New calculation of the geo-neutrino energy spectrum and its implication

TL;DR

This paper presents a new, more accurate calculation of the geo-neutrino energy spectrum from Uranium-238 and Thorium-232 decay, with implications for neutrino detection experiments and earth sciences.

Contribution

It introduces a comprehensive geo-neutrino flux model based on updated nuclear data and advanced decay corrections, improving upon previous estimates.

Findings

Notable differences in energy spectrum shape compared to previous models.

Significant deviations in predicted IBD yields for Uranium-238 and Thorium-232.

Potential 10-20% impact on geo-neutrino measurement analyses.

Abstract

The energy spectrum of geo-neutrinos plays a vital role in the experimental measurement of geo-neutrinos that have profound implications for both particle physics and earth sciences. In this letter, we present a state-of-the-art calculation of the energy spectrum of geo-neutrinos originating from the beta decay of Uranium-238 and Thorium-232. Our calculation is underpinned by the latest updates in the nuclear database, accounts for previously overlooked forbidden transitions, and incorporates advanced corrections for the beta decay. This brand new geo-neutrino flux model, compared to the widely-used estimates from Enomoto, reveals notable distinction in the energy spectrum shape because of our comprehensive approach. When considering the inverse beta decay (IBD) detection process, our findings show a significant deviation in the predicted IBD yield of around 4% for Uranium-238 and 9% for Thorium-232 decay chains. The implications of using the new geo-neutrino flux model for the experimental analysis are substantial, potentially affecting the analysis results of geo-neutrino measurements of KamLAND and Borexino by around 10% to 20%. Our study represents a significant advancement in geo-neutrino research, establishing a new benchmark for accuracy and reliability in the field.