Sivers asymmetry for the proton and the neutron

A formalism is presented to evaluate the Sivers function in constituent quark models. A non‐relativistic reduction of the scheme is performed and applied to the Isgur‐Karl model. The results obtained are consistent with a sizable Sivers effect and the signs for the u and d flavor contributions turn out to be opposite. The Burkardt Sum Rule is fulfilled to a large extent. After the estimate of the QCD evolution of the results from the momentum scale of the model to the experimental one, a reasonable agreement with the available data is obtained. A calculation of nuclear effects in the extraction of neutron single spin asymmetries in semi‐inclusive deep inelastic scattering off 3He is also described. In the kinematics of forth‐coming experiments at JLab, it is found that the nuclear effects arising within an Impulse Approximation approach are under control.