Astrophysical Tau Neutrino Identification with IceCube Waveforms

TL;DR

This paper presents a method to identify astrophysical tau neutrinos in IceCube data by detecting double energy depositions in waveforms, improving the understanding of neutrino flavor composition and testing physics beyond the Standard Model.

Contribution

The study introduces an improved waveform analysis technique to identify tau neutrinos in IceCube data, enabling more precise flavor ratio measurements.

Findings

Successful identification of tau neutrino candidates

Enhanced waveform analysis method demonstrated

Implications for neutrino physics and astrophysics

Abstract

The standard neutrino oscillation paradigm predicts almost equal fractions of astrophysical neutrino flavors at Earth regardless of their production ratio at the sources. Therefore, identification of astrophysical tau neutrinos could not only reconfirm the astrophysical neutrino flux measured by IceCube, but also is essential in precisely determining the astrophysical neutrino flavor ratio at Earth, which is an important probe for physics beyond the Standard Model over astronomical baselines. A tau neutrino undergoing a charged current (CC) interaction in IceCube could produce a double deposition of energy, with the first one from the CC hadronic shower and the second from the subsequent tau lepton decay shower. Above an energy of ~100 TeV, such consecutive energy depositions might be resolvable in the sensor waveforms and hence can be a signature of an individual tau neutrino interaction in IceCube. We will present the results of a search for astrophysical tau neutrinos in IceCube waveforms with improved double pulse waveform identification techniques and using 8 years of data.