Characterization of the Astrophysical Diffuse Neutrino Flux with IceCube High-Energy Starting Events

TL;DR

This paper presents an updated measurement of the astrophysical diffuse neutrino flux using IceCube's high-energy starting events over 7.5 years, analyzing compatibility with various flux models and finding no model significantly preferred.

Contribution

The study extends the IceCube neutrino flux analysis with more data, improved models, and systematic treatment, providing the most recent constraints on astrophysical neutrino flux models.

Findings

No significant preference for detailed isotropic flux models over simple power-law models.

Updated analysis with 7.5 years of data enhances the robustness of neutrino flux measurements.

Compatibility of observations with standard flux models is confirmed.

Abstract

The IceCube neutrino observatory has established the existence of an astrophysical diffuse neutrino component above $100$ TeV. This discovery was made using the high-energy starting event sample, which uses the outer layer of instrumented volume as a veto to significantly reduce atmospheric background. We present the latest astrophysical neutrino flux measurement using high-energy starting events. This latest iteration of the analysis extends the sample by $1.5$ years for a total of $7.5$ years, updates the event properties with newer models of light transport in the glacial ice, and has an improved systematic treatment. As part of this new analysis, we report on compatibility of our observations with detailed isotropic flux models proposed in the literature as well as the standard generic models such as single, double power-law scenarios. We find that none of the tested models are substantially preferred with respect to a single power law.