Nucleon Structure

• Neutron elastic form factors: The precise determination of the neutron electric form factor remains a high priority goal. Experiments to achieve this over the 0.2-2.0 (GeV/c) range of momentum transfers are planned using polarized deuterium and He targets as well as neutron polarimetry. In most cases, exclusive reactions are utilized. New cross section and spin asymmetry measurements on these same targets should also provide precise low data on the magnetic form factor.

• Nucleon resonances: An extensive program is ready to explore in detail the quark-gluon structure of light quark baryons in the non- perturbative regime, as well as to test for the transition to the perturbative regime. Large acceptance detectors now under construction, and also polarized beam and target capabilities will allow many-body final states to be examined, specific nucleon resonances to be isolated, and spin structure to be determined.

• The nucleon-to-delta transition: Several experiments with real and virtual photons plan to explore further the multipole structure of this transition, which is related to the spatial deformation of these states. The quark-quark tensor interaction probed in this way is of fundamental interest.

• ``Missing" baryons and exotics: It is important to clarify the status of the ``missing" baryons predicted by the valence quark model. By looking for the non- final states which these states may favor, and using the photon as a probe, upcoming experiments may be able to complete the set of light quark baryonic states. The search for hybrid or exotic mesons can be pursued with beam energies in the 8-10 GeV range. Discovery of such states would dramatically affect our understanding of the mechanism of quark confinement.

• Parity violating electron scattering: An experiment is underway to measure the strange quark vector current contribution to the anomalous magnetic moment of the proton. It utilizes backward angle parity-violating elastic scattering from hydrogen. Other experiments are planned for the near future that will probe both the electric and magnetic strangeness distributions in the proton. In addition, quasi-elastic PV electron scattering from the deuteron is planned to constrain the weak hadronic radiative corrections to the axial form factor. This will significantly improve the determination of the strangeness contribution to the proton's magnetic moment.

• The isoscalar axial current of the proton: Neutrino scattering measurements of the isoscalar axial current for the proton at low momentum transfer have begun.

• Spin structure functions: New experiments will provide excellent spin structure function measurements for the neutron, and the first measurements of the transverse spin structure function of both the proton and neutron should become available during the next five year period. New measurements for asymmetries in semi-inclusive deep inelastic scattering will provide information on the flavor composition of the spin structure of the nucleon.

• Determination of : A new experiment will study the isospin composition of the nucleon sea through the Drell-Yan process.

• More sensitive tests of the Bjorken sum rule: New data should provide high-precision tests of the Bjorken sum rule.

• Tests of QCD using chiral perturbation theory: Many new experiments at a variety of facilities are planned to challenge and refine this theory. In particular, a major area of activity will be in spin dependent photon-nucleon scattering to test sum rules and low energy theorems.