A. Aab, Universität Siegen
P. Abreu, Instituto Superior Técnico
M. Aglietta, Istituto Nazionale Di Astrofisica, Rome
E. J. Ahn, Fermi National Accelerator Laboratory
I. Al Samarai, Laboratoire de Physique Nucléaire et de Hautes Energies
I. F.M. Albuquerque, Universidade de São Paulo
I. Allekotte, Instituto Balseiro
J. D. Allen, New York University
P. Allison, The Ohio State University
A. Almela, Centro Atomico Constituyentes
J. Alvarez Castillo, Universidad Nacional Autónoma de México
J. Alvarez-Muñiz, Universidad de Santiago de Compostela
M. Ambrosio, Istituto Nazionale di Fisica Nucleare, Sezione di Napoli
G. A. Anastasi, Istituto Nazionale di Fisica Nucleare - INFN
L. Anchordoqui, Lehman College
B. Andrada, Centro Atomico Constituyentes
S. Andringa, Instituto Superior Técnico
C. Aramo, Istituto Nazionale di Fisica Nucleare, Sezione di Napoli
F. Arqueros, Universidad Complutense de Madrid
N. Arsene, Universitatea din Bucuresti
H. Asorey, Instituto Balseiro
P. Assis, Instituto Superior Técnico
J. Aublin, Laboratoire de Physique Nucléaire et de Hautes Energies
G. Avila, Pierre Auger Observatory
A. M. Badescu, University Politehnica of Bucharest
C. Baus, Karlsruher Institut für Technologie
J. J. Beatty, The Ohio State University
K. H. Becker, Bergische Universität Wuppertal
J. A. Bellido, The University of Adelaide
C. Berat, Universite Grenoble Alpes
M. E. Bertaina, Istituto Nazionale di Fisica Nucleare, Sezione di Torino
X. Bertou, Instituto Balseiro
P. L. Biermann, Max Planck Institute for Radio Astronomy

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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 (ECM=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.

Publication Source (Journal or Book title)

Physical Review Letters