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Estimating the sensitivity of the IceCube Upgrade to probe the interior of the Earth using atmospheric neutrino oscillations
Authors:
The IceCube Collaboration,
R. Abbasi,
M. Ackermann,
J. Adams,
S. K. Agarwalla,
J. A. Aguilar,
M. Ahlers,
J. M. Alameddine,
S. Ali,
N. M. Amin,
K. Andeen,
C. Arg{ü}elles,
S. Athanasiadou,
S. N. Axani,
R. Babu,
X. Bai,
A. Balagopal V.,
S. W. Barwick,
V. Basu,
R. Bay,
J. J. Beatty,
J. Becker Tjus,
P. Behrens,
J. Beise,
C. Bellenghi
, et al. (399 additional authors not shown)
Abstract:
The IceCube Upgrade is a densely instrumented central region of the IceCube Neutrino Observatory, deployed during the 2025-26 polar season. It will reduce the detector's energy threshold and improve overall reconstruction capabilities for multi-GeV atmospheric neutrinos, which in turn enhance their sensitivity to Earth matter effects as they traverse through the deep Earth. In this study, we descr…
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The IceCube Upgrade is a densely instrumented central region of the IceCube Neutrino Observatory, deployed during the 2025-26 polar season. It will reduce the detector's energy threshold and improve overall reconstruction capabilities for multi-GeV atmospheric neutrinos, which in turn enhance their sensitivity to Earth matter effects as they traverse through the deep Earth. In this study, we describe the potential of the IceCube Upgrade to observe Earth matter effects on atmospheric neutrinos and estimate the detector's sensitivity to probe key features of the Preliminary Reference Earth Model by utilizing these observations. We highlight the IceCube Upgrade's capability to estimate the mass of the Earth and verify the non-homogeneous distribution of matter density within the Earth. We also estimate the IceCube Upgrade sensitivity to measure the correlated densities of the Earth layers while incorporating constraints from the mass and moment of inertia of the Earth. Neutrino-based results would be independent and complementary to the seismic and gravitational measurements.
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Submitted 6 August, 2026;
originally announced August 2026.
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High-Energy Neutrino Tomography of the Earth's Interior with IceCube
Authors:
The IceCube Collaboration,
R. Abbasi,
M. Ackermann,
J. Adams,
J. A. Aguilar,
M. Ahlers,
J. M. Alameddine,
S. Ali,
N. M. Amin,
K. Andeen,
C. Argüelles,
S. Athanasiadou,
S. N. Axani,
R. Babu,
X. Bai,
A. Balagopal V.,
S. W. Barwick,
V. Basu,
R. Bay,
J. J. Beatty,
J. Becker Tjus,
P. Behrens,
J. Beise,
C. Bellenghi,
S. Benkel
, et al. (395 additional authors not shown)
Abstract:
The Earth's interior reflects its geological evolution, from accretion to present-day dynamics. Its structure drives the geodynamo in the outer core, generating the magnetic field that shields the surface from charged cosmic radiation. The primary observables of the Earth's interior are its radial density distribution and derived quantities such as its mass and moment of inertia. These have tradit…
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The Earth's interior reflects its geological evolution, from accretion to present-day dynamics. Its structure drives the geodynamo in the outer core, generating the magnetic field that shields the surface from charged cosmic radiation. The primary observables of the Earth's interior are its radial density distribution and derived quantities such as its mass and moment of inertia. These have traditionally been inferred from gravity and seismic wave propagation, which probe the macroscopic response of matter to gravitational and elastic forces. Here we instead constrain the Earth's density profile using high-energy neutrinos observed by the IceCube Neutrino Observatory at the South Pole. We analyze 10.7 years of predominantly muon-neutrino data spanning 500 GeV--100 TeV, including atmospheric neutrinos produced by cosmic-ray interactions in the Earth's atmosphere and the diffuse astrophysical neutrino flux. Neutrino attenuation depends on both the traversed column density and neutrino energy. By measuring the zenith- and energy-dependent flux suppression, we infer the Earth's radial density profile by fitting a concentric uniform-density shell model that incorporates neutrino fluxes, interaction cross sections, detector response, and glacial-ice systematic uncertainties. From the resulting density posteriors, we derive the Earth's mass and polar moment of inertia as measured by neutrinos. These are the most precise weak-interaction measurements of these quantities to date and are consistent with the Preliminary Reference Earth Model and independent gravitational determinations. Our results demonstrate that neutrinos provide a novel probe of planetary interiors via a distinct physical interaction, complementing gravity and seismology. With improved detectors and precision, neutrinos will further contribute to a multifaceted understanding of the Earth's structure.
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Submitted 7 July, 2026; v1 submitted 2 July, 2026;
originally announced July 2026.
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WavePID: Low-energy flavor identification using single-PMT time series in IceCube
Authors:
The IceCube Collaboration,
R. Abbasi,
M. Ackermann,
J. Adams,
J. A. Aguilar,
M. Ahlers,
J. M. Alameddine,
S. Ali,
N. M. Amin,
K. Andeen,
C. Argüelles,
S. Athanasiadou,
S. N. Axani,
R. Babu,
X. Bai,
A. Balagopal V.,
S. W. Barwick,
V. Basu,
R. Bay,
J. J. Beatty,
J. Becker Tjus,
P. Behrens,
J. Beise,
C. Bellenghi,
S. Benkel
, et al. (395 additional authors not shown)
Abstract:
The IceCube Neutrino Observatory, a cubic-kilometer detector at the South Pole, identifies neutrino flavor through event morphology. Sparse photon detection makes this classification particularly challenging in the 5--100~GeV regime, the energy range relevant for oscillation measurements and searches for physics beyond the Standard Model. We introduce WavePID, a template-based log-likelihood-ratio…
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The IceCube Neutrino Observatory, a cubic-kilometer detector at the South Pole, identifies neutrino flavor through event morphology. Sparse photon detection makes this classification particularly challenging in the 5--100~GeV regime, the energy range relevant for oscillation measurements and searches for physics beyond the Standard Model. We introduce WavePID, a template-based log-likelihood-ratio classifier that exploits nanosecond-scale timing on individual detector modules through three observables: the distance to the reconstructed vertex, the early-charge fraction, and the module-to-module time difference. Evaluated on a cascade-enriched sample selected by a state-of-the-art graph neural network, WavePID improves both cascade purity and classification performance over the neural network alone. This demonstrates that per-module pulse timing carries flavor-identification information complementary to morphology-based classifiers, opening a new physics-motivated observable for low-energy neutrino reconstruction. Geant4 simulations associate this signal with differences in Cherenkov emission geometry between muon tracks and electromagnetic showers. These results motivate exploiting nanosecond-scale pulse timing in future low-energy classifiers and in detector designs with improved per-module timing in next-generation neutrino telescopes.
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Submitted 20 August, 2026; v1 submitted 2 July, 2026;
originally announced July 2026.