Characterization of the astrophysical diffuse neutrino flux using starting track events in IceCube


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Abbasi R., Ackermann M., Adams J., Agarwalla S. K., Aguilar J. A., Ahlers M., ...More

PHYSICAL REVIEW D, vol.110, no.2, 2024 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 110 Issue: 2
  • Publication Date: 2024
  • Doi Number: 10.1103/physrevd.110.022001
  • Journal Name: PHYSICAL REVIEW D
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Aerospace Database, Chemical Abstracts Core, INSPEC, zbMATH, Nature Index
  • Middle East Technical University Affiliated: No

Abstract

A measurement of the diffuse astrophysical neutrino spectrum is presented using IceCube data collected from 2011-2022 (10.3 years). We developed novel detection techniques to search for events with a contained vertex and exiting track induced by muon neutrinos undergoing a charged-current interaction. Searching for these starting track events allows us to not only more effectively reject atmospheric muons but also atmospheric neutrino backgrounds in the southern sky, opening a new window to the sub-100 TeV astrophysical neutrino sky. The event selection is constructed using a dynamic starting track veto and machine learning algorithms. We use this data to measure the astrophysical diffuse flux as a single power law flux (SPL) with a best-fit spectral index of gamma = 2.58(-0.09)(+0.10) and per-flavor normalization of phi(Astro)(per-flavor) phi 1.68(-0.22)(+0.19) x 10(-18) x GeV-1 cm(-2) s(-1) sr(-1) (at 100 TeV). The sensitive energy range for this dataset is 3-550 TeV under the SPL assumption. This data was also used to measure the flux under a broken power law, however we did not find any evidence of a low energy cutoff.