Targeting 100-PeV tau neutrino detection with an array of phased and high-gain reconstruction antennas

TL;DR

This paper proposes a hybrid radio detection array combining phased arrays and high-gain outriggers to improve 100-PeV tau neutrino detection efficiency, reducing the number of antennas needed.

Contribution

It introduces a novel combined array design that leverages phased arrays and outriggers, enhancing sensitivity while minimizing hardware requirements.

Findings

Enhanced sensitivity at 100 PeV compared to previous designs

Fewer antennas required for effective detection

Potential for optimized antenna design to further improve performance

Abstract

Neutrinos at ultrahigh energies can originate both from interactions of cosmic rays at their acceleration sites and through cosmic-ray interactions as they propagate through the universe. These neutrinos are expected to have a low flux which drives the need for instruments with large effective areas. Radio observations of the inclined air showers induced by tau neutrino interactions in rock can achieve this, because radio waves can propagate essentially unattenuated through the hundreds of kilometers of atmosphere. Proposed arrays for radio detection of tau neutrinos focus on either arrays of inexpensive receivers distributed over a large area, the GRAND concept, or compact phased arrays on elevated mountains, the BEACON concept, to build up a large detector area with a low trigger threshold. We present a concept that combines the advantages of these two approaches with a trigger driven by phased arrays at a moderate altitude (1 km) and sparse, high-gain outrigger receivers for reconstruction and background rejection. We show that this design has enhanced sensitivity at 100 PeV over the two prior designs with fewer required antennas and discuss the need for optimized antenna designs.