Search for Acoustic Signals from Ultra-High Energy Neutrinos in 1500 km^3 of Sea Water

TL;DR

This study employs a large underwater acoustic array to search for ultra-high energy neutrinos, analyzing extensive data to set the most sensitive flux limits using acoustic detection methods.

Contribution

It introduces a large-scale acoustic detection experiment with detailed sensitivity analysis and sets new upper limits on UHE neutrino fluxes.

Findings

Detected two candidate events consistent with ultra-high energy showers.

Established the most sensitive flux upper limits for UHE neutrinos with acoustic detection.

Demonstrated the feasibility of large-volume acoustic neutrino searches.

Abstract

An underwater acoustic sensor array spanning ~1500 km^3 is used to search for cosmic-ray neutrinos of ultra-high energies (UHE, E > 10^18 eV). Approximately 328 million triggers accumulated over an integrated 130 days of data taking are analysed. The sensitivity of the experiment is determined from a Monte Carlo simulation of the array using recorded noise conditions and expected waveforms. Two events are found to have properties compatible with showers in the energy range 10^24 to 5x10^24 eV and 10^22 to 5x10^22 eV. Since the understanding of impulsive backgrounds is limited, a flux upper limit is set providing the most sensitive limit on UHE neutrinos using the acoustic technique.