Neutrino Geoscience: Review, survey, future prospects

TL;DR

Neutrino geoscience offers a promising approach to better understand Earth's internal heat sources by comparing physics measurements with geological models, addressing current uncertainties in radiogenic heat estimates.

Contribution

This review highlights the potential of neutrino detection to resolve discrepancies in Earth's radiogenic heat estimates and emphasizes future research directions in geoneutrino measurements.

Findings

Physics experiments suggest Earth's radiogenic heat is 15.3-38.2 TW.

Geological models estimate Earth's radiogenic heat at 20±10 TW.

Detection of oceanic geoneutrinos could clarify Earth's internal heat budget.

Abstract

The earth's surface heat flux is 46$\pm$3 TW (terrawatts, 10$^{12}$ watts). Although many assume we know the earth's abundance and distribution of radioactive heat producing elements (i.e., U, Th, and K), estimates for the mantle's heat production varying by an order of magnitude and recent particle physics findings challenge our dominant paradigm. Geologists predict the earth's budget of radiogenic power at 20$\pm$10 TW, whereas particle physics experiments predict 15.3$^{+4.9}_{-4.9}$ TW (KamLAND, Japan) and 38.2$^{+13.6}_{-12.7}$ TW (Borexino, Italy). We welcome this opportunity to highlight the fundamentally important resource offered by the physics community and call attention to the shortcomings associated with the characterization of the geology of the earth. We review the findings from continent-based, physics experiments, the predictions from geology, and assess the degree of misfit between the physics measurements and predicted models of the continental lithosphere and underlying mantle. Because our knowledge of the continents is somewhat uncertain (7.1$^{+2.1}_{-1.6}$ TW), models for the radiogenic power in the mantle (3.5 to 32 TW) and the bulk silicate earth (crust plus mantle) continue to be uncertain by a factor of $\sim$10 and $\sim$4, respectively. Detection of a geoneutrino signal in the ocean, far from the influence of continents, offers the potential to resolve this tension. Neutrino geoscience is a powerful new tool to interrogate the composition of the continental crust and mantle and its structures.