UVA-phys-Zheng

Professor Zheng’s group conducts research at the Thomas Jefferson National Accelerator Facility (www.jlab.org, or see a short and cool video here). Our research interest includes study of the nucleon structure, with a focus on the spin structure of the nucleon measured using polarized beams and polarized targets. The nucleon structure is determined by how quarks and gluons interact with each other, thus such information could reveal some fundamental properties of the strong interaction and QCD. Experiments that studied this topic include previous 6 GeV A1n and EG4 experiments, the 12 GeV A1n experiment that was completed in year 2020, and the recently completed CLAS12 A1p (RGC) experiment. Another major aspect of our research is testing the Standard Model of Particle Physics by measuring parity violation (PV) in electron deep inelastic scattering (DIS) (see this Nature article on the subject (2014), or for a lighter reading see Dr. Marciano’s “Quarks are not ambidextrous“). By measuring the PVDIS asymmetry off a hydrogen and a deuterium target, one can access important coupling constants of the Standard Model and study many interesting hadronic effects such as charge symmetry violation and the asymmetry in the sea quark distribution inside the nucleon. Looking forward, future projects that focus on this direction include PVDIS using the upcoming mid-scale equipment project called SoLID and the future electron-ion collider (EIC), The SoLID, if combined with a future positron beam at JLab, also offers the possibility of measuring a new electron-quark effective coupling that was never measured before.