| Summary: | The emerging field of radio based neutrino astronomy holds promise in answering long lasting questions about our universe such as identifying the sources of ultra-high energy (UHE) cosmic rays. This requires a multi-messenger effort in astronomy which is a relatively new collaboration between the various particles/waves used to study space. It is important for radio neutrino astronomers to show that UHE neutrino detection can be made with excellent precision in direction and energy reconstruction for the field to grow from pilot phases into large scale experiments. The Antarctic Ross Ice-shelf Antenna Neutrino Array (ARIANNA) is one such detector with this goal. ARIANNA aims to detect UHE neutrinos via radio (Askaryan) emission from particle showers when a neutrino interacts with ice, which is an efficient method for neutrinos with energies between 10^16 eV and 10^20 eV. The ARIANNA radio detectors are located in Antarctic ice just beneath the surface. Neutrino observation requires that radio pulses propagate to the antennas at the surface with minimum distortion by the ice and firn medium. To reconstruct the direction, a measurement of polarization, radio frequency signal direction, and viewing angle off of the Cerenkov cone, along with ice attenuation and signal trajectories must be made. The energy further requires a modeling of the Askaryan radiation created from the stochastic processes of particle showers in dense media. This results in an irreducible energy resolution, which sets the goal for energy reconstruction techniques. An experimental evaluation of radio signal polarization and direction resolution was completed using the residual hole from the South Pole Ice Core (SPICEcore) Project. Radio pulses were emitted from a transmitter located down to 1.7km below the snow surface. After deconvolving the raw signals for the detector response and attenuation from propagation through the ice, the signal pulses show no significant distortion and agree with a reference measurement of the emitter made in an anechoic chamber. The origin of the transmitted radio pulse was measured with an angular resolution of 0.37 degrees, indicating that the neutrino direction can be determined with good precision if the polarization and viewing angle of the radio-pulse can be well determined. In the present study we obtained a resolution of the polarization vector of 2.7 degrees. Neither measurement show a significant offset relative to expectation. We also report on the results of a simulation study of the ARIANNA neutrino direction and energy resolution. The software tool NuRadioMC, which is rapidly becoming the industry standard, was used to reconstruct the polarization and viewing angle to determine the neutrino direction. Multiple models of Askaryan radiation and detector sites along with a range of neutrino energies were tested. The neutrino space angle resolution was determined to be below 3 degrees, which is governed by the polarization uncertainty of the same scale. The polarization reconstruction from experimental SPICEcore studies showed large systematic errors that results in the 2.7 degrees uncertainty, whereas the per depth resolution is a sub degree statistical error. Therefore it is expected that the polarization resolution, which is the dominant contribution to the neutrino space angle resolution, will be greatly improved in future studies by determining and eliminating systematic effects such as antenna modeling. Neutrino energy resolution is reported at 40% for 10^18 eV neutrinos, which is below the inelasticity limit and therefore ARIANNA is not limited by its detectors ability to reconstruct the energy.
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