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

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 $\sim$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.

Submitted to Physical Review Letters as part of a joint submission with "Improved measurements of the TeV--PeV extragalactic neutrino spectrum from joint analyses of IceCube tracks and cascades" which has been submitted to Physical Review D

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• Improved measurements of the TeV-PeV extragalactic neutrino spectrum from joint analyses of IceCube tracks and cascades
• Proton Acceleration by Collisionless Shocks in Supermassive Black Hole Coronae: Implications for High-Energy Neutrinos
• Multimessenger Characterization of High-Energy Neutrino Emission from the Brightest Neutrino-Active Galactic Nuclei
• Revisiting Disk Winds in Active Galactic Nuclei as an Origin of Cosmic Gamma-ray and Neutrino Backgrounds
• A Unified Framework for 10 TeV to EeV Diffuse Neutrino Sky and KM3-230213A
• Neutrino Astronomy at High Energies - An Experimental Review