2024-01-05 11:00  P5A-1

Searching for matter creation via neutrinoless double beta decay

Dr. Pin-Jung Chiu

The dominance of matter over antimatter remains a long-standing question in modern physics. The observation of a hypothesized, extremely rare process, neutrinoless double beta decay (0vbb), would demonstrate that neutrinos have a Majorana mass and would establish lepton-number violation. Furthermore, it would provide hints to the neutrino absolute mass scale and the neutrino mass ordering, as well as giving information about the matter-antimatter imbalance of the Universe.

LEGEND is a two-phased project searching for 0vbb in Ge-76. In phase-1, LEGEND-200 will reach a discovery sensitivity of more than 1e27 years (3 sigma) for the half-life of 0vbb with an exposure of 1 tonne-year. The first physics run has started with an initial 142 kg of germanium diodes. In phase-2, LEGEND-1000 aims to improve the discovery sensitivity by another order of magnitude with a 10 tonne-year exposure. By reducing the background levels with several hardware approaches and improved analysis techniques, as well as operating with detectors of the best energy resolution in the field, LEGEND will perform a quasi-background-free search, where an unambiguous signature can be distinguished at the 0vbb decay Q-value of 2039 keV.

In this presentation, I will explain the importance of 0vbb to the fields of neutrino physics and physics beyond the Standard Model, as well as discussing the current status and the future plans of LEGEND.