Eur. Phys. J. Spec. Top.
https://doi.org/10.1140/epjs/s11734-025-01708-7

Review

Askaryan Radio Array: searching for the highest energy neutrinos

¹ Department of Physics and Astronomy, University of Kansas, 66045, Lawrence, KS, USA
² Department of Physics, Center for Cosmology and AstroParticle Physics, The Ohio State University, 43210, Columbus, OH, USA
³ Department of Physics, Chiba University, Chiba, Japan
⁴ Department of Physics, University of Wisconsin-Madison, 53706, Madison, WI, USA
⁵ Department of Physics, Grad. Inst. of Astrophys., Leung Center for Cosmology and Particle Astrophysics, National Taiwan University, Taipei, Taiwan
⁶ Department of Physics, University of Maryland, 20742, College Park, MD, USA
⁷ Department of Physics and Astronomy, University College London, London, UK
⁸ Center for Multi-Messenger Astrophysics, Institute for Gravitation and the Cosmos, Pennsylvania State University, 16802, University Park, PA, USA
⁹ Department of Physics, Pennsylvania State University, 16802, University Park, PA, USA
¹⁰ Department of Astronomy and Astrophysics, Pennsylvania State University, 16802, University Park, PA, USA
¹¹ Vrije Universiteit Brussel, Brussels, Belgium
¹² Department of Physics, Enrico Fermi Institue, Kavli Institute for Cosmological Physics, University of Chicago, 60637, Chicago, IL, USA
¹³ Department of Physics and Astronomy, University of Nebraska, 68588, Lincoln, NE, USA
¹⁴ Department of Physics and Astronomy, Whittier College, 90602, Whittier, CA, USA
¹⁵ Department of Physics, University of Delaware, 19716, Newark, DE, USA
¹⁶ Department of Energy Engineering, National United University, Miaoli, Taiwan
¹⁷ Department of Applied Physics, National Pingtung University, Pingtung City, Pingtung County 900393, Taiwan
¹⁸ Department of Physics and Astronomy, Denison University, 43023, Granville, OH, USA
¹⁹ National Nano Device Laboratories, Hsinchu 300, Taiwan
²⁰ Universite Libre de Bruxelles, Science Faculty CP230, 1050, Brussels, Belgium
²¹ Department of Physics and Astronomy, University of Hawaii, 96822, Manoa, HI, USA
²² Department of Physics and Astronomy, University of Kansas, 66045, Lawrence, KS, USA

^a fulhossain@ku.edu
^b fulhossain@ku.edu

Received: 5 November 2024
Accepted: 20 May 2025
Published online: 17 July 2025

Abstract

Searches for ultra-high energy ($E_{\nu }\ge 10$ 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 to use 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 string 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.