Title: Measurement of the Inclusive Spin Asymmetries and the Gerasimov-Drell-Hearn Sum on and Neutron


We have measured the electron- longitudinal and transverse spin dependent inclusive cross sections through the reaction of , in the quasi-elastic and resonance regions, over a wide range of four-momentum transfer .

The longitudinally polarized electron beam of energy ranging from 0.86 to 5.1 GeV of the Thomas Jefferson National Accelerator Facility was scattered at a fixed angle of , on a high pressure (10 atmospheres) polarized target in Hall-A. The direction of the polarization of the target was maintained either parallel or perpendicular to the direction of the incident electron beam, while the polarization of the beam was reversed every second.

This measurement allows the evaluation of the generalized Gerasimov-Drell-Hearn (GDH) sum on and the neutron, and the study of its evolution as a function of . Furthermore, with results of similar measurements on the proton, the study of the Bjorken sum in the region of small will improve our understanding of the transition from perturbative QCD to non-perturbative region.