中山大学唐健团队近日实现了利用电子-中微子散射测试镓异常。2025年7月1日出版的《高能物理杂志》发表了这项成果。
镓异常是在使用51Cr放射源校准GALLEX和SAGE期间观察到的中微子中无法解释的缺陷，最近由BEST证实。对这一缺陷的可能解释包括对Ga中中微子吸收截面的高估、对源活动的不正确测量或无菌中微子的存在。然而，由于这种缺陷仅在Ga探测器中观察到，因此无法区分各种提案。
因此，研究组提出了一个使用相同放射源但使用不同检测方法（电子中微子散射）的实验。他们讨论了这种实验的潜在位置，估计了主要背景和预期事件率，考虑了各种目标质量和源位置。即使异常不是由检测方法引起的，这样的实验也可以通过使用光谱信息或观察散射角来独立确定51Cr衰变的分支比。正如无菌中微子模型所预测的那样，它对异常的最终基线依赖性也很敏感。
附：英文原文
Title: Testing the Gallium anomaly using electron-neutrino scattering
Author: Ciuffoli, Emilio, Evslin, Jarah, Gao, Ruixuan, Lin, Haixing, Tang, Jian
Issue&Volume: 2025-07-01
Abstract: The Gallium anomaly is an unexplained deficit in the neutrinos observed during the calibration of GALLEX and SAGE using a 51Cr radioactive source and recently confirmed by BEST. The possible explanations for this deficit include an overestimation of the neutrino absorption cross section in Ga, an incorrect measurement of the source activity or the existence of sterile neutrinos. However, as this deficit has only been observed in Ga detectors, it has not been possible to distinguish among various proposals. Therefore, we propose an experiment using the same radioactive source but with a different detection method, electron-neutrino scattering. We discuss potential locations for such an experiment, estimating the main backgrounds and expected event rates, considering various target masses and source positions. Even if the anomaly does not result from the detection method, such an experiment can provide an independent determination of the branching ratio of the 51Cr decay by using the spectral information or observing the scattering angle. It is also sensitive to an eventual baseline dependence of the anomaly, as is predicted in sterile neutrino models.
DOI: 10.1007/JHEP07(2025)017
Source: https://link.springer.com/article/10.1007/JHEP07(2025)017