Deep-learning-based reconstruction of the neutrino direction and energy for in-ice radio detectors

TL;DR

This paper demonstrates that deep neural networks can accurately reconstruct the energy and direction of ultra-high-energy neutrinos using in-ice radio detector data, achieving resolutions suitable for scientific goals.

Contribution

It introduces a novel end-to-end deep learning approach for neutrino reconstruction, including for complex electron neutrino interactions, on simulated in-ice radio detection data.

Findings

Energy resolution with a standard deviation of about a factor of two.

Angular resolution around 1 degree for some events, with a 68% quantile of 4-5 degrees.

Effective modeling of complex correlations in radio detector signals.

Abstract

Ultra-high-energy (UHE) neutrinos ($>10^{16}$ eV) can be measured cost-effectively using in-ice radio detection, which has been explored successfully in pilot arrays. A large radio detector is currently being constructed in Greenland with the potential to measure the first UHE neutrino, and an order-of-magnitude more sensitive detector is being planned with IceCube-Gen2. For such shallow radio detector stations, we present an end-to-end reconstruction of the neutrino energy and direction using deep neural networks (DNNs) developed and tested on simulated data. The DNN determines the energy with a standard deviation of a factor of two around the true energy ($\sigma \approx$ 0.3 in $\log_{10}(E)$), which meets the science requirements of UHE neutrino detectors. For the first time, we are able to predict the neutrino direction precisely for all event topologies including the complicated electron neutrino charged-current ($\nu_e$-CC) interactions. The obtained angular resolution shows a narrow peak at $\mathcal{O}$($1^\circ)$ with extended tails that push the 68\% quantile for non-$\nu_e$-CC (resp. $\nu_e$-CC interactions) to $4^\circ (5^\circ)$. This highlights the advantages of DNNs for modeling the complex correlations in radio detector data, thereby enabling measurement of neutrino energy and direction.