Research Interests: Experimental Nuclear Physics

My research is focused on precision measurement of fundamental properties of nucleons. These studies seek to understand the internal structure of hadrons in terms of the underlying quark and gluon degrees of freedom of Quantum Chromodynamics (QCD). Most of this research is carried out at Jefferson Lab (JLab) in Newport News where we undertake experiments in search of signatures of QCD in nuclei. Recently, we completed the PRad experiment which aims to measure the proton charge radius with sub-percent precision. The PRad experiment may help resolve the large discrepancy between measurements using electrons vs muons ( the so called proton radius puzzle ). Another recently approved experiment involves measuring the mesonic content of the nucleon using deep-inelastic scattering with spectator tagging, this experiment will also allow us to exact the quark distributions inside pions.

My research program also includes precision tests of fundamental symmetries and the Standard Model, which constitute experimental searches for new forces beyond the four included in the Standard Model. One of these experiments (The QWeak experiment) used parity violating electron scattering from the proton to perform the first high precision measurement of the weak charge of the proton. As part of this experiment my group built a set of diamond micro-strip tracking detectors which were the first such detectors to be used in a nuclear and particle physics experiment.

Another experiment is the new search for the neutron electric dipole moment (The nEDM Experiment) which is proposed for the Spallation Neutron Source at Oak Ridge National Lab. The goal of this experiment is a factor of 100 improvement over the current experimental limit. This search for a non-zero value of the neutron EDM is a direct search for violation of the time reversal symmetry (T).  

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