Measurements of Spin Structure Function G1(P) and G1(D) for Proton and Deuteron at SLAC E143

Abstract

E143 was a high precision measurement of the proton and deuteron spin structure functions g{sub 1} and g{sub 2} in SLAC's End Station A facility, with longitudinally and transversely polarized NH3 and ND3 targets, and a longitudinally polarized electron beam. The experiment was done,at beam energies of 29, 16 and 9.7 Gev. The deeply inelastic scattered electrons were detected by two independent spectrometers at 4.5{sup o} and 7{sup o} relative to the incident electron beam. At a beam energy of 29 Gev, the measurements covered the Bjorken x range from 0.03 to 0.8, and the Q{sup 2} range from 1.2 (GeV/c){sup 2} to 9.8 (GeV/c){sup 2} . It was found that the {integral}{sub 0}{sup 1} g{sub 1}{sup p}(x, Q{sub 2})dx is more than two standard deviations away from the Ellis-Jaffe sum rule, and the corresponding deuteron integral is more than three standard deviations away from the Ellis-Jaffe's rule, but the Bjorken sum rule is consistent with the experimental data. Tests of the sum rules at different values of Q{sup 2}, and the implications of these results for the quark-parton model have also been done.