Direct neutrino-mass measurement with sub-electronvolt sensitivity
Direct neutrino-mass measurement with sub-electronvolt sensitivity
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DOI：
10.1038/s41567-021-01463-1
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发表时间：
2022-02-01
期刊：
影响因子：
19.6
通讯作者：
Zeller, G.
中科院分区：
文献类型：
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作者：
Aker, M.;Beglarian, A.;Zeller, G.
自从发现中微子振荡以来，我们知道中微子具有非零质量。然而，中微子的绝对质量尺度仍然未知。在这里，我们报告的有效电子反中微子质量，m（nu）的上限，从卡尔斯鲁厄氚中微子实验的第二次物理运行。在这个实验中，m（nu）是通过高精度测量接近其终点的氚β衰变光谱来探测的。这种方法不依赖于任何宇宙学模型，也不依赖于中微子是狄拉克粒子还是马约拉纳粒子的假设。相对于第一次物理活动，通过增加源活性和降低背景，我们在90%置信水平（CL）下达到了0.7 eV c（-2）的m（nu）灵敏度。对光谱数据的最佳拟合产生m（nu）（2）=（0.26 +/- 0.34）eV（2）c（-4），从而在90%CL下得到m（nu）< 0.9 eV c（-2）的上限。通过将这个结果与第一次中微子质量运动相结合，我们发现在90%CL时，m（nu）< 0.8 eV c（-2）的上限。
Since the discovery of neutrino oscillations, we know that neutrinos have non-zero mass. However, the absolute neutrino-mass scale remains unknown. Here we report the upper limits on effective electron anti-neutrino mass, m(nu), from the second physics run of the Karlsruhe Tritium Neutrino experiment. In this experiment, m(nu) is probed via a high-precision measurement of the tritium beta-decay spectrum close to its endpoint. This method is independent of any cosmological model and does not rely on assumptions whether the neutrino is a Dirac or Majorana particle. By increasing the source activity and reducing the background with respect to the first physics campaign, we reached a sensitivity on m(nu) of 0.7 eV c(-2) at a 90% confidence level (CL). The best fit to the spectral data yields m(nu)(2) = (0.26 +/- 0.34) eV(2) c(-4), resulting in an upper limit of m(nu) < 0.9 eV c(-2) at 90% CL. By combining this result with the first neutrino-mass campaign, we find an upper limit of m(nu) < 0.8 eV c(-2) at 90% CL.