High energy cosmic ray interactions and UHECR composition problem

Sergey Ostapchenko,I Lhenry-Yvon,J Biteau,O Deligny,P Ghia

doi:10.1051/epjconf/201921002001

Abstract

The differences between contemporary Monte Carlo generators of high energy hadronic interactions are discussed and their impact on the interpretation of experimental data on ultra-high energy cosmic rays (UHECRs) is studied. Key directions for further model improvements are outlined. The prospect for a coherent interpretation of the data in terms of the UHECR composition is investigated.

Highlights

Among the most challenging problems of the high energy cosmic ray research is the enigma of ultra-high energy cosmic rays (UHECRs)
Because of the very low UHECR flux, one has to rely on indirect detection techniques: measuring the properties of nuclear-electromagnetic cascades, so-called extensive air showers (EAS), initiated by interactions of the primary cosmic ray (CR) particles in the upper atmosphere [1]
A substantial progress in the latter direction has been achieved with the development of contemporary Monte Carlo (MC) tools for air shower simulations, like the CORSIKA [2], AIRES [3], SENECA [4], and CONEX [5] programs

Summary

Introduction

Among the most challenging problems of the high energy cosmic ray research is the enigma of ultra-high energy cosmic rays (UHECRs). One of the key ingredients of those numerical codes are MC models of high energy collisions of hadrons and nuclei, which describe interactions of both primary CRs and of the produced secondary hadrons with nuclei of the air. Since such collisions generally involve nonperturbative physics, no first principle description can be employed for them and the corresponding models are largely phenomenological ones. Further progress in the understanding of ultra-high energy cosmic rays is closely linked to accelerator studies of high energy collisions of hadrons and nuclei, which are required both for calibrating parameters of such hadronic interaction models and, more importantly, for discriminating between the respective theoretical approaches

Impact of LHC data and further progress

Composition of UHECRs: coherent interpretation of experimental data?

50 Fe-induced EAS no breakup

Outlook