First results on the search for the lepton number violating neutrinoless double beta decay from the LEGEND experiment

by Luigi Pertoldi (TUM & INFN)

Wednesday 2 Apr 2025, 14:30 → 15:30 Europe/Rome

Aula B (Vasca Navale 84)

The LEGEND project is a multi-phase experimental program designed to search for neutrinoless double beta (0νββ) decay in Ge-76 with the ultimate goal of probing beyond the inverted ordering of neutrino masses. This process, if observed, would create matter without antimatter, violating lepton number conservation and demonstrating that neutrinos are Majorana particles. LEGEND-200 is the first phase of this effort, operating at the Gran Sasso National Laboratory. It employs high-purity germanium detectors immersed in an ultra-low background liquid argon environment, which is instrumented with optical sensors to detect its scintillation light. This setup acts as both a passive and active veto against residual backgrounds, significantly enhancing the experiment’s sensitivity. In this seminar, I will present the first results from LEGEND-200, including detector performance, background suppression strategies, and the current limit on the half-life of 0νββ decay in Ge-76. I will also summarize the status of the planning for LEGEND-1000, the final phase of the experiment, which is designed for an unambiguous discovery of 0νββ decay beyond the inverted ordering by operating 1 ton of germanium detectors.

seminario-legend200-pertoldi.pdf