Heavy sterile neutrino in dark matter searches

TL;DR

This paper explores potential detection methods for heavy sterile neutrinos (~50 keV) as dark matter candidates, emphasizing the need for novel experimental techniques due to their non-relativistic nature and low kinetic energy.

Contribution

It systematically evaluates various experimental approaches for detecting heavy sterile neutrinos, highlighting the challenges and proposing feasible detection strategies.

Findings

Estimated event rates for different detection methods.

Identification of suitable materials and conditions for detection.

Potential signals in beta decay experiments like KATRIN.

Abstract

Sterile neutrinos are possible dark matter candidates. We examine here possible detection mechanisms, assuming that the neutrino has a mass of about 50 keV and couples to the ordinary neutrino. Even though this neutrino is quite heavy, it is non relativistic with a maximum kinetic energy of 0.1 eV. Thus new experimental techniques are required for its detection. We estimate the expected event rate in the following cases: i) Measure electron recoils in the case of materials with very low electron binding. ii) Low temperature crystal bolometers. iii) Spin induced atomic excitations at very low temperatures, leading to a characteristic photon spectrum. iv) Observation of resonances in antineutrino absorption by a nucleus undergoing electron capture. v) Neutrino induced electron events beyond the end point energy of beta decaying systems, e.g. in the tritium decay studied by KATRIN.