Enriched Zn\(^{100}\)MoO\(_4\) scintillating bolometers to search for \(0 \nu 2\beta\) decay of \(^{100}\)Mo with the LUMINEU experiment

The LUMINEU project aims at performing a demonstrator underground experiment searching for the neutrinoless double beta decay of the isotope \(^{100}\)Mo embedded in zinc molybdate (ZnMoO\(_4\)) scintillating bolometers. In this context, a zinc molybdate crystal boule enriched in \(^{100}\)Mo to 99.5\% with a mass of 171 g was grown for the first time by the low-thermal-gradient Czochralski technique. The production cycle provided a high yield (the crystal boule mass was 84\% of initial charge) and an acceptable level -- around 4\% -- of irrecoverable losses of the costy enriched material. Two crystals of 59 g and 63 g, obtained from the enriched boule, were tested aboveground at milli-Kelvin temperature as scintillating bolometers. They showed a high detection performance, equivalent to that of previously developed natural ZnMoO\(_4\) detectors. These results pave the way to future sensitive searches based on the LUMINEU technology, capable to approach and explore the inverted hierarchy region of the neutrino mass pattern.