STEREO合作团队取得一项新突破。他们的研究认为²³⁵U裂变的STEREO中微子谱否定了无菌中微子假说。相关论文于2023年1月11日发表于国际顶尖学术期刊《自然》杂志上。

研究团队提出了STEREO生成的全套数据的分析，确认了观测到的异常，同时拒绝了轻无菌中微子的假设。STEREO安装在Laue-Langevin研究所(ILL)的研究反应堆上，精确测量了与²³⁵U裂变相关的反中微子能谱。探测器的分割及其与致密核心的极短距离是STEREO分析的关键特性。测量的反中微子能谱表明，异常源于用于预测的核实验数据的偏差。

他们的结果支持了标准模型的中微子含量，并为²³⁵U反中微子能谱建立了新的参考。研究人员预计，这一结果将有助于对中微子基本性质进行更精细的测试，而且还将有助于反应堆物理学以及天体物理学或地中微子观测的基准模型和核数据。

研究人员表示，在过去的中微子测量中的异常导致了这些粒子具有非零质量，并且在传播时在其三种味道之间振荡。在2010年，在核反应堆发射的反中微子光谱中观察到类似的异常，引发了存在一种补充中微子状态的假设，这种状态是无菌的，即不通过弱相互作用相互作用。STEREO实验被设计用来研究这一猜想，这可能会扩展粒子物理学的标准模型。

附：英文原文

Title: STEREO neutrino spectrum of 235U fission rejects sterile neutrino hypothesis

Author: anonymous

Issue&Volume: 2023-01-11

Abstract: Anomalies in past neutrino measurements have led to the discovery that these particles have non-zero mass and oscillate between their three flavours when they propagate. In the 2010s, similar anomalies observed in the antineutrino spectra emitted by nuclear reactors have triggered the hypothesis of the existence of a supplementary neutrino state that would be sterile, that is, not interacting by means of the weak interaction1. The STEREO experiment2,3,4,5,6 was designed to investigate this conjecture, which would potentially extend the standard model of particle physics. Here we present an analysis of the full set of data generated by STEREO, confirming observed anomalies while rejecting the hypothesis of a light sterile neutrino. Installed at the Institut Laue–Langevin (ILL) research reactor, STEREO accurately measures the antineutrino energy spectrum associated to the fission of 235U. The segmentation of the detector and its very short distance to the compact core are crucial properties of STEREO for our analysis. The measured antineutrino energy spectrum suggests that anomalies originate from biases in the nuclear experimental data used for the predictions7,8. Our result supports the neutrino content of the standard model and establishes a new reference for the 235U antineutrino energy spectrum. We anticipate that this result will allow progress towards finer tests of the fundamental properties of neutrinos but also to benchmark models and nuclear data of interest for reactor physics9,10 and for observations of astrophysical or geoneutrinos11,12.

DOI: 10.1038/s41586-022-05568-2

Source: https://www.nature.com/articles/s41586-022-05568-2