The spin-dependent structure function g1(x) of the deuteron from polarized deep-inelastic muon scattering

We present a new measurement of the spin-dependent structure function g1d of the deuteron from deep inelastic scattering of 190 GeV polarized muons on polarized deuterons. The results are combined with our previous measurements of g1d. A perturbative QCD evolution in next-to-leading order is used to compute g1d(x) at a constant Q2. At Q2 = 10 GeV2, we obtain a first moment Γ1d=∫1dg1ddx=0.041±0.008, a flavour-singlet axial charge of the nucleon a0 = 0.30 ± 0.08, and an axial charge of the strange quark as = −0.09 ± 0.03. Using our earlier determination of Γ1p, we obtain Γ1p − Γ1m = 0.183 ± 0.035 at Q2 = 10GeV2. This result is in agreement with the Bjorken sum rule which predicts Γ1p − Γ1n = 0.186 ± 0.002 at the same Q2.