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

2025/07/29 by R. Abbasi, Abbasi, R., M. Ackermann +878 · 1 voice · 8 citations
Physics and Astronomy · #Astrophysics and Cosmic Phenomena #Neutrino Physics Research #Particle physics theoretical and experimental studies

paper · pdf · doi:10.1103/2gh9-d4q7

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 ∼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 >4σ, providing new constraints on properties of cosmic neutrino sources.

Citations

• The Large-Sample Distribution of the Likelihood Ratio for Testing Composite Hypotheses

Cited by

• Revisiting Disk Winds in Active Galactic Nuclei as an Origin of Cosmic Gamma-Ray and Neutrino Backgrounds
• Validating the performance of the Radio Neutrino Observatory in Greenland using cosmic-ray air showers
• Exploring New Propagation Scales With Galactic Neutrinos
• Possible ν Source Class: 3-sigma Detection of High-Energy Neutrinos from Supermassive Black Hole Binary Candidates
• Characterization of the Three-Flavor Composition of Cosmic Neutrinos with IceCube
• Evidence for Neutrino Emission from X-ray Bright Active Galactic Nuclei with IceCube
• Extreme High-Energy Neutrinos: IceCube vs. KM3NeT
• Improved measurements of the TeV--PeV extragalactic neutrino spectrum from joint analyses of IceCube tracks and cascades

Discussions

• For those who like to know how the sausage gets made: Here is the full, hairy paper describing how scientists caught & measured a whole bunch of passing neutrinos. 🧪🔭 arxiv.org/abs/2507.22233 [bsky, 21 points, 2 comments]

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