Speaker
Description
The Askaryan Radio Array (ARA) is a radio neutrino detector designed primarily to detect neutrinos with energies above 10 PeV. In addition to neutrinos, ARA is also sensitive to radio emission from cosmic-ray(CR)–induced air showers. Detection of these emissions can support detector calibration, improve the detection capabilities of the detector, and help model CRs as a background for neutrino searches. The detector currently consists of five autonomous stations, including one phased-array station. Each station contains 16 radio antennas deployed at depths of up to 200 m in the Antarctic ice.
ARA Station 2 (A2) recorded a double-pulse event that passed all background-rejection criteria used in a neutrino search analysis. This event is hypothesized to originate from a CR-induced air shower, where the first pulse is produced by in-air geomagnetic emission and the second pulse arises from in-ice Askaryan emission generated by a downward-propagating CR-induced air shower.
We present a Monte Carlo simulation study of the expected CR event topology based on a fitted model. The results show close agreement between simulations and data in terms of the time delay between the two pulses, the reconstructed arrival directions of the signals, and their polarization characteristics. These results support the CR interpretation of the event and demonstrate the capability of ARA to detect such rare signatures.