On May 20, 2026, the 310th ZY-INS Salon of Zhiyuan College was held in the college’s first-floor lecture hall. Professor Ji Xiangdong, Hongwen Chair Professor at the Tsung-Dao Lee Institute and founder of the PandaX liquid xenon dark matter experiment, was invited as the keynote speaker. He delivered an academic lecture titled "Searching for Dark Matter.

Dark matter is a frontier topic in modern cosmology and particle physics, essential for understanding the large-scale structure of the universe and galaxy evolution. In his report, Professor Ji began with observational evidence from cosmology and systematically introduced the scientific background of the dark matter problem, as well as the theoretical motivation for Weakly Interacting Massive Particles (WIMPs) as a leading dark matter candidate.

By combining the construction process of the PandaX experiment, Ji vividly demonstrated the operation and upgrade of detectors at the Jinping Underground Laboratory in Sichuan, elucidating the technical challenges and scientific value of deep underground experiments. Professor Ji Dongxiang pointed out that although the PandaX experiment has not yet discovered direct evidence of dark matter particles, such "null results" effectively constrain the parameter space of WIMP particles, driving continuous advancements in the study of dark matter properties. He also introduced the team's significant progress in research on rare events, such as solar neutrino detection.

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During the interactive session, students actively raised questions on theoretical background, experimental challenges, and detection prospects. Drawing on international frontiers and the development history of the PandaX experiment, Professor Ji encouraged the audience to maintain their curiosity about fundamental science and to appreciate the long-term, often unpredictable nature of scientific exploration from an interdisciplinary perspective.