Askaryan Radio Array: searching for the highest energy neutrinos

TL;DR

The Askaryan Radio Array (ARA) is a pioneering in-ice detector at the South Pole designed to search for ultra-high energy neutrinos, aiming to set the most sensitive flux limits below 1000 EeV.

Contribution

This paper provides an overview of the ARA detector, its detection methods, and reports on its current status and achievements in ultra-high energy neutrino searches.

Findings

ARA has accumulated over 27 station years of data.

It is expected to produce the most sensitive neutrino flux limits below 1000 EeV.

The array has demonstrated effective detection of neutrino-induced Askaryan radiation.

Abstract

Searches for ultra-high energy ($E_\nu \geq 10$ PeV) cosmogenic and astrophysical neutrinos (UHENs) have been conducted by several experiments over the last two decades. The Askaryan Radio Array (ARA), located near the geographical South Pole, was one of the first two experiments that used radio antennas sensitive to orthogonal polarizations for detection of neutrino-induced Askaryan radiation. ARA comprises five independent autonomous stations, with an additional low threshold phased array merged with station 5, which were deployed at a depth of 100-200 m over the period 2012-2018, corresponding to a total livetime of more than 27 station years. In this article, we present a brief overview of the detector, its detection technique, and discuss a few of its major achievements with a focus on the current status of the array-wide UHEN search. We expect to produce the most sensitive results on the neutrino flux by any existing in-ice neutrino experiment below 1000 EeV energy.