Discovering the origin of matter with LEGEND

by Julieta Gruszko

Monday 26 Oct 2026, 12:45 → 13:45 America/New_York

D-122 (P. Grannis Seminar Room)

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 the creation of matter 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 ultra-rare process, however, requires us to build very large detectors with very low background rates. The LEGEND experiment searches for the neutrinoless double-beta decay of 76Ge with hundreds of kilograms of detectors. I’ll discuss LEGEND-200’s first results and our progess towards building LEGEND-1000, including the machine learning-based work we’re doing to make these experiments even more sensitive.