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First Observation of PeV-energy Neutrinos with IceCube

par Aartsen, M. G.;Bechet, Sabrina ;Bertrand, Daniel ;Hanson, Kael ;Heereman von Zuydtwyck, David ;Meures, Thomas ;O'Murchadha, Aongus ;Pinat, Elisa ;Toscano, Simona ; [et al.]
Référence Physical review letters
Publication Publié, 2013-06-11

Article révisé par les pairs

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Résumé :

We report on the observation of two neutrino-induced events which have an estimated deposited energy in the IceCube detector of 1.04±0.16 and 1.14±0.17 PeV, respectively, the highest neutrino energies observed so far. These events are consistent with fully contained particle showers induced by neutral-current νe,μ,τ (ν ̄e,μ,τ) or charged-current νe (ν̄e) interactions within the IceCube detector. The events were discovered in a search for ultrahigh energy neutrinos using data corresponding to 615.9 days effective live time. The expected number of atmospheric background is 0.082±0.004(stat)-0.057+0.041(syst). The probability of observing two or more candidate events under the atmospheric background-only hypothesis is 2.9×10-3 (2.8σ) taking into account the uncertainty on the expected number of background events. These two events could be a first indication of an astrophysical neutrino flux; the moderate significance, however, does not permit a definitive conclusion at this time. © 2013 American Physical Society.