Captures of Hot and Warm Sterile Antineutrino Dark Matter on EC-decaying Ho-163 Nuclei

TL;DR

This paper explores the potential to detect relic sterile antineutrinos, which could be hot or warm dark matter, by capturing them on Ho-163 nuclei and analyzing the resulting signals against background decay.

Contribution

It provides calculations of capture rates of relic sterile antineutrinos on Ho-163, demonstrating the feasibility of detection with suitable experimental setups.

Findings

Detection of sterile antineutrinos is theoretically possible with large enough targets.

Energy resolution is crucial for distinguishing signals from background.

Relic sterile antineutrinos could be observable as dark matter candidates.

Abstract

Capturing low-energy electron antineutrinos on radioactive Ho-163 nuclei, which decay into Dy-163 via electron capture (EC), is a noteworthy opportunity to detect relic sterile antineutrinos. Such hypothetical particles are more or less implied by current experimental and cosmological data, and they might be a part of hot dark matter or a candidate for warm dark matter in the Universe. Using the isotope Ho-163 as a target and assuming reasonable active-sterile antineutrino mixing angles, we calculate the capture rate of relic electron antineutrinos against the corresponding EC-decay background in the presence of sterile antineutrinos at the sub-eV or keV mass scale. We show that the signature of hot or warm sterile antineutrino dark matter should in principle be observable, provided the target is big enough and the energy resolution is good enough.