Benefits of Looking for Coincident Events, Taus, and Muons with the Askaryan Radio Array

TL;DR

This paper demonstrates that including secondary interactions like taus and muons in simulations significantly enhances the detection capabilities of the Askaryan Radio Array for ultra-high energy neutrinos, with a notable 30% increase in effective area.

Contribution

It introduces comprehensive simulation results that incorporate secondary interactions, improving the estimation of neutrino detection potential for the ARA and similar observatories.

Findings

30% increase in ARA's effective area at 10^{19} eV when including taus and muons

Significant enhancement in detection estimates by accounting for secondary cascade interactions

Visualizations of complex event topologies for ultra-high energy neutrino interactions

Abstract

Ultra-High Energy (UHE) neutrinos over $10^{16}$ eV have yet to be observed but the Askaryan Radio Array (ARA) is one in-ice neutrino observatory attempting to make this discovery. In anticipation of a thorough full-observatory and full-livetime neutrino search, we estimate how many neutrino events can be detected accounting for secondary interactions, which are typically ignored in UHE neutrino simulations. Using the NuLeptonSim and PyREx simulation frameworks, we calculate the abundance and usefulness of cascades viewed by multiple ARA stations and observations made of taus, muons, and neutrinos generated during and after initial neutrino cascades. Analyses that include these scenarios benefit from a considerable increase in effective area at key ARA neutrino energies, one example being a 30% increase in ARA's effective area when simulating taus and muons produced in $10^{19}$ eV neutrino interactions. These analysis techniques could be utilized by other in-ice radio neutrino observatories, as has been explored by NuRadioMC developers. Our contribution showcases full simulation results of neutrinos with energies $3\times10^{17}$ - $10^{21}$ eV and visualizations of interesting triggered event topologies.