Proposed experiments to detect keV range sterile neutrinos using energy-momentum reconstruction of beta decay or K-capture events

TL;DR

This paper reviews methods for detecting keV-range sterile neutrinos, emphasizing energy-momentum reconstruction of beta decay or K-capture events using trapped atoms, and identifies promising isotopes and experimental challenges.

Contribution

It proposes a novel experimental approach using energy-momentum reconstruction with trapped atoms to detect sterile neutrinos in the keV range, highlighting specific isotopes and measurement requirements.

Findings

Sterile neutrinos in the 5-10 keV mass range could be detectable.

Measurement of X-ray, Auger electrons, and atomic recoil is crucial.

Detection sensitivity could reach coupling levels of 10^{-10} to 10^{-11}.

Abstract

Sterile neutrinos in the keV mass range may constitute the galactic dark matter. Various proposed direct detection and laboratory searches are reviewed. The most promising method in the near future is complete energy-momentum reconstruction of individual beta-decay or K-capture events, using atoms suspended in a magneto-optical trap. A survey of suitable isotopes is presented, together with the measurement precision required in a typical experimental configuration. It is concluded that among the most promising are the K-capture isotopes 131Cs, which requires measurement of an X-ray and several Auger electrons in addition to the atomic recoil, and 7Be which has only a single decay product but needs development work to achieve a trapped source. A number of background effects are discussed. It is concluded that sterile neutrinos with masses down to the 5-10 keV region would be detectable, together with relative couplings down to the level 10-10-10-11 in a 1-2 year running time.