Color-octet contributions toJψhadroproduction at fixed target energies

We investigate the integrated cross section for forward $\frac{J}{\psi }$ production in proton-proton and pion-proton collisions at center-of-mass energies up to 60 GeV. We find that color-octet contributions to the cross section are crucially important, and their inclusion produces a very good description of the data. Since the values of nonperturbative matrix elements are fixed by other experiments, these predictions are parameter-free.