Measurement of the proton-air cross-section at sqrt(s) = 57 TeV with the Pierre Auger Observatory

TL;DR

This paper measures the proton-air cross-section at 57 TeV using cosmic ray data from the Pierre Auger Observatory, providing insights into high-energy particle interactions beyond accelerator capabilities.

Contribution

It presents the first unbiased measurement of the proton-air cross-section at 57 TeV using fluorescence detector data, including systematic uncertainty analysis and comparison with accelerator data.

Findings

Proton-air cross-section at 57 TeV is approximately 505 mb.

Systematic uncertainties are dominated by primary mass composition assumptions.

Inelastic and total proton-proton cross-sections are derived using an extended Glauber model.

Abstract

Using measured events from the fluorescence detector of the Pierre Auger Observatory, an unbiased distribution of the atmospheric slant depths where showers reach their maxima has been obtained. Analyzing the tail of this distribution the proton-air cross-section for particle production at center-of-mass energies per nucleon of 57 TeV is determined to be [505$\pm$22(stat)+28$-$36(syst)] mb. Systematic uncertainties in the analysis arise from the limited knowledge of the primary mass composition, the need to use shower simulations and the selection of events. For the purpose of making comparisons with accelerator data we also calculate the inelastic and total proton-proton cross-sections using an extended Glauber model.