A search for sterile neutrinos at ultrahigh energies at the Pierre Auger Observatory
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 ντ flavor through an active--sterile mixing angle θN to produce a mass eigenstate N1. At ultrahigh energies, N1 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 N1 neutrinos. For an E−2 spectrum, we obtain E2ΦN≤ 2×10−9sin−2θN GeV cm−2 sr−1 s−1 over $0.3−−200$ EeV for sin2θN≲10−1. We further consider N1 neutrinos arising from the decay of a superheavy dark-matter particle. For a benchmark dark-matter mass of 1013 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.
Related
- Constraining tau-sterile neutrino mixing with high-energy astrophysical neutrinos
- Search for high-energy neutrinos from Einstein Probe detected Fast X-ray Transients using 14 years of IceCube muon track data
- The First Array-Wide Diffuse Flux Search for UHE Neutrinos with the Askaryan Radio Array
- A Century-Long Archival Search and Analysis of the Rubin Observatory-Discovered Dwarf Planet Candidate 2026 ED138
- Search for Neutrinos from Tidal Disruption Events with IceCube
BibTeX
@misc{collaboration2026search,
title = {{A search for sterile neutrinos at ultrahigh energies at the Pierre Auger Observatory}},
author = {The Pierre Auger Collaboration and A. Abdul Halim and P. Abreu and M. Aglietta and M. Ahmed and I. Allekotte and K. Almeida Cheminant and R. Aloisio and J. Alvarez-Muñiz and A. Ambrosone and J. Ammerman Yebra and L. Anchordoqui and B. Andrada and L. Andrade Dourado and L. Apollonio and C. Aramo and J. C. Arteaga Velázquez and P. Assis and G. Avila and E. Avocone and A. Bakalova and Y. Balibrea and A. Baluta and F. Barbato and A. Bartz Mocellin and O. Batalla Cruz and J. P. Behler and C. Berat and M. E. Bertaina and M. Bianciotto and P. L. Biermann and V. Binet and K. Bismark and T. Bister and J. Biteau and J. Blazek and J. Blümer and M. Boháčová and D. Boncioli and C. Bonifazi and P. Boril and N. Borodai and J. Brack and P. G. Brichetto Orquera and S. Buitink and A. Bwembya and T. R. Caba Pineda and K. S. Caballero-Mora and S. Cabana-Freire and L. Caccianiga and J. Caraça-Valente and R. Caruso and A. Castellina and F. Catalani and G. Cataldi and L. Cazon and M. Cerda and B. Čermáková and A. Cermenati and K. Cerny},
howpublished = {arXiv},
year = {2026},
month = nov,
doi = {10.48550/arxiv.2611.06284},
eprint = {2611.06284},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2611.06284},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - A search for sterile neutrinos at ultrahigh energies at the Pierre Auger Observatory
AU - The Pierre Auger Collaboration
AU - A. Abdul Halim
AU - P. Abreu
AU - M. Aglietta
AU - M. Ahmed
AU - I. Allekotte
AU - K. Almeida Cheminant
AU - R. Aloisio
AU - J. Alvarez-Muñiz
AU - A. Ambrosone
AU - J. Ammerman Yebra
AU - L. Anchordoqui
AU - B. Andrada
AU - L. Andrade Dourado
AU - L. Apollonio
AU - C. Aramo
AU - J. C. Arteaga Velázquez
AU - P. Assis
AU - G. Avila
AU - E. Avocone
AU - A. Bakalova
AU - Y. Balibrea
AU - A. Baluta
AU - F. Barbato
AU - A. Bartz Mocellin
AU - O. Batalla Cruz
AU - J. P. Behler
AU - C. Berat
AU - M. E. Bertaina
AU - M. Bianciotto
AU - P. L. Biermann
AU - V. Binet
AU - K. Bismark
AU - T. Bister
AU - J. Biteau
AU - J. Blazek
AU - J. Blümer
AU - M. Boháčová
AU - D. Boncioli
AU - C. Bonifazi
AU - P. Boril
AU - N. Borodai
AU - J. Brack
AU - P. G. Brichetto Orquera
AU - S. Buitink
AU - A. Bwembya
AU - T. R. Caba Pineda
AU - K. S. Caballero-Mora
AU - S. Cabana-Freire
AU - L. Caccianiga
AU - J. Caraça-Valente
AU - R. Caruso
AU - A. Castellina
AU - F. Catalani
AU - G. Cataldi
AU - L. Cazon
AU - M. Cerda
AU - B. Čermáková
AU - A. Cermenati
AU - K. Cerny
PY - 2026
DA - 2026/11/04
PB - arXiv
DO - 10.48550/arxiv.2611.06284
UR - https://arxiv.org/abs/2611.06284
AB - 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≤ 2×10^−9sin^−2θ_N GeV cm^−2 sr^−1 s^−1 over $0.3−−200$ EeV for sin^2θ_N≲10^−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.
ER -