Study of Nucleon Structure and Few-Nucleon Systems using Real Photons

                           Ahmed, Mohammad (PI), North Carolina Central University, Durham, NC

The proposed research will test the predictions of theories which describe the phenomena of nucleon formation, such as protons and neutrons. These theories challenge us to measure observables which are sensitive to the structure of the nucleons at conditions which are similar to the timescale of the universe when nucleons were formed. One such set of observables are called nucleon electromagnetic polarizabilities. The polarizabilities measure the stiffness of charges and currents in nucleons to the distortion when an external electromagnetic field is applied. The proposed work will extract polarizabilities by scattering 120 MeV gamma-rays from liquid 3He and hydrogen targets and measuring their scattered angular distributions. This technique is called nuclear Compton scattering. Compton scattering from liquid 3He has never been performed before and will provide a new data set to theorists to fit the angular distributions and ultimately extract neutron polarizabilities with unprecedented level of reduction in uncertainties. Similarly, data from liquid hydrogen target will provide angular distributions which will help reduce the uncertainties in all observables in Compton scattering. These measurements will directly impact the understanding of matter formation in the universe and further provide an opportunity to us as an HBCU to prepare underrepresented minorities to contribute to the national demand of STEM education trained workforce.