High-Fidelity Simulations of the Full Askaryan Radio Array and its Sensitivity to Ultra-High Energy Neutrinos

Abstract

The Askaryan Radio Array (ARA) is a five-station, in-ice radio detector located at the South Pole searching for particle cascades from cosmogenic and astrophysical neutrinos with $\geq10^{17}$ eV of energy. Cascades in this energy regime emit radio-wavelength Askaryan radiation that can be observed by one or more ARA stations. With the recent KM3Net observation of an approximately $220$ PeV neutrino, there is renewed, urgent interest in further unlocking the ultra-high energy neutrino sky. We present updated calculations of ARA's array-wide effective volume, sensitivity, and expected event rates for ultra-high energy neutrino-induced cascades. Notably, results now account for the contributions of secondary particles from neutrino interactions (such as muon tracks) and multi-station detections within a detailed detector simulation framework. Previous work has shown these secondary interactions and multi-station coincidences compose 25\% and 8\% of the detector's effective area, respectively. We intend to extend these results towards a novel analysis that estimates the degree to which secondary cascades and multi-station observations are detectable in a real neutrino search. This will inform future UHE neutrino searches as it will characterize the feasibility of detecting such events.