A Lattice determination of the second moment of the polarized valence quark distribution

We perform a Monte Carlo calculation of the second moment of the polarised valence quark distributions in the nucleon, using quenched Wilson fermions. The special feature of this moment is that it is directly accessible experimentally. At a scale of μ ≈ 2 GeV we find Δ (1) u = 0.198(8), Δ (1) d = −0.0477(33). We compare these numbers with recent experimental results of the SMC collaboration