IceCube Neutrino Attenuation Yields Weak-Interaction Constraints on Earth's Radial Density Profile

Researchers modeled Earth as concentric uniform-density shells and fit the observed zenith- and energy-dependent flux suppression caused by neutrino charged-current interactions. The dataset combined atmospheric neutrinos with the diffuse astrophysical flux, incorporating detector response and glacial-ice systematics to derive posterior distributions on shell densities. This approach directly constrains column density via weak interactions, independent of elastic moduli that govern seismic wave speeds.

The resulting mass and moment-of-inertia values agree with both PREM and satellite-gravity determinations within uncertainties, demonstrating that neutrinos sample the same bulk structure through a fundamentally different physical channel. Because attenuation depends on nucleon density rather than shear or compressional velocities, the method is insensitive to partial melting or anisotropy that can bias seismic inferences of the outer core.

Earlier proposals for neutrino tomography remained theoretical; this work supplies the first data-driven implementation at planetary scale. Future cubic-kilometer-scale detectors such as IceCube-Gen2 will tighten energy and angular resolution, enabling discrimination between competing compositional models of the lower mantle that seismic data alone cannot resolve.

Improved statistics above 10 TeV will also test whether the inner-core density jump inferred from neutrinos deviates from PREM values, providing an independent cross-check on light-element partitioning during core crystallization.