Robust Geo-neutrino Results

Abstract: Geo-neutrino observations probe the quantities and distributions of terrestrial heat-producing elements uranium and thorium. The quantities of these elements gauge global radiogenic power, offering insights into the origin and thermal history of the Earth. The distributions reveal the initial partitioning and subsequent transport of these trace elements between metallic core, silicate mantle, and crust types. Ongoing observations at underground sites in Japan and Italy record the energies but not the directions of geo-neutrinos from uranium and thorium. Without directions pointing back to source regions, disentangling the signals from various reservoirs requires resolution of differing rates or energy spectra at separate sites. Due to limited statistics and site contrast, however, the observations at Japan and Italy do not yet measure distinct rates or energy spectra. Further analyses of the observations that derive fluxes, determine a signal from the mantle, and assess the global radiogenic power of uranium and thorium, depend on geochemical assumptions and model predictions. This letter discusses opportunities for eliminating or minimizing these dependencies through observations at dissimilar sites, producing robust geo-neutrino results.