Double-spin asymmetries in electron-nucleon scattering in Halls B and C at JLab

Abstract

Three experiments at JLab have measured the double polarization asymmetries $A_{\Vert}(x, Q^{2}$ ) in the nucleon resonance region, using polarized electron beams incident on polarized proton and deuteron targets. The analysis for the first experiment, eg1a in Hall B, is nearly finished and preliminary values of the spin structure function g 1(x, Q 2) and the first moment $\Gamma_{1}$ (x) have been extracted. The other two experiments, one in Hall B and one in Hall C, are still analysing data. Some results are presented.