Experimental Studies of the 3D Structure of Nucleons and Nuclei

About This Grant

The aim of this research program is to study the 3D structure of atomic nuclei and their constituents (protons and neutrons) to unravel the mysteries of the strong nuclear force that binds them and generates their mass. This work will address several key topics in the 2023 NSAC long-range plan for nuclear science. To achieve these goals, the program will use world-leading electron-scattering facilities at Jefferson Lab (JLab) in Virginia. By combining the excitement of cutting-edge discovery science with a direct path to applications in energy, medicine, and defense, this program also contributes to recruitment of the next generation into STEM and workforce development that can directly affect the economy and everyday lives. The program will focus on the study of exclusive lepton-antilepton production using the framework of generalized parton distributions. Here, Compton scattering is sensitive to the distribution of quarks while quarkonium (e.g., J/psi) production is sensitive to gluons – the force carriers of the strong interaction. The PI and the postdoc will complete the analysis of the first-ever measurement of time-like Compton scattering on the proton (JLab experiment E12-12-001), and prepare for measurements of such processes at the EIC, providing essential input for future detector development. The PI and the graduate student will use JLab data to establish the feasibility of a similar measurement on the neutron, which would provide complementary information. If the results are promising, the analysis will lead to the first-ever publication on this process. The PI and the undergraduate students will carry out a series of projects aimed at the study of J/psi production on protons and nuclei at the EIC, which will for the first time make it possible to directly map out the gluon field. Measuring both Compton scattering and J/psi production will make it possible to compare the distributions of quarks and gluons (matter and force), while a comparison of J/psi production on the free and bound proton, as well as a nucleus as a whole, can tell us how the strong interaction is modified inside a nucleus. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.