Polarized structure functions in the valence quark and resonance regions and the GDH sum Original Research Article

I present in this paper the neutron spin physics program in Hall A at Jefferson Laboratory using a polarized 3He target. The program encompasses several completed experiments, in which, valuable spin observables (spin dependent structure functions) were measured in order to learn about how the nucleon spin arises from the behavior of the constituents. These experiments also offer a ground for testing our understanding of the strong regime of quantum chromodynamics (QCD) the theory of strong interactions through the determination of moments of these structure functions.