First-principle calculation of birefringence effects for in-ice radio detection of neutrinos. (arXiv:2205.06169v1 [astro-ph.IM])
<a href="http://arxiv.org/find/astro-ph/1/au:+Heyer_N/0/1/0/all/0/1">Nils Heyer</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Glaser_C/0/1/0/all/0/1">Christian Glaser</a>
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 flashes. Here, we study the effect of birefringence in ice, which splits
up the radio pulse into two orthogonal polarization components with slightly
different propagation speeds. This provides useful signatures to determine the
neutrino energy and is potentially important to determine the neutrino
direction to degree precision. We calculated the effect of birefringence from
first principles where the only free parameter is the dielectric tensor as a
function of position. Our code, for the first time, can propagate full RF
waveforms, taking interference due to changing polarization eigenvectors during
propagation into account. The model is available open-source through the
NuRadioMC framework. We compare our results to in-situ calibration data from
the ARA and ARIANNA experiments and find good agreement for the available time
delay measurements, improving the predictions significantly compared to
previous studies. Finally, the implications and opportunities for neutrino
detection are discussed.
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 flashes. Here, we study the effect of birefringence in ice, which splits
up the radio pulse into two orthogonal polarization components with slightly
different propagation speeds. This provides useful signatures to determine the
neutrino energy and is potentially important to determine the neutrino
direction to degree precision. We calculated the effect of birefringence from
first principles where the only free parameter is the dielectric tensor as a
function of position. Our code, for the first time, can propagate full RF
waveforms, taking interference due to changing polarization eigenvectors during
propagation into account. The model is available open-source through the
NuRadioMC framework. We compare our results to in-situ calibration data from
the ARA and ARIANNA experiments and find good agreement for the available time
delay measurements, improving the predictions significantly compared to
previous studies. Finally, the implications and opportunities for neutrino
detection are discussed.
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