Generalized GDH sum and spin structure of 3He and neutron

The generalized GDH sum rule allows a systematic study of the spin structure of the nucleon over a variety of scales, ranging from nucleon degrees of freedom at Q(2) = 0 to quark degrees of freedom at large Q(2). With existing measurements for both large Q(2) and real photons, interest has turned to the transition region between nucleon and quark degrees of freedom, for which no data exist. The Jefferson Lab E94-010 Collaboration has recently completed an experiment studying He-3((e) over right arrow, e ') for the transition region, Q(2) approximate to 0.1 to 1.0 GeV2. Missing mass coverage ranges from the elastic peak to deep inelastic scattering. The data allow extraction of the 3He and neutron spin structure functions, and of the generalized Gerasimov-Drell-Hearn (GDH) sum.