Precision Spin Structure Functions for the Proton and Deuteron with CLAS

Abstract

An extensive experimental program to measure the spin structure of the nucleon has been carried out in in Hall B at Jefferson Lab with the CEBAF Large Acceptance Spectrometer (CLAS). Using a longitudinally polarized beam scattering off longitudinally polarized NH3 and ND3 targets, the double spin asymmetry A∥ was measured over a large range in Q2 and W, providing data of impressive high precision that will give a better understanding of the structure of the nucleon in the Deep Inelastic Scattering and the valence quarks regions. Using a world data parameterization of A2 and F1, the virtual photon asymmetry A1 and the structure function g1 were extracted in a Q2 range from 0.05 to 5 GeV2 and a W range from 1.08 to 3.0 GeV. As a result of the extended kinematical range, first moments of structure functions were measured over a large range in Q2 and duality was tested. Finally, using the large kinematical overlap of different beam energies, A2 was extracted.