Analysis of the neutron spin structure function g1n by using the Laplace transform technique

In this paper, the polarized neutron structure function [Formula: see text] in the [Formula: see text] nucleus is investigated and an analytical solution based on the Laplace transform method for [Formula: see text] is presented. It is shown that the neutron spin structure function can be extracted directly from the polarized nuclear structure function of [Formula: see text]. The nuclear corrections due to the Fermi motion of the nucleons as well as the binding energy considerations are taken into account within the framework of the convolution approach and the polarized structure function of [Formula: see text] nucleus is expressed in terms of the spin structure functions of nucleons and the light-cone momentum distribution of the constituent nucleons. Then, the numerical results for [Formula: see text] are compared with experimental data of the SMC and HERMES collaborations. We found that there is an overall good agreement between the theory and experiments.

Compass Measurement of g1 and QCD Fits

We present the latest COMPASS results on the proton spin structure function g[Formula: see text](x) at 200[Formula: see text]GeV. The data improve the statistical precision by a factor of [Formula: see text]2 at low x. A reevaluation of the Bjorken sum rule based on COMPASS proton and deuteron data confirms its validation to a 9% accuracy. Finally, results from a global NLO QCD fit of g1 world data are shown. The extracted spin singlet distribution leads to an integrated value of [Formula: see text] at Q[Formula: see text] (GeV/c)2. The large uncertainty is mainly driven by the unknown shape of the distribution.