Abstract:

Double-beta decay in nuclei is the rarest process that has been experimentally verified so far, and its research is an important subject in both nuclear and particle physics. Unlike charged particles, electrically neutral neutrinos can be Majorana particles, particles that are their own anti-particles. Observation of double-beta decay without the emission of neutrinos (neutrinoless mode) would demonstrate that lepton number is not conserved, and reveal the Majorana nature of neutrinos. If the decay process is mediated by the exchange of a light Majorana neutrino, its rate can be a measure of the absolute scale of the neutrino mass. In 2011, Xe-loaded liquid scintillator was installed in the KamLAND detector, and the KamLAND-Zen double-beta decay search experiment with 136Xe started. In this seminar, the latest results and prospects of KamLAND-Zen and KamLAND will be presented.