Gold plated ultra-pure copper is used to provide thermal contact from the dilution refrigerator to the grooved acrylic cell. Pyrex injection cell is one important part of the nEDM experiment.


MEPG group members (from left to right): Georgios Laskaris, Pinghan Chu, Yang Zhang, Xiaqing Li, Qiujian Ye, Haiyan Gao, Chao Peng, Min Huang, Mehdi Meziane, Xuefei Yan, Sucheta Jawalkar

Gerasimov-Drell-Hearn (GDH) sum rule

The GDH sum rule provides an elegant connection between the nucleon excitation spectrum and its static properties.


Neutron TRANSVERSITY experiment will study nucleon transverse spin structure together with other transverse momentum dependent structure functions (TMDs).

Proton Charge Radius

The proton charge radius (PRad) experiment in Hall B at Jefferson Lab.


JLab's CEBAF accelerator provides continuous electron beam up to 12 GeV after the upgrade with four experimental halls.

Hall-A at JLab

The two High Resolution Spectrometers (HRS) in Hall-A are designed for detailed investigation of nuclear structure.

Injection Test

Test the polarization loss of 3He injected from the ABS and collected within superfluid 4He at 0.3 - 0.5K. Very important part of the new nEDM experiment.

Relaxation time

3He relaxation time measurement from dTPB coated acrylic cell at 1.9K and 0.3 - 0.5K.

Duke FEL Lab

The storage ring based FEL provides precisely tunable coherent radiation and a novel light source (Hiγs) with unprecedented photon flux by internal backscattering.

Areas of Interest

    QCD Physics: nucleon structure, exotic particle/state search; Fundamental symmetry study and search for new physics beyond the Standard Model; Development of polarized gas targets

Research Overview

Our research focuses on understanding the structure of the nucleon in terms of quark and gluon degrees of freedom of Quantum Chromodynamics (QCD), search for QCD exotics, and fundamental symmetry studies at low energy to search for new physics beyond the Standard Model of electroweak interactions. Most recently, our studies of the structure of the nucleon have been focusing on a precision measurement of the proton (see our 2019 Nature paper on this topic) and deuteron charge radii to elucidate on the proton and the deuteron charge radius puzzles, and on imaging the three-dimensional structure of the nucleon in momentum space through the extraction of transverse momentum dependent parton distribution functions (TMDs), employing polarized semi-inclusive deep inelastic scattering processes. The nucleon tomography provided by TMDs will uncover the rich QCD dynamics, and provide quantitative information about the quark orbital angular momentum contribution to the proton spin. TMDs will also provide information on fundamental quantities such as the tensor charge of the nucleon, a quantity not only important for testing lattice QCD predictions, but also important for searches of new physics beyond the Standard Model together with the next generation of nucleon electric dipole moment experiments. Our group is playing leading roles in the Solenoidal Large Intensity Device (SoLID) project at Jefferson Lab, a high profile program which will make major impact on TMD physics, the QCD trace anomaly contribution to the proton mass through precision measurement of J/psi production near threshold, and search for new physics beyond the Standard Model using parity-violating deep inelastic scattering. Most of our work utilizes the novel experimental technique of scattering polarized electrons or photons from polarized gas targets. Our group built a number of state-of-the-art polarized gas targets over the years including H/D internal gas target and a high-pressure polarized 3He target for photon experiments using the High Intensity Gamma Source (HIGS) facility . Our research is being carried out mostly at the Thomas Jefferson National Accelerator Facility (JLab) in Newport News, Virginia, and the HIGS facility located on the campus of the Duke University.