Perdrisat Following the recent precise measurement of the ratio of the electric and magnetic form factors of the proton up to a four-momentum transfer squared of 3.5 GeV^2, in the Summer of 1998, the JLab Program Advisory Committee has approved a continuation to 5.6 GeV^2. These two form factors are directly connected to the charge and current distributions in the nucleon; they are of fundamental importance to both nuclear and particle physics. The extension of the measurement of this important ratio to large four-momentum transfers will be possible using the recoil technique as in 1998. This experiment will provide the bench mark data necessary to test future theoretical descriptions of the structure of the nucleon. The precise knowledge of charge and current distributions in the nucleon is a prerequisite for the test of any theory of the strong interaction based on QCD. Participation in several other experiments in Hall A at JLab will includestudy of polarization transfer in the photodisintegration of the deuteron and in photoduction on the proton. Likewise, polarization transfer in the transition from the proton to the delta resonance will be studied in 2000, making use of the same focal plane polarimeter developed for the program outlined above. Recent progress in the characterization of the elastic backward pd scattering reaction, based on polarization observables, has brought us close to a model independent determination of the fundamental amplitudes which describe this reaction. Two experiments using multi-GeV energy polarized deuteron and proton beams at Dubna and Cosy(Juelich) will further contribute to this study of the simplest nucleon-nucleus reaction.
