Pioneering an Array-Wide Search for Ultra-high Energy Neutrinos with the Askaryan Radio Array

The Askaryan Radio Array (ARA) at the South Pole is conducting the first array-wide search for ultra-high energy (UHE) neutrinos using radio detection in glacial ice. Spanning five autonomous stations and nearly thirty station-years of exposure, this analysis unifies ARA's entire dataset within a new end-to-end framework, AraProc, which performs all aspects of waveform processing, event reconstruction, background identification and rejection, and analysis variable computation in a consistent, scalable way. Enhanced detector simulations incorporating data-driven noise, antenna gain models, and multi-station neutrino propagation via NuLeptonSim and AraSim have yielded the most realistic effective-volume calculations yet achieved for ARA. Using a blinded 10% dataset, the optimized pipeline demonstrates order-of-magnitude improvements in thermal and continuous-wave background suppression and achieves the highest projected sensitivity of any in-ice radio experiment above 3 EeV. The forthcoming unblinding of the full dataset will yield the first neutrino candidates ever seen by ARA, and by any in-ice radio experiment. Alternatively, it will establish the most stringent flux limits to date, marking a milestone for next-generation experiments such as RNO-G and IceCube-Gen2 Radio.