi-periodic
episodes of high levels of acoustic reflection, light and large vertical
currents continuing into the summer are not direct evidence of this process. It
is hypothesized that the main process allowing for suspended material to be
moved vertically later in the year is local advection, linked with topographic
boundary current instabilities along the rim of the 'Northern Current'.Comment: 30 pages, 7 figure
The ANTARES Optical Beacon System
ANTARES is a neutrino telescope being deployed in the Mediterranean Sea. It
consists of a three dimensional array of photomultiplier tubes that can detect
the Cherenkov light induced by charged particles produced in the interactions
of neutrinos with the surrounding medium. High angular resolution can be
achieved, in particular when a muon is produced, provided that the Cherenkov
photons are detected with sufficient timing precision. Considerations of the
intrinsic time uncertainties stemming from the transit time spread in the
photomultiplier tubes and the mechanism of transmission of light in sea water
lead to the conclusion that a relative time accuracy of the order of 0.5 ns is
desirable. Accordingly, different time calibration systems have been developed
for the ANTARES telescope. In this article, a system based on Optical Beacons,
a set of external and well-controlled pulsed light sources located throughout
the detector, is described. This calibration system takes into account the
optical properties of sea water, which is used as the detection volume of the
ANTARES telescope. The design, tests, construction and first results of the two
types of beacons, LED and laser-based, are presented.Comment: 21 pages, 18 figures, submitted to Nucl. Instr. and Meth. Phys. Res.
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