Recoil polarization measurements of the proton electromagnetic form factor ratio at high momentum transfer.

Electromagnetic form factors are fundamental properties of the nucleon that describe the effect of its internal quark structure on the cross section and spin observables in elastic lepton-nucleon scattering. Double-polarization experiments have become the preferred technique to measure the proton and neutron electric form factors at high momentum transfers. The recently completed GEp-III experiment at the Thomas Jefferson National Accelerator Facility used the recoil polarization method to extend the knowledge of the proton electromagnetic form factor ratio G^p_E/G^p_M to Q² = 8.5 GeV². In this paper we present the preliminary results of the experiment. [ABSTRACT FROM AUTHOR]