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%0 Thesis
%A Schoenen, Sebastian
%T Discovery and characterization of a diffuse astrophysical muon neutrino flux with the iceCube neutrino observatory
%I RWTH Aachen University
%V Dissertation
%C Aachen
%M RWTH-2017-06715
%P 1 Online-Ressource (xix, 234 Seiten) : Illustrationen, Diagramme
%D 2017
%Z Veröffentlicht auf dem Publikationsserver der RWTH Aachen University
%Z Dissertation, RWTH Aachen University, 2017
%X The IceCube Collaboration has previously discovered a flux of high-energy astrophysical neutrinos whose measurement is based on events with interaction vertices contained within the IceCube detector. This thesis presents a complementary measurement of such a flux based on charged-current muon neutrino events whose interaction vertices can be outside the detector volume. Due to the large range of the induced muon the effective area is significantly larger but the field of view is restricted to the Northern Hemisphere. In this thesis IceCube data from 2009 through 2015 have been analyzed using a likelihood approach based on the reconstructed muon energy and zenith angle. The analyzed data consist of about 350,000 muon neutrinos with a negligible background of atmospheric muons where the majority of these events are atmospheric neutrinos. The here presented analysis improves the statistics compared to previous analyses by almost an order of magnitude. At the highest neutrino energies between 194 TeV and 7.8 PeV a significant astrophysical muon neutrino flux has been measured. While the data is incompatible with a purely atmospheric neutrino flux at 5.6 sigma significance, the data are well described by an isotropic, unbroken power-law flux with a normalization at 100 TeV neutrino energy of (0.90 +0.30-0.27) ∙ 10-18 GeV-1 cm-2 s-1 sr-1 and a hard spectral index of 2.13 +/- 0.13. The corresponding energy spectrum is harder compared to previous IceCube analyses with lower energy thresholds which may indicate a break in the astrophysical neutrino spectrum of unknown origin. The highest energy event observed has a reconstructed muon energy of (4.5+/-1.2) PeV which results in a median muon neutrino energy of 8.7 PeV based on the best-fit neutrino energy spectrum. The probability of this event being of atmospheric origin has been estimated to be less than 0.005
%F PUB:(DE-HGF)11
%9 Dissertation / PhD Thesis
%R 10.18154/RWTH-2017-06715
%U https://publications.rwth-aachen.de/record/696221