First Results on the Search for Lepton Number Violating Neutrinoless Double- <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mi>β</mml:mi> </mml:math> Decay with the LEGEND-200 Experiment

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 the GERmanium Detector Array (GERDA) experiment and the MAJORANA DEMONSTRATOR experiment, LEGEND-200 has performed a first 0νββ decay search based on 61.0 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_{-0.2}^{+0.3} 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 2.8×10^{26} yr on the half-life of 0νββ decay, reveals no evidence for a signal and sets a new observed lower limit at T_{1/2}^{0ν}>1.9×10^{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.

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Publication Details

Journal
Physical Review Letters
Published
2025-09-29
DOI
https://doi.org/10.1103/25tk-nctn
Citations
5
Primary Topic
Neutrino Physics Research
Type
article
Field-Weighted Citation Impact
9.35

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article

First Results on the Search for Lepton Number Violating Neutrinoless Double- <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mi>β</mml:mi> </mml:math> Decay with the LEGEND-200 Experiment

Karl J. Friston
5 citations
Physical Review Letters
Neutrino Physics Research
9.35
article

First Results on the Search for Lepton Number Violating Neutrinoless Double- <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mi>β</mml:mi> </mml:math> Decay with the LEGEND-200 Experiment

Karl J. Friston
article en
5 citations

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 the GERmanium Detector Array (GERDA) experiment and the MAJORANA DEMONSTRATOR experiment, LEGEND-200 has performed a first 0νββ decay search based on 61.0 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_{-0.2}^{+0.3} 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 2.8×10^{26} yr on the half-life of 0νββ decay, reveals no evidence for a signal and sets a new observed lower limit at T_{1/2}^{0ν}>1.9×10^{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.

Physical Review LettersVol. 136(2)
Roma Tre University (IT), Jagiellonian University (PL), Oak Ridge National Laboratory (US), Los Alamos National Laboratory (US), North Carolina State University (US), University of Padua (IT), University of Liverpool (GB), Lawrence Berkeley National Laboratory (US), University of South Carolina (US), Istituto Nazionale di Fisica Nucleare (IT), Duke University (US), Simon Fraser University (CA), South Dakota School of Mines and Technology (US), University of Milan (IT), University of South Dakota (US), University of Washington (US), University of Zurich (CH), Queen's University (CA), University of L'Aquila (IT), Kurchatov Institute (RU), Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Gran Sasso (IT), University of California System (US), Joint Institute for Nuclear Research (RU), University of Warwick (GB), Max Planck Institute for Physics (DE), Triangle Universities Nuclear Laboratory (US), Institute for Nuclear Research (RU), Leibniz Institute of Polymer Research (DE), Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati (IT), Gran Sasso Science Institute (IT), Max Planck Institute for Nuclear Physics (DE), Czech Technical University in Prague (CZ), University College London (GB), Indiana University (US), Technical University of Munich (DE), Tennessee Technological University (US), University of Milano-Bicocca (IT), Lancaster University (GB), Comenius University Bratislava (SK), University of Tennessee at Knoxville (US), Technische Universität Dresden (DE), University of Tübingen (DE), Leibniz Institute for Crystal Growth (DE), The University of Texas at Austin (US), National Research Nuclear University MEPhI (RU), Politecnico di Milano (IT)
National Science Foundation, U.S. Department of Energy, Strong, National Energy Research Scientific Computing Center, European Commission, Deutsche Forschungsgemeinschaft, Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung, Bundesministerium für Bildung und Forschung, Max-Planck-Gesellschaft, Ministerstwo Edukacji i Nauki, Agentúra na Podporu Výskumu a Vývoja, Office of Science, Natural Sciences and Engineering Research Council of Canada, Science and Technology Facilities Council, Division of Physics, Office of International Science and Engineering, Nuclear Physics, Laboratory Directed Research and Development, Laboratori Nazionali del Gran Sasso, Oak Ridge National Laboratory, Lawrence Berkeley National Laboratory, Los Alamos National Laboratory
Openalex Percentile: Top 2%
Neutrino Physics Research
9.35
DOIOpen Access PDFOpenAlex
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