Neutrino Telescopes, installed deep under water or ice, rely on the detection of the showers or tracks produced by the neutral or charged current interactions of GeV to PeV neutrinos in the matter surrounding the detector. IceCube in the Antarctic ice, with its low energy extensions DeepCore and in the future PINGU, and ANTARES in the mediterranean sea, with its future extensions KM3NeT/ARCA for high energies, and KM3NeT/ORCA for low energies, consist in 3D arrays of photomultipliers sensitive to the Cherenkov light produced by the neutrino interaction products. The physics case for such telescopes is twofold. At high energy (TeV-PeV), the main objective is to identify the sources of high energy cosmic rays, mostly hadrons, through their neutrino emissions. At low energy (GeV), the use of atmospheric neutrinos will allow to determine the neutrino mass hierarchy.
This seminar will present the most recent results in Neutrino Astronomy, insisting on the first detection of high energy (TeV-PeV) cosmic neutrinos by IceCube, while the sources for this diffuse signal have not been identified yet. It will emphasize some of the constraints that Antares has been able to place on its origin. Its successor KM3NeT will allow to look for all-flavor neutrino signals with a better sensitivity than IceCube, its high energy component, ARCA (Astroparticle Research with Cosmics in the Abyss), focusing on the identification of these cosmic neutrino sources.
KM3NeT’s low energy component, ORCA (Oscillation Research with Cosmics in the Abyss) will focus on the determination of the neutrino mass hierarchy, a key element to understand the nature of neutrinos, which would help for future measurements of the CP phase. The KM3NeT collaboration has recently decided to dedicate available funds to the deployment of a 6-line demonstrator offshore Toulon, to validate the principle of a denser telescope to study the oscillations in matter of atmospheric neutrinos. The final detector composed of 115 strings could be completed as soon as 2019, opening the way towards the first measurement of the neutrino mass hierarchy. ORCA's baseline performances in terms of flavor identification, energy and angular accuracy, and background rejection will be presented.