Séminaires du DPhP: The quest for Lepton Number Violation through 0ν2β decays: LEGEND

by Giuseppe Salamanna (Roma Tre University and INFN)

Monday Dec 8, 2025, 11:00 AM → 12:30 PM Europe/Paris

CEA Paris-Saclay

If neutrinos were Majorana type, they could undergo a yet-to-be-observed process called neutrino-less double-beta decay (0νββ). This scenario would have substantial repercussions on cosmology. So far the best statistical sensitivity on the half-life for the 0νββ process is around 10^26 yr, from experiments employing germanium both as a source and as detector. This sensitivity is attained by combining the current analysis of data from the LEGEND-200, GERDA and MAJORANA Demonstrator experiments. In this seminar I will give an update on the LEGEND project: using a two-stage approach with just short of 200 kg first and then 1000 kg of germanium diodes enriched in the active isotope, 76Ge, LEGEND aims to attain a half-life sensitivity around 10^28 yr, thus probing the inverted-ordering of the neutrino masses. I will review the general concept and design of LEGEND-200 and describe the detector and its current results, from the first data taking periods in 2023 and 2024 at the Laboratori Nazionali del Gran Sasso in Italy. I will also illustrate how the backgrounds affect the sensitivity and in which way they are characterized and suppressed.  
Finally, I will provide an expected timeline for LEGEND-1000 and the related R&D activities, geared at a modular set up with yet reduced background rates.

 

zoom connection: https://cern.zoom.us/j/68399739111?pwd=SGErcHBQYmVLWFZTVE9jdm5xSmdEdz09