First Neutrino Point-Source Results From The 22 String Icecube Detector

We present new results of searches for neutrino point sources in the northern sky, using data recorded in 2007-2008 with 22 strings of the IceCube detector (approximately one-fourth of the planned total) and 275.7 days of live time. The final sample of 5114 neutrino candidate events agrees well with the expected background of atmospheric muon neutrinos and a small component of atmospheric muons. No evidence of a point source is found, with the most significant excess of events in the sky at 2.2 sigma after accounting for all trials. The average upper limit over the northern sky for point sources of muon-neutrinos with E-2 spectrum is E-2 Phi(v mu) < 1.4 x 10(-11) TeV cm(-2) s(-1), in the energy range from 3 TeV to 3 PeV, improving the previous best average upper limit by the AMANDA-II detector by a factor of 2.

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Xiaoxia Bai, Shirit Cohen, Levent Demirörs, Mathieu Ribordy
2009
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https://infoscience.epfl.ch/record/154499?ln=fr

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Search for ultra-high-energy neutrinos with AMANDA-II

Xiaoxia Bai, Levent Demirörs, Mathieu Ribordy, Yi Wang

A search for diffuse neutrinos with energies in excess of 105 GeV is conducted with AMANDA-II data recorded between 2000 and 2002. Above 107 GeV, the Earth is essentially opaque to neutrinos. This fact, combined with the limited overburden of the AMANDA-II detector (roughly 1.5 km), concentrates these ultra-high-energy neutrinos at the horizon. The primary background for this analysis is bundles of downgoing, high-energy muons from the interaction of cosmic rays in the atmosphere. No statistically significant excess above the expected background is seen in the data, and an upper limit is set on the diffuse all-flavor neutrino flux of E2Φ 90%Cl < 2.7 × 10-7 GeV cm-2 s -1 sr-1 valid over the energy range of 2 × 10 5 to 109 GeV. A number of models that predict neutrino fluxes from active galactic nuclei are excluded at the 90% confidence level. © 2008. The American Astronomical Society. All rights reserved.

2008

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The design and performance of IceCube DeepCore

Xiaoxia Bai, Shirit Cohen, Mathieu Ribordy, Matthias Wolf

The IceCube neutrino observatory in operation at the South Pole, Antarctica, comprises three distinct components: a large buried array for ultrahigh energy neutrino detection, a surface air shower array, and a new buried component called DeepCore. DeepCore was designed to lower the IceCube neutrino energy threshold by over an order of magnitude, to energies as low as about 10 GeV. DeepCore is situated primarily 2100 m below the surface of the icecap at the South Pole, at the bottom center of the existing IceCube array, and began taking physics data in May 2010. Its location takes advantage of the exceptionally clear ice at those depths and allows it to use the surrounding IceCube detector as a highly efficient active veto against the principal background of downward-going muons produced in cosmic-ray air showers. DeepCore has a module density roughly five times higher than that of the standard IceCube array, and uses photomultiplier tubes with a new photocathode featuring a quantum efficiency about 35% higher than standard IceCube PMTs. Taken together, these features of DeepCore will increase IceCube's sensitivity to neutrinos from WIMP dark matter annihilations, atmospheric neutrino oscillations, galactic supernova neutrinos, and point sources of neutrinos in the northern and southern skies. In this paper we describe the design and initial performance of DeepCore. (c) 2012 Elsevier B.V. All rights reserved.

2012

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Search for Dark Matter Annihilations in the Sun with the 79-String IceCube Detector

Xiaoxia Bai, Shirit Cohen, Mathieu Ribordy, Matthias Wolf

We have performed a search for muon neutrinos from dark matter annihilation in the center of the Sun with the 79-string configuration of the IceCube neutrino telescope. For the first time, the DeepCore subarray is included in the analysis, lowering the energy threshold and extending the search to the austral summer. The 317 days of data collected between June 2010 and May 2011 are consistent with the expected background from atmospheric muons and neutrinos. Upper limits are set on the dark matter annihilation rate, with conversions to limits on spin-dependent and spin-independent scattering cross sections of weakly interacting massive particles (WIMPs) on protons, for WIMP masses in the range 20-5000 GeV=c(2). These are the most stringent spin-dependent WIMP-proton cross section limits to date above 35 GeV=c(2) for most WIMP models. DOI: 10.1103/PhysRevLett.110.131302

American Physical Society2013

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Muon neutrino

The muon neutrino is an elementary particle which has the symbol Muon neutrino and zero electric charge. Together with the muon it forms the second generation of leptons, hence the name mu

IceCube

LObservatoire de neutrinos IceCube, ou simplement IceCube, « cube de glace », est un observatoire de neutrinos construit au pôle Sud. Ses milliers de capteurs sont situés sous la glace antarctique,

Observatoire de neutrinos

thumb|Intérieur de , un détecteur de neutrinos lancé en 2002. Un observatoire de neutrinos est un dispositif permettant de détecter les neutrinos. En raison de la très faible interaction des neutrinos