Extensive Air Showers: from the muonic smoking guns to the hadronic backbone

TL;DR

This paper reviews the complex structure of extensive air showers initiated by ultra-high energy particles, emphasizing the role of muons as key indicators of the hadronic cascade and discussing experimental approaches to analyze them.

Contribution

It provides a comprehensive overview of muon phenomenology in air showers and explores new methods for using muon data to understand hadronic interactions.

Findings

Muons serve as smoking guns for the hadronic cascade.

Muon properties like energy and distribution reveal the shower's history.

Experimental efforts are advancing in muon analysis within air showers.

Abstract

Extensive Air Showers are complex macroscopic objects initiated by single ultra-high energy particles. They are the result of millions of high energy reactions in the atmosphere and can be described as the superposition of hadronic and electromagnetic cascades. The hadronic cascade is the air shower backbone, and it is mainly made of pions. Decays of neutral pions initiate electromagnetic cascades, while the decays of charged pions produce muons which leave the hadronic core and travel many kilometers almost unaffected. Muons are smoking guns of the hadronic cascade: the energy, transverse momentum, spatial distribution and depth of production are key to reconstruct the history of the air shower. In this work, we overview the phenomenology of muons on the air shower and its relation to the hadronic cascade. We briefly review the experimental efforts to analyze muons within air showers and discuss possible paths to use this information.