Measurements of the elastic electromagnetic form factor ratio μpGEp/GMp via polarization transfer -: art. no. 038202

We present measurements of the ratio of the proton elastic electromagnetic form factors, mu (p)G(Ep)/G(Mp). The Jefferson Lab Hall A Focal Plane Polarimeter was used to determine the longitudinal and transverse components of the recoil proton polarization in ep elastic scattering; the ratio of these polarization components is proportional to the ratio of the two for-in factors. These data reproduce the observation of Jones et al. [Phys, Rev. Lett. 84, 1398 (2000)], that the form factor ratio decreases significantly from unity above Q(2) = 1 GeV2.