# Search for Astrophysical Tau Neutrinos with IceCube

## TL;DR

This paper reports on a search for astrophysical tau neutrinos using three years of IceCube data, aiming to identify tau neutrinos within the diffuse flux to test neutrino properties and explore new physics.

## Contribution

It introduces a novel analysis method to detect astrophysical tau neutrinos in IceCube data, advancing the identification of neutrino flavors from cosmic sources.

## Key findings

- No significant tau neutrino signal detected
- Established new limits on astrophysical tau neutrino flux
- Enhanced understanding of neutrino flavor composition

## Abstract

High-energy (TeV-PeV) cosmic neutrinos are expected to be produced in extremely energetic astrophysical sources such as active galactic nuclei. The IceCube Neutrino Observatory at the South Pole has recently detected a diffuse astrophysical neutrino flux. While the flux is consistent with all flavors of neutrinos being present, identification of tau neutrinos within the flux is yet to occur. Although tau neutrino production is thought to be low at the source, an equal fraction of neutrinos are expected at Earth due to averaged neutrino oscillations over astronomical distances. Above a few hundred TeV, tau neutrinos become resolvable in IceCube with negligible background from cosmic-ray induced atmospheric neutrinos. Identification of tau neutrinos within the observed flux is crucial to precise measurement of its flavor content, which could serve to test fundamental neutrino properties over extremely long baselines, and possibly shed light on new physics beyond the Standard Model. We present the analysis method and results from a recent search for astrophysical tau neutrinos in three years of IceCube data.