Model for the Q2 dependence of polarized structure functions

We present an update of a phenomenological model for the spin-dependent structure functions g1(x,Q2) of the proton and neutron. This model is based on a broken SU(6) wave function parametrized by the unpolarized structure functions. The two free parameters of the model are chosen to satisfy the Bjorken and Ellis-Jaffe sum rules. The model respects isospin symmetry and has zero strange sea polarization. Using new values for F/D from hyperon β decay the resulting Q2-dependent asymmetries A1 are in perfect agreement with the existing data. Therefore we do not see any evidence for a ''spin crisis.'' With two choices for g2 the Q2 dependence of A1(x,Q2) and A2(x,Q2) √Q2/M is predicted and shown to be small for both cases