Our country's research team has directly observed the Migdal effect for the first time, taking a solid step forward in the detection of light dark matter.

Recently, a research team led by the University of Chinese Academy of Sciences and involving multiple schools directly observed the Migdal effect for the first time, providing crucial support for breaking through the threshold bottleneck in the detection of light dark matter. The above results were published in the international academic journal "Nature" on the 15th Beijing time. According to Professor Liu Qian of the University of Chinese Academy of Sciences, the team independently developed a super-sensitive detection device using a combination of "microstructure gas detector + pixel readout chip", which is equivalent to a "camera" that can capture the process of releasing electrons in a single atom movement. Using a compact deuterium-deuterium fusion accelerator neutron source, the team bombarded gas molecules inside the "camera", simultaneously producing atomic nucleus recoil and Migdal electrons, forming a unique trajectory with a "common vertex". By analyzing this characteristic, the team successfully distinguished this "Migdal event" from background interference such as gamma rays and cosmic rays. This directly confirms the Migdal effect predicted by quantum mechanics in 1939 for the first time. Yue Qian, the lead scientist of the Jinping CDEX dark matter experiment, believes that this achievement not only fills the long-term gap in experimental verification of the Migdal effect, consolidates the theoretical basis of the Migdal effect, but also fully demonstrates the capabilities of high-quality gas detection technology in China, taking a solid first step towards the application of light-mass dark matter detection.