Quark and gluon production in high energy nucleus-nucleus collisions

The transverse energy spectrum dσ/dET in very high energy nucleus-nucleus collisions is considered by including both hard and soft processes. The production of hard gluons and quarks is computed in perturbative QCD and the soft component is taken from the recent CERN heavy ion experiments. We conclude that while hard processes carry less than 5% of the total ET at the energies √s=20 GeV of the CERN experiments, their share grows rapidly with energy so that it is about a half at RHIC energies, √s=200 GeV, and clearly dominant at Tevatron energies, √s=2000 Gev. (orig.)