Study of acoustic neutrino detection in O$\nu$DE-2 raw acoustic data

TL;DR

This paper evaluates the potential of using deep-sea hydrophone data to detect acoustic signals from ultra-high-energy neutrino interactions, by testing a trigger system with synthetic signals added to real data.

Contribution

It introduces a method to assess neutrino-induced acoustic signal detection using existing hydrophone data and synthetic pulse injection for performance evaluation.

Findings

Synthetic bipolar pulses can be detected in real hydrophone data.

The study provides a framework for evaluating detection precision and recall.

Results suggest feasibility of acoustic neutrino detection with current underwater infrastructure.

Abstract

Research suggests that acoustic technology may be able to detect ultra-high-energy neutrinos if a large amount of non-linear fluid is analyzed. When a neutrino interacts in water, it creates a quasi-instantaneous cascade of particles, heating that region of the fluid and emitting a tiny acoustic signal. This rapid heating produces a thermoacoustic Bipolar Pulse (BP) with unique characteristics such as a wide bandwidth and a narrow directivity for these frequencies. While dedicated devices for acoustic neutrino detection are currently non-existent, there are a few underwater neutrino telescopes that utilize optical technology, but often with an acoustic positioning system that deploys hydrophones in the infrastructure. The possibility of using them to study a BP caused by a neutrino interaction is currently being discussed. This study aims to evaluate the implementation of a trigger system to detect a possible BP in deep-sea hydrophones. For this, up to 24 hours of the raw acoustic signal recorded by the O$\nu$DE-2 station, which was located 25 km off-shore from Catania in the Western Ionian Sea, at 2100 m depth, is analyzed. The station used calibrated hydrophones from a few Hz to 70 kHz. In this work, a synthetic BP is created and added to the experimental data, allowing the study of its detection and the calculation of precision and recall.