The standard model of particle physics is a comprehensive theory to describe the basic laws of the micro world, and the non-zero mass of neutrinos is the only experimental phenomenon beyond the standard model. Clarifying the mass origin of neutrinos is a major problem to be solved in contemporary physics. With the theme of neutrino mass, the lecture reviewed the hypothesis and discovery of neutrinos, the mystery of the disappearance of solar neutrinos and the legend of non-zero mass for nearly a century. Facing the historical opportunity, we discuss the basic methods and challenges of experimentally exploring the origin of neutrino mass.

Cai Zheng, associate professor of Astronomy Department of Tsinghua University and deputy director of astronomy technology center of Tsinghua University. He received his doctorate in Astrophysics from the University of Arizona in 2015, engaged in postdoctoral research at the University of California from 2015 to 2019, and won the "Hubble fellow" of NASA in 2016. Joined Tsinghua University in 2019, He was selected into the national talent program (the youth program of the thousand person program of the Organization Department of the CPC Central Committee) and served as the reviewer of magazines such as nature and nature astronomy. He systematically discovered the large-scale structure of the early universe and revealed the metal origin of interstellar space in the early universe. Relevant achievements are listed in nature astronomy And other magazines, and the articles have been cited more than 2000 times. He is also participating in the construction of the world's largest spectral Sky Survey Telescope (MUST).