Birefringence: Effects and Implications on In-Ice Radio Detection of High-Energy Neutrinos

Abstract: The detection of high-energy neutrinos in the EeV range requires new detection techniques to cope with the small expected flux. The radio detection method, utilizing Askaryan emission, can be used to detect these neutrinos in polar ice. The propagation of the radio pulses has to be modeled carefully to reconstruct the energy, direction, and flavor of the neutrino from the detected radio signals. This thesis outlines the effect of birefringence in ice, which splits up the radio pulse into two orthogonal polarization components with slightly different propagation speeds. The signatures resulting from birefringence can help to reconstruct the energy and direction of the neutrino. In this thesis, the effect of birefringence is derived from first principles where the only free parameter of the model is the dielectric tensor as a function of depth and direction. The introduced model can propagate full RF waveforms which for the first time allows for the accounting of interference due to changing polarization eigenvectors during propagation. The model is available open-source through the NuRadioMC framework. The predictions of the model are compared to in-situ calibration data from the ARA and ARIANNA experiments and the implications for neutrino detection are discussed.