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arXiv · 2602.14720

Bounds on Lorentz invariance violation from muon fluctuations at the Pierre Auger Observatory

The Pierre Auger Collaboration·A. Abdul Halim·P. Abreu·M. Aglietta·I. Allekotte·K. Almeida Cheminant·R. Aloisio·J. Alvarez-Muñiz·A. Ambrosone·J. Ammerman Yebra·L. Anchordoqui·B. Andrada·L. Andrade Dourado·L. Apollonio·C. Aramo·E. Arnone·J. C. Arteaga Velázquez·P. Assis·G. Avila·E. Avocone·A. Bakalova·Y. Balibrea·A. Baluta·F. Barbato·A. Bartz Mocellin·J. P. Behler·C. Berat·M. E. Bertaina·M. Bianciotto·P. L. Biermann·V. Binet·K. Bismark·T. Bister·J. Biteau·J. Blazek·J. Blümer·M. Boháčová·D. Boncioli·C. Bonifazi·N. Borodai·J. Brack·P. G. Brichetto Orquera·A. Bueno·S. Buitink·M. Büsken·A. Bwembya·K. S. Caballero-Mora·S. Cabana-Freire·L. Caccianiga·J. Caraça-Valente·R. Caruso·A. Castellina·F. Catalani·G. Cataldi·L. Cazon·M. Cerda·B. Čermáková·A. Cermenati·K. Cerny·J. A. Chinellato·J. Chudoba·L. Chytka·R. W. Clay·A. C. Cobos Cerutti·R. Colalillo·R. Conceição·G. Consolati·M. Conte·F. Convenga·D. Correia dos Santos·P. J. Costa·C. E. Covault·M. Cristinziani·C. S. Cruz Sanchez·S. Dasso·K. Daumiller·B. R. Dawson·R. M. de Almeida·E. -T. de Boone·B. de Errico·J. de Jesús·S. J. de Jong·J. R. T. de Mello Neto·I. De Mitri·D. de Oliveira Franco·F. de Palma·V. de Souza·E. De Vito·A. Del Popolo·O. Deligny·N. Denner·K. Denner Syrokvas·L. Deval·A. di Matteo·C. Dobrigkeit·J. C. D'Olivo·L. M. Domingues Mendes·Y. Dominguez Ballesteros·Q. Dorosti·R. C. dos Anjos
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Abstract

Quantum gravity theories often modify spacetime symmetries. In particular, Lorentz invariance may be violated when approaching the Planck scale. Although the scales at which interactions occur in extensive air showers induced by ultra-high-energy cosmic rays in the atmosphere are many orders of magnitude below the Planck scale, these violations might still be observable. In this work, the fluctuations in the number of muons in the extensive air showers measured at the Pierre Auger Observatory are exploited, for the first time, to constrain Lorentz invariance violations. The bounds derived in the hadronic sector are the strongest ever obtained, and do not rely on assumptions about the mass composition of ultra-high-energy cosmic rays. The fluctuations in the number of muons constitute a new and powerful observable to further explore Lorentz invariance in a region of the parameter space not accessible to other observables.

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The Pierre Auger Collaboration, A. Abdul Halim, P. Abreu, M. Aglietta, I. Allekotte, K. Almeida Cheminant, R. Aloisio, J. Alvarez-Muñiz, A. Ambrosone, J. Ammerman Yebra, L. Anchordoqui, B. Andrada, L. Andrade Dourado, L. Apollonio, C. Aramo, E. Arnone, J. C. Arteaga Velázquez, P. Assis, G. Avila, E. Avocone, A. Bakalova, Y. Balibrea, A. Baluta, F. Barbato, A. Bartz Mocellin, J. P. Behler, C. Berat, M. E. Bertaina, M. Bianciotto, P. L. Biermann, V. Binet, K. Bismark, T. Bister, J. Biteau, J. Blazek, J. Blümer, M. Boháčová, D. Boncioli, C. Bonifazi, N. Borodai, J. Brack, P. G. Brichetto Orquera, A. Bueno, S. Buitink, M. Büsken, A. Bwembya, K. S. Caballero-Mora, S. Cabana-Freire, L. Caccianiga, J. Caraça-Valente, R. Caruso, A. Castellina, F. Catalani, G. Cataldi, L. Cazon, M. Cerda, B. Čermáková, A. Cermenati, K. Cerny, J. A. Chinellato, J. Chudoba, L. Chytka, R. W. Clay, A. C. Cobos Cerutti, R. Colalillo, R. Conceição, G. Consolati, M. Conte, F. Convenga, D. Correia dos Santos, P. J. Costa, C. E. Covault, M. Cristinziani, C. S. Cruz Sanchez, S. Dasso, K. Daumiller, B. R. Dawson, R. M. de Almeida, E. -T. de Boone, B. de Errico, J. de Jesús, S. J. de Jong, J. R. T. de Mello Neto, I. De Mitri, D. de Oliveira Franco, F. de Palma, V. de Souza, E. De Vito, A. Del Popolo, O. Deligny, N. Denner, K. Denner Syrokvas, L. Deval, A. di Matteo, C. Dobrigkeit, J. C. D'Olivo, L. M. Domingues Mendes, Y. Dominguez Ballesteros, Q. Dorosti, R. C. dos Anjos. 2026-02-16. Bounds on Lorentz invariance violation from muon fluctuations at the Pierre Auger Observatory. https://arxiv.org/abs/2602.14720

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