The interplay between the electromagnetic and the muonic longitudinal profile at production

TL;DR

This paper investigates the relationship between electromagnetic and muonic longitudinal profiles in particle showers, revealing universal features and model-independent variables that can help determine primary cosmic ray composition.

Contribution

It introduces a phenomenological analysis of both profiles across various conditions, highlighting their potential to disentangle primary mass composition from hadronic interaction models.

Findings

Muonic profile shows universal features similar to electromagnetic profile.

Both profiles provide primary mass composition variables independent of hadronic models.

Combining profiles helps break degeneracy between primary mass and hadronic physics.

Abstract

The electromagnetic and the muonic longitudinal profile at production enclosure important information about the primary particle and the hadronic interactions that rule the shower development. In fact, these two profiles provide two different insights of the shower: the electromagnetic component gives a measurement of the energy and the strength of the neutral pion channel; while the muonic profile, being intimately related with the charged mesons decays, can be used as a direct probe for the high energy hadronic interactions. In this work we explore the interplay between the electromagnetic and muonic profiles, by analysing their phenomenologic behaviour for different primary masses and energies, zenith angles, and also different high energy hadronic interaction models. We have found that the muonic longitudinal profile at production displays universal features similar to what is known for the electromagnetic one. Moreover, we show that both profiles have new primary mass composition variables which are fairly independent of the high energy hadronic interaction model. Finally we discuss how the information in the electromagnetic and the muonic longitudinal profile can be combined to break the degeneracy between the primary mass composition and the high energy hadronic physics.