Sensitivity of neutrino oscillations to the Earth’s interior properties

Understanding the Earth’s internal structure remains a major challenge, as traditional geophysical methods face ambiguities in linking seismic observations to temperature, composition, or mass density variations. Atmospheric neutrinos offer a complementary probe: while traversing the Earth, they undergo flavor oscillations that depend on the local electron density, which reflects both mass density and composition. Here, we present EarthProbe, a forward-modeling framework for neutrino propagation and detection, providing a methodology to quantify neutrino sensitivities to the Earth’s interior. Using EarthProbe, we assess the detectability of localized electron-density perturbations, taking the Mantle Transition Zone (410–670 km depth) and the core as case studies. We consider idealized next-generation detectors representing fundamental sensitivity limits and the state-of-the-art instruments KM3NeT/ORCA, Hyper-Kamiokande, and DUNE. While studying the core is within reach of current detector capabilities, probing the MTZ would require improved detector performance. Our methodology lays the foundation for future joint inversion of neutrino and seismic data, providing a framework to advance Earth tomography with neutrinos.