Tests of the polarized gluon content of the proton

Within the framework of perturbative QCD, two processes are considered: heavy flavor production (of open $Q bar Q,Q$ = c or b, and of heavy quarkonia) and large-$p sb{ Upsilon}$ direct photon production--both in proton-proton collisions with polarized beam and target. For the first process, the differential and total cross sections for the subprocesses $ vec g vec g to Q bar Q$ and $ vec q vec{ bar q} to Q bar Q$ are determined to order $ alpha sbsp{s}{2}$. For both processes, asymmetries are computed using two sets of polarized parton distributions differing in the magnitude of the gluon distribution. It is shown that, for both processes, experiment can well distinguish between a large and a small polarized gluon distribution