The nucleon elastic form factors are important inputs to our understanding of the nucleon structure and hadronic physics. However, in the region Q^2>2~(GeV/c)^2 there is a large discrepancy between data on the proton G_E^p/G_M^p ratio obtained using two different techniques - Rosenbluth separation and polarization transfer. Although recently it has been shown that the two-photon exchange (TPE) might be the solution, a full understanding of TPE has not been achieved. Whether it fully explains the discrepancy in the large Q^2 region and whether there are other mechanisms that may cause the discrepancy are still unknown. We present here a different approach aimed at understanding the G_E^p/G_M^p data. We plan to measure the asymmetry of elastic ep scattering using a polarized beam and a polarized proton target, from which G_E^p/G_M^p up to Q^2=5.6~(GeV/c)^2 will be extracted using the formalism of double polarization asymmetries. A proposal has been submitted to JLab PAC-26. The experimental setup and the expected uncertainties will be presented. This work is supported by the U.S. Department of Energy, Office of Nuclear Physics, under contract No. W-31-109-ENG-38.
Presentation type: Oral
Sorting category: 13b. Mini-symposium B: Two Photon Physics in Electron Scattering
Submitter: Xiaochao Zheng
Submitting Member ID: 60057843
submitting member email address: xiaochao@jlab.org
Submitting Member affiliation: Argonne National Lab
CategoryType: E
Email address[1]: xiaochao@jlab.org
Author note[1]: mailing address: 12000 Jefferson Avenue, Newport News, VA 23606
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