Current status of LEGEND: Searching for neutrinoless double-beta decay in ⁷⁶Ge: Part I

Neutrinoless double-beta decay(0νββ) decay is a hypothetical process that violates lepton number, and whose observation would unambiguously indicate that neutrinos are Majorana fermions. In the standard inverted-ordering neutrino mass scenario, the minimum possible value of m_ββ corresponds to a half-life around 10²⁸ yr for 0νββ decay in ⁷⁶Ge, which is the target of the next generation of experiments. The current limits of GERDA and MAJORANA DEMONSTRATOR indicate a half-life higher than 10²⁶ yr. These experiments use high-purity germanium (HPGe) detectors that are highly-enriched in ⁷⁶Ge. They have achieved the best intrinsic energy resolution and the lowest background rate in the signal search region among all 0νββ experiments. Taking advantage of these successes, a new international collaboration - the Large Enriched Germanium Experiment for Neutrinoless ββ Decay (LEGEND) - has been formed to build a ton-scale experiment with discovery potential covering the inverse-ordering neutrino mass range in a decade, following a phased approach. This first part of LEGEND proceedings describes GERDA and MAJORANA DEMONSTRATOR capabilities and the general plan of LEGEND to reach the goal, while the second part is focused in the status of the first stage of LEGEND, LEGEND-200.