Understand
A scintillating bolometer technology based on $^{100}$Mo-enriched lithium molybdate (Li$_2$$^{100}$MoO$_4$) crystals has been developed by LUMINEU to search for neutrinoless double-beta ($0\nu 2\beta$) decay of $^{100}$Mo.
- The results of several low temperature tests at underground environments have proved the reproducibility of high detector performance and crystal radiopurity: in particular $\sim$5--6~keV FWHM energy resolution and at least 9$\sigma$ rejection of $\alpha$'s in the vicinity of the $0\nu 2\beta$ decay of $^{100}$Mo (3034 keV) and below 10~$\mu$Bq/kg bulk activity of $^{228}$Th and $^{226}$Ra.
- A modest acquired exposure (0.1~kg$\times$yr) is a limiting factor of the LUMINEU experiment sensitivity to the $0\nu 2\beta$ decay half-life of $^{100}$Mo ($T_{1/2}$ $\geq$ 0.7$\times$10$^{23}$ yr at 90\% C.L.), however the two-neutrino $2\beta$ decay has been measured with the best up to-date accuracy, $T_{1/2}$ = $\left[6.92 \pm 0.06(\mathrm{stat.}) \pm 0.36(\mathrm{syst.})\right] \times 10^{18}$ yr.
- The applicability of the LUMINEU technology for a tonne-scale $0\nu 2\beta$ decay bolometric project CUPID is going to be demonstrated by the CUPID-0/Mo experiment with $\sim$5~kg of $^{100}$Mo embedded in forty 0.2~kg Li$_2$$^{100}$MoO$_4$ scintillating bolometers.