The KATRIN Collaboration取得一项新突破。他们的研究发现基于259天KATRIN数据的无菌中微子搜索。相关论文于2025年12月3日发表在《自然》杂志上。

在这里，该课题组研究人员报告了对过去40个月内259个测量天记录的3600万个氚β衰变电子的能谱的分析。eV低于端点。结果排除了由镓异常暗示的参数空间的很大一部分，挑战了中微子-4的说法。与其他中微子消失实验一起，KATRIN探测了从一个eV2的一小部分到几百个eV2的无菌到活跃的质量分裂，排除了混合角度超过百分之几的光无菌中微子。

据介绍，中微子是宇宙中最丰富的基本物质粒子，在粒子物理学和宇宙学中起着至关重要的作用。中微子振荡，发现于25几年前，表明这三种已知的物种相互混合。来自反应堆和放射性强度实验的反常结果1表明可能存在第五种中微子状态，即惰性中微子，它不通过弱力相互作用。卡尔斯鲁厄氚中微子（KATRIN）实验，主要设计用于测量中微子质量主题氚β衰变，也搜索由这些异常暗示的惰性中微子。无菌中微子信号在β衰变能谱中表现为扭曲，其特征是与无菌中微子质量相关的曲率（扭结）的不连续。这种特征只取决于光谱的形状，而不是它的绝对归一化，为反应堆实验提供了一种简单、互补的方法。

附：英文原文

Title: Sterile-neutrino search based on 259 days of KATRIN data

Author: T. Lasserre.

Issue&Volume: 2025-12-03

Abstract: Neutrinos are the most abundant fundamental matter particles in the Universe and play a crucial part in particle physics and cosmology. Neutrino oscillation, discovered about 25years ago, shows that the three known species mix with each other. Anomalous results from reactor and radioactive-source experiments1 suggest a possible fourth neutrino state, the sterile neutrino, which does not interact through the weak force. The Karlsruhe Tritium Neutrino (KATRIN) experiment2, primarily designed to measure the neutrino mass using tritium β-decay, also searches for sterile neutrinos suggested by these anomalies. A sterile-neutrino signal would appear as a distortion in the β-decay energy spectrum, characterized by a discontinuity in curvature (kink) related to the sterile-neutrino mass. This signature, which depends only on the shape of the spectrum rather than its absolute normalization, offers a robust, complementary approach to reactor experiments. Here we report the analysis of the energy spectrum of 36 million tritium β-decay electrons recorded in 259 measurement days within the last 40eV below the endpoint. The results exclude a substantial part of the parameter space suggested by the gallium anomaly and challenge the Neutrino-4 claim. Together with other neutrino-disappearance experiments, KATRIN probes sterile-to-active mass splittings from a fraction of an eV2 to several hundred eV2, excluding light sterile neutrinos with mixing angles above a few per cent.

DOI: 10.1038/s41586-025-09739-9

Source: https://www.nature.com/articles/s41586-025-09739-9