Spin-dependent Parton Distributions

We perform a global leading-order QCD fit to recent polarized structure function data in order to extract a consistent set of spin-dependent parton distributions. Assuming that there is no significant intrinsic polarization of the quark sea, the data are consistent with a modest amount of the proton's spin carried by the gluon, although the shape of the gluon distribution is not well constrained. We show how inelastic $J/\psi$ production in polarized photon-hadron scattering can, in principle, provide definitive information on the shape of the gluon distribution. (Talk presented by W.J.Stirling at the 27th International Conference on High Energy Physics, Glasgow, July 1994)