Speaker
Description
If neutrinos were the one (and only) instance of elementary particles of the Majorana type, they could undergo a hypothetical process violating lepton number, the so-called neutrino-less double-beta decay (0νββ). If 0νββ indeed were observed, that would be enough to claim the Majorana nature of neutrinos. This would have substantial repercussions on cosmology and provide a possible mechanism for the matter-antimatter imbalance in the universe.
Several experiments have been conceived which search for 0νββ in a handful of isotopes. A variety of experimental techniques are being employed in the quest. So far the best statistical sensitivity on the half-life for the 0νββ process is around 10^26 yr and belongs to experiments employing germanium both as a source and as a semi-conducting detector. This sensitivity is attained by combining the current analysis of data from the LEGEND-200 experiment and the legacy of its predecessors, the GERDA and MAJORANA Demonstrator experiments.
In this talk I will give an update on the “LEGEND” project: using a two-stage approach with about 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 of 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 to get LEGEND-1000 operational and the related R&D and procurement activities.
This work is supported by the U.S. DOE and the NSF, the LANL, ORNL and LBNL LDRD programs; the European ERC and Horizon programs; the German DFG, BMBF, and MPG; the Italian INFN; the Polish NCN and MNiSW; the Czech MEYS; the Slovak RDA; the Swiss SNF; the UK STFC; the Canadian NSERC and CFI; the LNGS and SURF facilities.
| Collaboration(s) | The LEGEND Collaboration |
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