New type of detector enables deeper understanding of the universe

The underground “Jiangmen Underground Neutrino Observatory (JUNO)” near Jiangmen city in the Guangdong Province, which was prepared with the participation of researchers from the PRISMA+ Cluster of Excellence at Johannes Gutenberg University Mainz (JGU), has successfully completed the filling of its 20,000 tons of liquid scintillator and begun data taking. After more than a decade of preparation and construction, JUNO is the first of a new generation of very large neutrino experiments to reach this stage. Initial trial operation and data taking show that key performance indicators met or exceeded design expectations, enabling JUNO to tackle one of this decade’s major open questions in particle physics: the ordering of neutrino masses—whether the third mass state (ν₃) is heavier than the second (ν₂).