近日，365体育投注:大学郑阳恒团队报道了中子轰击引起的米格达尔效应的直接观测。2026年1月14日出版的《自然》杂志发表了这篇成果。

对暗物质的探索当前聚焦于质量介于兆电子伏特至吉电子伏特之间的假设性轻粒子。这些粒子在实验中仅会留下极其微弱的信号。提升对轻粒子物质实验灵敏度的潜在途径依赖于米格达尔效应——该效应描述了原子与中性暗物质碰撞发生瞬时加速时，会产生可探测的电子喷射过程。然而，尽管使用中性射束的受控实验理论上同样能产生米格达尔效应，但该效应的直接实验观测始终缺失，这使依赖此效应的探测实验可靠性受到质疑。

研究组通过中子-原子核碰撞实验首次直接观测到米格达尔效应，基于从近百万次记录事件中筛选出的6个候选事例，达到了5倍标准偏差的统计显著性。实验测得米格达尔效应截面与原子核反冲截面的比值为(4.9-1.9+2.6)×10-5，其中原子核反冲能量超过35千电子伏特当量，电子反冲能量范围为5-10千电子伏特。这些发现与理论预测相符。此项工作填补了长期存在的实验验证空白，不仅巩固了米格达尔效应的理论基础，更为其在轻暗物质探测领域的应用开辟了道路。

附：英文原文

Title: Direct observation of the Migdal effect induced by neutron bombardment

Author: Yi, Difan, Liu, Qian, Chen, Shi, Dong, Chunlai, Feng, Huanbo, Gao, Chaosong, Huang, Wenqian, Jing, Xinmei, Kong, Lingquan, Li, Jin, Li, Peirong, Liang, Enwei, Ma, Ruiting, Su, Chenguang, Su, Liangliang, Sun, Junwei, Wang, Dong, Wang, Junrun, Wei, Zheng, Yao, Zeen, Yu, Yunlinchen, Zhang, Yu, Zhou, Shiqiang, Zhou, Zhuo, Zhu, Bin, Zuo, Jie, Liu, Hongbang, Sun, Xiangming, Wu, Lei, Zheng, Yangheng

Issue&Volume: 2026-01-14

Abstract: The search for dark matter focuses now on hypothetical light particles with masses ranging from MeV to GeV (refs.1,2,3,4,5,6,7,8,9,10,11,12). These particles would leave very faint signals experimentally. A potential avenue for enhancing experimental sensitivity to light matter relies on the Migdal effect13,14,15, which involves the detectable ejection of electrons following the instantaneous accelerations of atoms colliding with neutral dark matter. However, although the Migdal effect could be equally generated in controlled experiments with neutral projectiles, a direct experimental observation of this effect is missing, casting doubt on the reliability of detection experiments relying on this effect. Here we report the direct observation of the Migdal effect in neutron–nucleus collisions, achieving a statistical significance of 5 standard deviations, which rests on 6 candidate events selected out of almost 106 recorded events. Our experiments have determined the ratio of the Migdal cross-section to the nuclear recoil cross-section to be 4.9+2.6-1.9×10-5, in which nuclear recoils exceed 35keVee and electron recoils span 5–10keV. These findings are consistent with theoretical predictions. This work resolves a long-standing gap in experimental validation, which not only strengthens the theoretical foundation of the Migdal effect but also paves the way for its application in light dark matter detection.

DOI: 10.1038/s41586-025-09918-8

Source: https://www.nature.com/articles/s41586-025-09918-8