A Sterile Neutrino Origin for the Upward Directed Cosmic Ray Showers Detected by ANITA

TL;DR

This paper proposes that the upward-directed cosmic ray showers detected by ANITA could originate from sterile neutrinos, offering a novel explanation for events that are incompatible with Standard Model particles at EeV energies.

Contribution

It introduces a sterile neutrino interpretation for ANITA's observed events and compares the sensitivity of various experiments to this hypothesis.

Findings

ANITA has unique sensitivity to upward cascades from sterile neutrinos.

The transient acceptance of ANITA for these events is comparable to IceCube.

Sterile neutrinos could explain the anomalous upward cosmic ray showers.

Abstract

The ANITA balloon experiment has recently observed several ~EeV cascade events at an angle below the horizon that renders any Standard Model (SM) interpretation unlikely as the Earth is significantly opaque to all SM particles at such energies. In this paper, we study a sterile neutrino interpretation of these events, calculating the angular acceptance of cascades and the relative sensitivities of several experiments to a cascade initiated by an EeV sterile neutrino. We find that ANITA is uniquely sensitive to this type of upward directed cascade signal over a wide portion of the sky and from the direction of the two observed events has a transient acceptance roughly equivalent to that of the IceCube experiment.