Giant Atmospheric Showers Detected by the Yakutsk Extensive Air Shower Array

TL;DR

This paper reports on the detection of two extremely high-energy atmospheric showers with unusual muon content at Yakutsk, challenging existing models of hadron interactions and suggesting potential new physics or exotic primary particles.

Contribution

It presents the observation and analysis of the most powerful EAS events with anomalously high muon fractions, highlighting possible implications for ultra-high energy particle physics.

Findings

Detected two ultra-high energy EAS with energies around 10^{20} eV.

Observed muon fractions exceed current model predictions.

Results suggest potential new physics or exotic primaries at ultra-high energies.

Abstract

The two most powerful extensive air showers (EAS) with energies of about $10^{20}$ eV, registered at the Yakutsk EAS array during the entire observation period of 1974-2024, are considered. Both showers hit the array near the center and triggered all surface detectors and underground muon detectors with a threshold energy of $E_{\mu} = 1.0 \times \cos \theta$ GeV. These events have an abnormally high fraction of muons, which is beyond current model predictions. This may change our understanding of hadron interactions at ultra-high energy, but there is also a possibility that these showers were initiated by some exotic primary particles.