Search for Extremely-High-Energy Neutrinos and First Constraints on the Ultrahigh-Energy Cosmic-Ray Proton Fraction with IceCube
Journal article, 2025
We present a search for the diffuse extremely-high-energy neutrino flux using 12.6 years of IceCube data. The nonobservation of neutrinos with energies well above 10 PeV constrains the all-flavor neutrino flux at 1018 eV to a level of E2φνe+νμ+ντ≃10-8 GeV cm-2 s-1 sr-1, the most stringent limit to date. Using these data, we constrain the proton fraction of ultrahigh-energy cosmic rays (UHECRs) above ≃30 EeV to be ≲70% (at 90% CL) if the cosmological evolution of the sources is comparable to or stronger than the star formation rate. This is the first result to disfavor the "proton-only"hypothesis for UHECR in this evolution regime using neutrino data. This result complements direct air-shower measurements by being insensitive to uncertainties associated with hadronic interaction models. We also evaluate the tension between IceCube-s nonobservation and the ∼200 PeV KM3NeT neutrino candidate (KM3-230213A), finding it to be ∼2.9σ based on a joint-livetime fit between neutrino datasets.
Author
R. Abbasi
Loyola University of Chicago
M. Ackermann
Deutsches Elektronen-Synchrotron (DESY)
J. Adams
University of Canterbury
S. K. Agarwalla
Institute of Physics Bhubaneswar
Wisconsin IceCube Particle Astrophysics Center
J.A. Aguilar
Université libre de Bruxelles (ULB)
M. Ahlers
Niels Bohr Institute
J. M. Alameddine
Technische Universität Dortmund
N.M. Amin
University of Delaware
K. Andeen
Marquette University
C. Argüelles
Harvard University
Y. Ashida
University of Utah
S. Athanasiadou
Deutsches Elektronen-Synchrotron (DESY)
S. N. Axani
University of Delaware
R. Babu
Michigan State University
X. Bai
South Dakota School of Mines & Technology
A. V. Balagopal
Wisconsin IceCube Particle Astrophysics Center
M. Baricevic
Wisconsin IceCube Particle Astrophysics Center
S. W. Barwick
University of California
S. Bash
Technical University of Munich
V. Basu
Wisconsin IceCube Particle Astrophysics Center
R. Bay
University of California
J.J. Beatty
Ohio State University
Julia Tjus
Ruhr-Universität Bochum
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
J. Beise
Uppsala University
C. Bellenghi
Technical University of Munich
S. Benzvi
University of Rochester
D. Berley
University of Maryland
E. Bernardini
University of Padua
D. Z. Besson
University of Kansas
E. Blaufuss
University of Maryland
L. Bloom
University of Alabama
S. Blot
Deutsches Elektronen-Synchrotron (DESY)
F. Bontempo
Karlsruhe Institute of Technology (KIT)
J.Y. Book Motzkin
Harvard University
C. Boscolo Meneguolo
University of Padua
S. Böser
Johannes Gutenberg University Mainz
O. Botner
Uppsala University
J. Böttcher
RWTH Aachen University
J. Braun
Wisconsin IceCube Particle Astrophysics Center
B. Brinson
Georgia Institute of Technology
Z. Brisson-Tsavoussis
Queen's University
J. Brostean-Kaiser
Deutsches Elektronen-Synchrotron (DESY)
L. Brusa
RWTH Aachen University
R. T. Burley
University of Adelaide
D. Butterfield
Wisconsin IceCube Particle Astrophysics Center
M.A. Campana
Drexel University
I. Caracas
Johannes Gutenberg University Mainz
K. Carloni
Harvard University
J. Carpio
University of Nevada, Las Vegas
S. Chattopadhyay
Institute of Physics Bhubaneswar
Wisconsin IceCube Particle Astrophysics Center
N. Chau
Université libre de Bruxelles (ULB)
Z. Chen
Stony Brook University
D. Chirkin
Wisconsin IceCube Particle Astrophysics Center
S. Choi
Sungkyunkwan University
B.A. Clark
University of Maryland
A. Coleman
Uppsala University
P. Coleman
RWTH Aachen University
G.H. Collin
Massachusetts Institute of Technology (MIT)
A. Connolly
Ohio State University
J.M. Conrad
Massachusetts Institute of Technology (MIT)
R. Corley
University of Utah
D. F. Cowen
Eberly College of Science
Pennsylvania State University
C. De Clercq
Vrije Universiteit Brussel (VUB)
J.J. Delaunay
University of Alabama
D. Delgado
Harvard University
S. Deng
RWTH Aachen University
A. Desai
Wisconsin IceCube Particle Astrophysics Center
P. Desiati
Wisconsin IceCube Particle Astrophysics Center
K. D. De Vries
Vrije Universiteit Brussel (VUB)
G. De Wasseige
Universite catholique de Louvain
T. Deyoung
Michigan State University
A. Diaz
Massachusetts Institute of Technology (MIT)
J. C. Díaz-Vélez
Wisconsin IceCube Particle Astrophysics Center
P. Dierichs
RWTH Aachen University
M. Dittmer
University of Münster
A. Domi
University of Erlangen-Nuremberg (FAU)
L. Draper
University of Utah
H. Dujmovic
Wisconsin IceCube Particle Astrophysics Center
D. Durnford
University of Alberta
K. Dutta
Johannes Gutenberg University Mainz
M. A. Duvernois
Wisconsin IceCube Particle Astrophysics Center
T. Ehrhardt
Johannes Gutenberg University Mainz
L. Eidenschink
Technical University of Munich
A. Eimer
University of Erlangen-Nuremberg (FAU)
P. Eller
Technical University of Munich
E. Ellinger
Bergische Universität Wuppertal
S. El Mentawi
RWTH Aachen University
D. Elsaesser
Technische Universität Dortmund
R. Engel
Karlsruhe Institute of Technology (KIT)
H. Erpenbeck
Wisconsin IceCube Particle Astrophysics Center
W. Esmail
University of Münster
J. Evans
University of Maryland
P.A. Evenson
University of Delaware
K.L. Fan
University of Maryland
K. Fang
Wisconsin IceCube Particle Astrophysics Center
K. Farrag
Chiba University
A. R. Fazely
Southern University and A&M College
A. Fedynitch
Academia Sinica
N. Feigl
Humboldt University of Berlin
S. Fiedlschuster
University of Erlangen-Nuremberg (FAU)
Physical Review Letters
0031-9007 (ISSN) 1079-7114 (eISSN)
Vol. 135 3 031001Subject Categories (SSIF 2025)
Astronomy, Astrophysics, and Cosmology
Subatomic Physics
DOI
10.1103/PhysRevLett.135.031001