Speaker
Description
Sterile neutrinos could have any mass ranging from eV to the Plank scale. Out of this broad mass range, the keV-scale is one of the most interesting regions because it is a viable dark matter candidate and could provide a better explanation for low-structure astrophysical observations than other dark matter candidates. We are searching for a sterile neutrino in the 1 keV – 20 keV mass range via high precision measurement of the $^{241}$Pu beta spectrum using cryogenic decay energy spectrometry (DES). We have performed a preliminary measurement for 24 hours using a single DES detector containing a 4 Bq mixed Pu source. The measured $^{241}$Pu beta spectrum was consistent with a null hypothesis and therefore we were able to set a preliminary upper limit curve of O(0.01) for the sterile neutrino mixing |U$_\rm{e4}$|$^2$ in the 10 keV mass region. We are currently improving this analysis by including nuclear and atomic effects in the calculation of the beta spectrum, such as screening effect, exchange effect, radiative correction, and overlap corrections. The preliminary results will be presented, as well as projections for the sensitivity of a proposed experiment with improved statistics.
