Deep inelastic scattering of polarized electrons by polarized He-3 and the study of the neutron spin structure

The neutron longitudinal and transverse asymmetries A(1)(n) and A(2)(n) have been extracted from deep inelastic scattering of polarized electrons by a polarized He-3 target at incident energies of 19.42, 22.66, and 25.51 GeV. The measurement allows for the determination of the neutron spin structure functions g(1)(n)(x,Q(2)) and g(2)*(x,Q(2)) over the range 0.03<x<0.6 at an average Q(2) of 2 (GeV/c)(2). The data are used for the evaluation of the Ellis-Jaffe and Bjorken sum rules. The neutron spin structure function g(1)(n)(x,Q(2)) is small and negative within the range of our measurement, yielding an integral f(0.03)(0.6)g(1)(n)(x)dx = -0.028 +/- 0.006 (stat) +/- 0.006 (syst). Assuming Reggae behavior at low x, we extract Gamma(1)(n) = f(0)(1)g(1)(n)(x)dx = -0.031 +/- 0.006 (stat) +/- 0.009 (syst). Combined with previous proton integral results from SLAC experiment E143, we find Gamma(1)(p) - Gamma(1)(n) = 0.160 +/- 0.015 in agreement with the Bjorken sum rule prediction Gamma(1)(p) - Gamma(1)(n) = 0.176 +/- 0.008 at a Q(2) value of 3 (GeV/c)(2) evaluated using alpha(s) = 0.32 +/- 0.05.