IMPORTANCE OF GLUON-GLUON AND QUARK-ANTIQUARK CONTRIBUTIONS TO CHARMONIUM PRODUCTION IN PROTON-PROTON AND ANTIPROTON-PROTON COUISIONS

The importance of the gluon-gluon and quark-antiquark contributions to the production of charmonium states in proton-proton and antiproton-p roton collisions is determined within the parton model in a way which does not rely on any assumption on the dynamics (leading diagrams, col or neutralisation mechanism,...). It is shown that the combined analys is of total and differential inclusive J/psi, production cross-section s for both systems allows such a determination. The primordial contrib utions are also extracted at one energy. The implications of the numer ical values are also discussed.