Testing hadronic interactions at ultrahigh energies with air showers measured by the Pierre Auger Observatory

THE PIERRE AUGER COLLABORATION; ANDRADA, B.

PHYSICAL REVIEW LETTERS

AMER PHYSICAL SOC

Lugar: New York; Año: 2016 vol. 117

0031-9007

Ultrahigh energy cosmic ray air showers probe particle physics at energies beyond the reach of accelerators. Here we introduce a new method to test hadronic interaction models without relying on the absolute energy calibration, and apply it to events with primary energy 6?16 EeV (E_CM = 110?170 TeV), whose longitudinal development and lateral distribution were simultaneously measured by the Pierre Auger Observatory. The average hadronic shower is 1.33 +/- 0.16 (1.61 +/- 0.21) times larger than predicted using the leading LHC-tuned models EPOS-LHC (QGSJetII-04), with a corresponding excess of muons.