Evidence for a Spectral Break or Curvature in the Spectrum of Astrophysical Neutrinos from 5 TeV to 10 PeV


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

PHYSICAL REVIEW LETTERS, vol.136, no.12, 2026 (SCI-Expanded, Scopus)

  • Publication Type: Article / Article
  • Volume: 136 Issue: 12
  • Publication Date: 2026
  • Doi Number: 10.1103/2gh9-d4q7
  • Journal Name: PHYSICAL REVIEW LETTERS
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Chemical Abstracts Core, Compendex, EMBASE, INSPEC, MathSciNet, MEDLINE, zbMATH, DIALNET
  • Open Archive Collection: AVESIS Open Access Collection
  • Middle East Technical University Affiliated: No

Abstract

We report improved measurements of the all flavor astrophysical neutrino spectrum with IceCube by combining complementary neutrino samples in two independent analyses. Both analyses show evidence of a harder spectrum at energies below similar to 30 TeV compared to higher energies where the spectrum is well characterized by a power law. The spectrum is better described by a log parabola or a broken power law, the latter being the preferred model. Both, however, reject a single power law over an energy range 5 TeV-10 PeV with a significance >4 sigma, providing new constraints on properties of cosmic neutrino sources.