Speakers
Description
The Askaryan Radio Array (ARA) at the South Pole searches for ultra-high energy neutrinos through the detection of coherent radio emission generated by neutrino-induced cascades in Antarctic ice. We present a diffuse search for cosmogenic neutrinos using the complete five-station dataset collected between 2013 and 2023, corresponding to 26 station-years of analysis quality livetime.
This work unifies all stations and livetime configurations within a single array-wide framework. Waveforms are processed with a unified analysis pipeline across the array. Detector simulations include data-driven noise models, updated antenna and electronics gain treatments, and neutrino propagation with secondary interactions. Effective volumes are evaluated for each station configuration and combined coherently in the final sensitivity calculation. Background rejection proceeds in stages. After data quality and reconstruction cuts, a physics motivated fast filter suppresses incoherent thermal triggers at the waveform level. The final signal-background separation is performed using a multivariate linear discriminant trained on simulated neutrinos and a cleaned burn sample of data. The thermal cut is optimized array-wide to maximize discovery potential while maintaining strict control of expected background.
This analysis probes the EeV energy range where cosmogenic neutrinos are expected from interactions of ultra-high energy cosmic rays with the cosmic microwave background. We will present the analysis strategy, systematic uncertainties, projected sensitivity, and results from the unblinded dataset.