IceCube and the origin of ANITA-IV events

TL;DR

This paper investigates the mysterious upgoing ultra-high-energy events detected by ANITA, analyzing their compatibility with IceCube data and exploring models involving long-lived particles and specific cross sections, emphasizing the importance of combined observatory efforts.

Contribution

It introduces a generic parametrization to assess the compatibility of ANITA and IceCube observations within Standard Model and Beyond Standard Model scenarios, providing constraints on particle properties and proposing testable hypotheses.

Findings

ANITA's angular distribution constrains particle properties

A specific range of particle lifetime and cross section can explain the data

Future IceCube data can test the proposed scenario

Abstract

Recently, the ANITA collaboration announced the detection of new, unsettling upgoing Ultra-High-Energy (UHE) events. Understanding their origin is pressing to ensure success of the incoming UHE neutrino program. In this work, we study their internal consistency and the implications of the lack of similar events in IceCube. We introduce a generic, simple parametrization to study the compatibility between these two observatories in Standard Model-like and Beyond Standard Model scenarios: an incoming flux of particles that interact with Earth nucleons with cross section $\sigma$, producing particle showers along with long-lived particles that decay with lifetime $\tau$ and generate a shower that explains ANITA observations. We find that the ANITA angular distribution imposes significant constraints, and when including null observations from IceCube only $\tau \sim 10^{-3}$ - $10^{-2} \,\mathrm{s}$ and $\sigma \sim 10^{-33}$ - $10^{-32}\,\mathrm{cm^2}$ can explain the data. This hypothesis is testable with future IceCube data. Finally, we discuss a specific model that can realize this scenario. Our analysis highlights the importance of simultaneous observations by high-energy optical neutrino telescopes and new UHE radio detectors to uncover cosmogenic neutrinos or discover new physics.