Unveiling the outer core composition with neutrino oscillation tomography

TL;DR

This paper proposes using atmospheric neutrino tomography to determine the Earth's outer core composition, specifically detecting hydrogen presence, which could resolve longstanding geophysical debates.

Contribution

It introduces a novel neutrino-based method to identify light elements in the Earth's outer core, focusing on hydrogen detection with future detector capabilities.

Findings

Neutrino detectors can detect 1 wt% hydrogen in the core within 50 years.

Next-generation detectors could perform this measurement in a few years.

Discrimination between FeNiH and FeNiSi(x)O(y) models is feasible within 15 years.

Abstract

In the last 70 years, geophysics has established that the Earth's outer core is an FeNi alloy containing a few percent of light elements, whose nature and amount remain controversial today. Besides the classical combinations of silicon and oxygen, hydrogen has been advocated as the only light element that could account alone for both the density and velocity profiles of the outer core. Here we show how this question can be addressed from an independant viewpoint, by exploiting the tomographic information provided by atmospheric neutrinos, weakly-interacting particles produced in the atmosphere and constantly traversing the Earth. We evaluate the potential of the upcoming generation of atmospheric neutrino detectors for such a measurement, showing that they could efficiently detect the presence of 1 wt% of hydrogen in an FeNi core in 50 years of concomitant data taking. We then identify the main requirements for a next-generation detector to perform this measurement in a few years timescale, with the further capability to efficiently discriminate between FeNiH and FeNiSi(x)O(y) models in less than 15 years.