CAREER: Unravelling the Strong Interaction with High-Energy Nuclear Scattering

Atomic nuclei make up close to 100% of visible matter around us. Even though it is known that nuclei are bound by the underlying fundamental theory of the strong nuclear interaction, it is not yet understood how exactly they (and the nucleons within them) emerge from it. This project studies and advances our knowledge of the strong interaction through the theoretical modeling of high-energy reactions with light nuclei. These reactions probe the quark and gluon substructure of the light nuclei and give access to measurements (and corresponding calculations) which are not possible on a free proton. Light nuclei consist of only a few protons and neutrons, resulting in reactions with a high degree of precision and control, combined with the ability to study the effect of the nuclear medium on the quark and gluon structure. The PI mentors graduate students working on the research at a minority serving institution and engages in outreach activities involving high-school teachers and the local science museum. In an effort to integrate education and research, the PI will also develop nuclear physics-themed modules to be used at STEM summer camps for local high school students. The goal of this project is to advance our theoretical understanding of non-perturbative aspects of the strong interaction, mainly through electron scattering off light nuclei. In high-energy reactions, an electron probes the nucleus as if sitting on a wave front moving at the speed of light. Hence the PI and his students will use the framework of light-front quantum mechanics, which enables to cleanly separate the low-energy nuclear structure of the light nucleus from the high-energy reaction dynamics. Light nuclei offer unique features to probe the strong interaction: they can be polarized, enabling spin-dependent studies; the initial nuclear state is theoretically and experimentally well known and can be controlled in measurements by detecting nuclear breakup. For this project, the team will exploit these features in specific reactions on the deuteron and helium. For polarized nuclei the team will study applications of a newly developed algorithm which generalizes the spin-1/2 Dirac algebra to higher spin cases. These studies are of importance for current and future measurements at US-based accelerator facilities such as Jefferson Lab and the future electron-ion collider at Brookhaven National Lab. 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.