Physics colloquium – 2β or No-ν 2β: The Search for Matter Creation with Ge-76

Motivated by the search for neutrinoless double beta decay, – the bizarre process wherein neutrinos are their own antiparticles – the high purity germanium detector technology has advanced as an increasingly sensitive discovery platform. These experiments operate deep underground in the cleanest and most radio-pure environments, with exquisite discovery potential to rare event signals. Building on the success of the Majorana Demonstrator and GERDA, the currently operating LEGEND-200 experiment is rapidly advancing sensitivity by integrating existing technical progress from its predecessor programs. In this talk, I will review recent science results from these experiments, highlighting the broad science reach and focusing on the first results from LEGEND-200. These results set the stage for the next-generation LEGEND-1000, the tonne-scale culmination of the germanium program achieving sensitivity beyond 1028 years and covering the allowed neutrino inverted mass ordering range.

Walter C. Pettus is an Assistant Professor in the Department of Physics at Indiana University, where he joined the faculty in 2020. He had previously conducted postdoctoral work at the University of Washington and Yale University after receiving his Ph.D. from University of Wisconsin. His current research focus is neutrino properties related to the neutrino mass – both direct detection and neutrinoless double beta decay – with a focus on detectors and instrumentation.