First Physics Results from LEGEND-200 Published in Physical Review Letters

We are proud to announce the publication of the first physics results from the LEGEND-200 experiment in Physical Review Letters

(accepted September 29, 2025)

The paper, titled
“First Results on the Search for Lepton Number Violating Neutrinoless Double-Beta Decay with the LEGEND-200 Experiment”,
presents the initial data from the world’s most sensitive search for neutrinoless double-beta decay of 76Ge.

LEGEND follows a staged approach. LEGEND-200, operating up to 200 kg of enriched germanium detectors immersed in liquid argon at the INFN Gran Sasso National Laboratory (LNGS), represents the first stage of the LEGEND scientific program. While LEGEND-200 will continue data taking toward a discovery sensitivity beyond 1027 years, the next stage, LEGEND-1000, with a total detector mass of one ton of enriched germanium, is currently under preparation. The ultimate goal of the LEGEND program is to search for lepton-number violation and the Majorana nature of neutrinos with a discovery sensitivity beyond 1028 years.

This first milestone of LEGEND-200 marks an important step toward answering one of the central questions of modern physics — whether neutrinos are their own antiparticles and how this relates to the origin of matter in the universe.

Read the accepted paper here:

Physical Review Letters – Accepted Paper

LEGEND-200 presents unblinded signal region at Neutrino 2024

After a first glimpse of LEGEND-200 data at TAUP 2023, LEGEND-200 continued accumulating exposure and performed its first unblinding of the signal region. These results were presented at Neutrino 2024, which include the first half-life limit of 0νββ from LEGEND data! The Collaboration was represented by 1 talk and 12 posters covering a wide rage of topics including background modeling, application of machine learning methods, and the use of a novel scintillating material for background suppression.

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LEGEND-200 presents first physics data at TAUP 2023

Following the successful commissioning of LEGEND-200, we are thrilled to provide you with an overview of our journey from construction to the collection of physics data at TAUP 2023. Be among the first to catch a glimpse of the data we've collected! LEGEND is represented at TAUP with 3 talks and 7 posters. We will cover all topics reaching from the construction of LEGEND-200, its first physics data, to the prospects for LEGEND-1000. 

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