{
  "abstract": "We investigate the sensitivity of the Pierre Auger Observatory to sterile neutrinos with masses in the MeV-to-100 MeV range. To this end, we consider a minimal $3+1$ framework in which a single sterile state mixes mainly with the $ν_τ$ flavor through an active--sterile mixing angle $θ_N$ to produce a mass eigenstate $N_1$. At ultrahigh energies, $N_1$ neutrinos can traverse substantial chord lengths through the Earth and interact through their active component, producing $τ$ leptons that may emerge near the surface and decay in the atmosphere, thereby generating detectable air showers. We compute the corresponding exposures with a detailed Monte Carlo simulation of neutrino propagation, interactions, $τ$ energy losses and decay, and derive upper limits at $90\\%$ confidence level on an isotropic diffuse flux of $N_1$ neutrinos. For an $E^{-2}$ spectrum, we obtain $E^2Φ_N\\leq 2\\times10^{-9}\\sin^{-2}θ_N\\,\\mathrm{GeV\\,cm^{-2}\\,sr^{-1}\\,s^{-1}}$ over $0.3$--$200$ EeV for $\\sin^2θ_N\\lesssim10^{-1}$. We further consider $N_1$ neutrinos arising from the decay of a superheavy dark-matter particle. For a benchmark dark-matter mass of $10^{13}$ GeV, we derive constraints on the active--sterile mixing angle and dark-matter lifetime for sterile-neutrino masses of $10$ and $100$ MeV. These results illustrate the potential of the Observatory to probe long-lived weakly interacting particles.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2611.06284",
  "author_total": 354,
  "authors": [
    {
      "name": "The Pierre Auger Collaboration"
    },
    {
      "name": "A. Abdul Halim"
    },
    {
      "name": "P. Abreu"
    },
    {
      "name": "M. Aglietta"
    },
    {
      "name": "M. Ahmed"
    },
    {
      "name": "I. Allekotte"
    },
    {
      "name": "K. Almeida Cheminant"
    },
    {
      "name": "R. Aloisio"
    },
    {
      "name": "J. Alvarez-Muñiz"
    },
    {
      "name": "A. Ambrosone"
    },
    {
      "name": "J. Ammerman Yebra"
    },
    {
      "name": "L. Anchordoqui"
    },
    {
      "name": "B. Andrada"
    },
    {
      "name": "L. Andrade Dourado"
    },
    {
      "name": "L. Apollonio"
    },
    {
      "name": "C. Aramo"
    },
    {
      "name": "J. C. Arteaga Velázquez"
    },
    {
      "name": "P. Assis"
    },
    {
      "name": "G. Avila"
    },
    {
      "name": "E. Avocone"
    },
    {
      "name": "A. Bakalova"
    },
    {
      "name": "Y. Balibrea"
    },
    {
      "name": "A. Baluta"
    },
    {
      "name": "F. Barbato"
    },
    {
      "name": "A. Bartz Mocellin"
    },
    {
      "name": "O. Batalla Cruz"
    },
    {
      "name": "J. P. Behler"
    },
    {
      "name": "C. Berat"
    },
    {
      "name": "M. E. Bertaina"
    },
    {
      "name": "M. Bianciotto"
    },
    {
      "name": "P. L. Biermann"
    },
    {
      "name": "V. Binet"
    },
    {
      "name": "K. Bismark"
    },
    {
      "name": "T. Bister"
    },
    {
      "name": "J. Biteau"
    },
    {
      "name": "J. Blazek"
    },
    {
      "name": "J. Blümer"
    },
    {
      "name": "M. Boháčová"
    },
    {
      "name": "D. Boncioli"
    },
    {
      "name": "C. Bonifazi"
    },
    {
      "name": "P. Boril"
    },
    {
      "name": "N. Borodai"
    },
    {
      "name": "J. Brack"
    },
    {
      "name": "P. G. Brichetto Orquera"
    },
    {
      "name": "S. Buitink"
    },
    {
      "name": "A. Bwembya"
    },
    {
      "name": "T. R. Caba Pineda"
    },
    {
      "name": "K. S. Caballero-Mora"
    },
    {
      "name": "S. Cabana-Freire"
    },
    {
      "name": "L. Caccianiga"
    },
    {
      "name": "J. Caraça-Valente"
    },
    {
      "name": "R. Caruso"
    },
    {
      "name": "A. Castellina"
    },
    {
      "name": "F. Catalani"
    },
    {
      "name": "G. Cataldi"
    },
    {
      "name": "L. Cazon"
    },
    {
      "name": "M. Cerda"
    },
    {
      "name": "B. Čermáková"
    },
    {
      "name": "A. Cermenati"
    },
    {
      "name": "K. Cerny"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/6kbn59gmb6pad.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2611.06284",
  "fulltext_url": null,
  "id": "6kbn59gmb6pad",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2611.06284",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "astro-ph.HE"
    ],
    [
      "arxiv",
      "hep-ph"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2611.06284",
  "pmcid": null,
  "pmid": null,
  "published": "2026-11-04",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/6kbn59gmb6pad.ris",
  "sources": [
    {
      "first_seen": "2026-11-05T15:20:56Z",
      "native_id": "2611.06284",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2611.06284"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.HE",
      "subfield": "high-energy-astrophysics"
    },
    {
      "field": "physics",
      "origin": "arxiv:hep-ph",
      "subfield": "high-energy"
    }
  ],
  "title": "A search for sterile neutrinos at ultrahigh energies at the Pierre Auger Observatory",
  "title_text": "A search for sterile neutrinos at ultrahigh energies at the Pierre Auger Observatory",
  "type": "preprint",
  "updated_at": "2026-11-09T00:20:20Z",
  "url": "https://research.draconitic.com/paper/6kbn59gmb6pad",
  "venue": "arXiv",
  "versions": []
}