AMoRE Experiment Sets New Limits on Neutrinoless Double Beta Decay

An international research team, the AMoRE collaboration, has set new constraints on neutrinoless double beta decay, a rare nuclear process. This search, conducted using molybdate scintillating crystals at milli-Kelvin temperatures in the Yangyang Underground Laboratory in Korea, aims to measure neutrino mass and probe matter-antimatter symmetry. The experiment involves observing the simultaneous decay of two neutrons into two protons without neutrino emission, a phenomenon that, if observed, would confirm neutrinos and antineutrinos are the same particle, as theorized by Ettore Majorana. The team prepared kilograms of molybdenum-100, a radioactive isotope, in crystal form. Interactions within these crystals produce heat and light signals, detected by a low-temperature system 700 meters underground. While the AMoRE-I experiment achieved the best sensitivity for this type of decay in molybdenum-100, no signal was found. This "background-only result" established an improved limit on the decay half-life of Mo-100. Future searches will utilize detection systems at the new Yemilab in Korea, 1000 meters underground, with the AMoRE-II phase preparing to collect data within a year, aiming to be among the world's most sensitive searches for this decay.