First Results on the Search for Lepton Number Violating Neutrinoless Double Beta Decay with the LEGEND-200 Experiment
Research output: Preprint/Documentation/Report › Preprint
Contributors
- Chair of Nuclear Physics
- Leibniz Institute of Polymer Research Dresden
Abstract
The LEGEND collaboration is searching for neutrinoless double beta ($0νββ$) decay by operating high-purity germanium detectors enriched in $^{76}$Ge in a low-background liquid argon environment. Building on key technological innovations from GERDA and the MAJORANA DEMONSTRATOR, LEGEND-200 has performed a first $0νββ$ decay search based on 61 kg yr of data. Over half of this exposure comes from our highest performing detectors, including newly developed inverted-coaxial detectors, and is characterized by an estimated background level of $0.5^{+0.3}_{-0.2}$ cts/(keV ton yr) in the $0νββ$ decay signal region. A combined analysis of data from GERDA, the MAJORANA DEMONSTRATOR, and LEGEND-200, characterized by a 90% confidence level exclusion sensitivity of $2.8 \times 10^{26}$ yr on the half-life of $0νββ$ decay, reveals no evidence for a signal and sets a new observed lower limit at $T^{0ν}_{1/2} > 1.9 \times 10^{26}$ yr (90% confidence level). Assuming the decay is mediated by Majorana neutrinos, this corresponds to an upper limit on the effective Majorana mass in the range $m_{ββ} < 75-200$ meV, depending on the adopted nuclear matrix element.
Details
| Original language | English |
|---|---|
| Publication status | Published - 1 May 2025 |
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External IDs
| ORCID | /0000-0002-0406-5800/work/191039679 |
|---|---|
| ORCID | /0000-0002-6705-7138/work/191042079 |
Keywords
Keywords
- High Energy Physics - Experiment, Nuclear Experiment