在LEGEND-200实验中寻找违反中微子无双β衰变的勒普顿数的第一个结果
H Acharya1,2, N Ackermann3, M Agostini4
1Department of Physics and Astronomy, University of North Carolina, Chapel Hill, North Carolina 27599, USA.
Physical review letters
|January 30, 2026
概括
在LEGEND实验中,使用探测器寻找无中子双β衰变. 没有发现任何信号,为衰变半衰期设定了新的下限,并限制了中子子特性.
科学领域:
- 粒子物理学 粒子物理学
- 核物理 核物理 核物理
- 天体粒子物理学的物理学
背景情况:
- 无中子双β衰变 (0νββ) 是一种假设的过程,可以揭示关于中子质量和违反勒普顿数守恒的信息.
- 寻找0νββ衰变对于理解中微子的基本性质及其在宇宙中的作用至关重要.
- 这项LEGEND实验建立在GERDA和MAJORANA DEMONSTRATOR实验的技术进步之上.
研究的目的:
- 使用高纯度探测器进行对无中子双β衰变的敏感搜索.
- 确定0νββ衰变半衰期的新极限,并限制有效的Majorana中微子质量.
- 为了在LEGEND-200探测器中描述背景水平,以便在未来进行搜索.
主要方法:
- 在低背景液体环境中使用高纯度的,富含Ge的探测器.
- 从LEGEND-200实验中收集和分析了61.0千克/年的数据.
- 结合了GERDA和MAJORANA DEMONSTRATOR实验的数据进行分析.
主要成果:
- 在0νββ衰变信号区域估计的背景水平为0.5_{-0.2}^{+0.3} cts/(keV·ton·yr).
- 没有观察到0νββ衰变信号的证据.
- 在T_{1/2}^{0ν} > 1.9 × 10^{26} 年的0νββ 衰变半衰期上观察到一个新的下限 (90% 置信水平).
结论:
- 传奇协作团队对无中子双β衰变的搜索已经设定了严格的新界限.
- 根据核矩阵元素计算,结果提供了有效Majorana中微子质量的上限,m_{ββ} < 75-200 meV.
- 这些发现推动了对了解中微子性质和基本对称性的探索.
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