近日，The MicroBooNE Collaboration发现了在MicroBooNE上用两个中微子束搜索光无菌中微子。该项研究成果发表在2025年12月3日出版的《自然》上。

在这里，课题组对MicroBooNE液氩时间投影室10在两个加速器中微子束中获得的数据进行了分析，以排除LSND和MiniBooNE异常在95%置信水平（CL）下的单光无菌中微子解释。

此外，该研究组排除了可以解释镓异常的参数空间的显着部分。这是首次对两个加速器中微子束进行测量，以打破中微子出现和消失之间的简并，否则会削弱对惰性中微子假设的敏感性。研究组没有发现ν_μ→ν_e的跃迁或ν_e的消失，这将表明非标准的风味振荡。他们的结果表明，先前的异常观测与ν_μ→ν_e跃迁不能通过引入一个单一的惰性中微子状态来解释。

研究人员表示，ν_e、ν_μ和ν_τ这三种不同的中微子的存在是粒子物理标准模型的核心原则。量子力学的干涉可以让一种初始味道的中微子在一段时间后被探测到为另一种味道，这一过程被称为中微子振荡。一些与这三种不同的反常现象的观测结果促使人们提出了一个假设，即存在另一种不与物质直接相互作用的中微子状态，称为“无菌”中微子，ν_s。这包括来自液体闪烁体中微子探测器（LSND）实验和微型助推器中微子实验（MiniBooNE）的异常观测，与ν_μ→ν_e在与三中微子图像不一致的距离上跃迁。

附：英文原文

Title: Search for light sterile neutrinos with two neutrino beams at MicroBooNE

Author: J. H. Jo.

Issue&Volume: 2025-12-03

Abstract: The existence of three distinct neutrino flavours, νe, νμ and ντ, is a central tenet of the Standard Model of particle physics1,2. Quantum-mechanical interference can allow a neutrino of one initial flavour to be detected sometime later as a different flavour, a process called neutrino oscillation. Several anomalous observations inconsistent with this three-flavour picture have motivated the hypothesis that an additional neutrino state exists, which does not interact directly with matter, termed as ‘sterile’ neutrino, νs (refs.3,4,5,6,7,8,9). This includes anomalous observations from the Liquid Scintillator Neutrino Detector (LSND)3 experiment and Mini-Booster Neutrino Experiment (MiniBooNE)4,5, consistent with νμ→νe transitions at a distance inconsistent with the three-neutrino picture. Here we use data obtained from the MicroBooNE liquid-argon time projection chamber10 in two accelerator neutrino beams to exclude the single light sterile neutrino interpretation of the LSND and MiniBooNE anomalies at the 95% confidence level (CL). Moreover, we rule out a notable portion of the parameter space that could explain the gallium anomaly6,7,8. This is one of the first measurements to use two accelerator neutrino beams to break a degeneracy between νe appearance and disappearance, which would otherwise weaken the sensitivity to the sterile neutrino hypothesis. We find no evidence for either νμ→νe flavour transitions or νe disappearance that would indicate non-standard flavour oscillations. Our results indicate that previous anomalous observations consistent with νμ→νe transitions cannot be explained by introducing a single sterile neutrino state.

DOI: 10.1038/s41586-025-09757-7

Source: https://www.nature.com/articles/s41586-025-09757-7