Sensitivity of Next-Generation Tritium Beta-Decay Experiments for keV-Scale Sterile Neutrinos

TL;DR

This paper evaluates how upcoming large-scale tritium beta-decay experiments can detect keV-scale sterile neutrinos, which are potential dark matter candidates, highlighting the experimental sensitivities and challenges involved.

Contribution

It demonstrates that a KATRIN-like experiment can achieve high sensitivity to active-sterile neutrino mixing and assesses the impact of theoretical and systematic uncertainties.

Findings

Sensitivity to mixing angle of about 10^{-8}

Theoretical uncertainties have minimal impact on sensitivity

Systematic effects pose significant experimental challenges

Abstract

We investigate the sensitivity of tritium $\beta$-decay experiments for keV-scale sterile neutrinos. Relic sterile neutrinos in the keV mass range can contribute both to the cold and warm dark matter content of the universe. This work shows that a large-scale tritium beta-decay experiment, similar to the KATRIN experiment that is under construction, can reach a statistical sensitivity of the active-sterile neutrino mixing of $\sin^2\theta \sim 10^{-8}$. The effect of uncertainties in the known theoretical corrections to the tritium $\beta$-decay spectrum were investigated, and found not to affect the sensitivity significantly. It is demonstrated that controlling uncorrelated systematic effects will be one of the main challenges in such an experiment.