An important goal of nuclear physics is to come to a fundamental understanding of the structure of the constituents of nuclear matter, protons and neutrons. Electron scattering is a superb tool to study the internal structure of nucleons as the resolving power of the probe can be varied. One of the missions of Jefferson Lab is to study the structure of nucleons in a large range, from several fm (1 fm = 10^-13 cm) down to less than 1/10 fm. The structure of protons and neutrons have been studied in deep inelastic experiments at very small distances, however little is known about the transition region where the theory of strong interactions, QCD, is very difficult to solve, and approximations are necessary. Precise experiments on the electromagnetic properties of nucleons and their excited states are essential to make progress. The CLAS detector at Jefferson Lab is a new and powerful tool to address these fundamental problems. CLAS has been used to measure exclusive processes to study resonance transitions, to search for "missing" resonances, and to measure nucleon spin structure functions. Recent results from these measurements will be presented and connections between the deep inelastic regime and the resonance region will be discussed.

ANL Physics Division Colloquium Schedule