nEDM R&D

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.

People

The chance is rare that all members of the group could gather together. This picture (taken in July 3, 2007) is the best one (only Yi was absent).

Gerasimov-Drell-Hearn (GDH) sum rule

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

Transversity

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

Hall-B at JLab

The CEBAF large acceptance spectrometer (CLAS) is a nearly 4π detector used to study photo- and electro-induced nuclear and hadronic reactions.

JLab

JLab's CEBAF accelerator provides continuous electron beam upto 6 GeV and there's a $310M upgrade project to double the beam energy to 12 GeV.

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, exclusive processes, exotic particle/state search
  • Fundamental symmetry study and search for new physics beyond the Standard Model
  • Development of polarized gas targets

Research Description

Our group's research focuses on understanding the structure of the nucleon and exclusive nucleon and nuclear processes at high energies in terms of quark and gluon degrees of freedom of Quantum Chromodynamics (QCD) using high energy electron and photon beams. Most of our group's work utilizes the novel experimental technique of scattering polarized electrons or photons from polarized gas targets. We have built a laser-driven polarized H internal gas target with the highest Figure-Of-Merit ever achieved for such a target. We have also built a high-pressure polarized 3He target to probe the neutron and 3He spin polarizabilities using the HIγS facility at the Duke Free Electron Laser Laboratory(DFELL). We are also embarking on a challenging experiment aiming at a two orders of magnitude improvement over the current limit on the neutron electric dipole moment (nEDM). A non-zero value of nEDM is a direct search for time-reversal symmetry violation. Such an experiment will make important contributions to the understanding of CP violation and to the search of New Physics beyond the Standard Model. We are also actively engaged in the search of exotic QCD states such as the phi-nucleon bound state, a QCD molecular state. We carry out our experiments at the Thomas Jefferson National Accelerator Facility (JLab) in Newport News, Virginia, the HIγS facility at DFELL, the Los Alamos National Laboratory and in the future at the Fundamental Neutron Beam Line at the Spallation Neutron Source, Oak Ridge National Laboratory.