  Using a sample of >10^5 J/psi to mu+mu- decays, Fermilab experiment 789 has
studied production of J/psi and psi-prime in 800-GeV proton-nucleon collisions.
Differential cross sections and nuclear dependences have been measured for
charmonium as well as for charm and beauty production. While charm and beauty
production are consistent with perturbative QCD calculations, charmonium cross
sections exceed the predictions of the color-singlet model by large factors,
suggesting that additional mechanisms (such as color-octet production) may play
important roles. Nuclear dependences of production cross sections may offer a
new tool for the detailed understanding of charmonium production.
