Abstract: Why is the universe dominated by matter, and not antimatter? Neutrinos, with their changing flavors and tiny masses, could provide an answer. If the neutrino is a Majorana particle, meaning that it is its own antiparticle, it would reveal the origin of the neutrino’s mass, demonstrate that lepton number is not a conserved symmetry of nature, and provide a path to leptogenesis in the early universe. To discover whether this is the case, we must search for neutrinoless double-beta decay, a theorized process that would occur in some nuclei. By searching for this extremely rare decay, we can explore new physics at energy scales that only existed in the seconds following the Big Bang. 

Detecting this extremely rare process, however, requires us to build very large detectors with very low background rates.  Experiments using germanium detectors, like the Majorana Demonstrator, which is currently running, and Large Enriched Germanium Experiment for Neutrinoless Double beta decay (LEGEND), which is moving forward quickly, are a promising strategy to explore lifetimes of up to 10²⁸ years. The current generation of experiments have achieved the lowest backgrounds of any technique and have a clear path forward to move to the ton-scale. I’ll present recent results from the Demonstrator, an update on LEGEND-200’s progress, and prospects for LEGEND-1000.