Constraining the core radius and density jumps inside Earth using atmospheric neutrino oscillations

TL;DR

Atmospheric neutrino oscillations can be used to probe Earth's internal structure, including core-mantle boundaries and density jumps, with detectors like INO-ICAL providing crucial data.

Contribution

This work demonstrates how atmospheric neutrino experiments can constrain Earth's internal density distribution and core-mantle boundary location.

Findings

Neutrino oscillation data can distinguish between different Earth density models.

Charge identification improves the sensitivity of internal Earth structure constraints.

Detectors without charge identification still provide valuable constraints, albeit less precisely.

Abstract

Atmospheric neutrinos probe the interior of Earth using weak interactions, and provide information complementary to that of gravitational and seismic measurements. While passing through Earth, multi-GeV neutrinos encounter matter effects due to the coherent forward scattering with ambient electrons, which alter the neutrino oscillation probabilities. These matter effects depend upon the density distribution of electrons inside Earth, and hence, can be used to determine the internal structure of Earth. In this work, we employ a five-layered model of Earth where the layer densities and radii are modified, keeping the mass and moment of inertia of Earth unchanged and respecting the hydrostatic equilibrium condition. We use the proposed INO-ICAL detector as an example of an atmospheric neutrino experiment that can distinguish between neutrinos and antineutrinos efficiently in the multi-GeV energy range. Our analyses demonstrate that such an experiment can simultaneously constrain density jumps inside Earth and locate the core-mantle boundary. The charge identification (CID) capability of the ICAL detector would play a crucial role in obtaining these correlated constraints. An ICAL-like detector without CID capability would also be able to perform this task, albeit with a reduced sensitivity.