讲座题目： The Proton Remains Puzzling

演讲人：  高海燕（美国杜克大学教授）

时间地点： 2020年5月28日 周四 9：00-11:00  Zoom网络会议

  Nucleons (protons and neutrons) are the building blocks of atomic nuclei, and are responsible for more than 99% of the visible matter in the universe. Despite decades of efforts in studying its internal structure, there are still a number of puzzles surrounding the proton such as its spin, mass, and charge radius. The proton charge radius puzzle developed about ten years ago refers to a 5-7 sigma discrepancy between the ultrahigh precise values of the proton charge radius determined from muonic hydrogen Lamb shift measurements and the CODATA values compiled from electron-proton scattering experiments and hydrogen spectroscopy measurements. In this talk I will briefly introduce the proton spin and mass puzzles first. I will then focus on the proton charge radius puzzle, the latest experimental results, and especially the PRadexperiment at Jefferson Lab and its result.