Current status of the 76Ge neutrinoless double beta decay search and future prospects with LEGEND
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The neutrinoless double beta decay (0nbb) is a very sensitive probe to identify whether neutrinos are Dirac or Majorana particles. A potential discovery of such a process has far reaching consequences for particle physics and cosmology (e.g. leptogenesis) as it would be a sign of physics beyond the Standard Model. Current 76Ge based experiments, GERDA and MAJORANA Demonstrator, benefits from a superior energy resolution and have achieved the lowest background as well as the best half-life sensitivity in the field (T1/2 > 1026 yr). This demonstrates the feasibility of Germanium for a next generation experiment. The LEGEND (Large Enriched Germanium Experiment for Neutrinoless double beta Decay) collaboration has been founded with the goal to build a ton scale experiment and boost the 0nbb half-life sensitivity by two orders of magnitude (1028 yr). An intermediate step using 200 kg of enriched 76Ge detectors will make use of existing GERDA infrastructures at LNGS in Italy over the next decade. After a description of the GERDA experiment, I will present the latest results obtained in May 2018 and finally review the ongoing efforts for LEGEND-200.