Event selection criteria in nucleus-nucleus collisions

Several event selection criteria in ultrarelativistic nucleus-nucleus collisions are analysed in the framework of the dual parton model. First, central and semicentral collisions are compared. We conclude that semicentral processes are more appropriate to observe high energy density events, where the formation of a quark-gluon plasma could take place. Secondly, the dependence of the achieved energy density on the degree of centrality of the collision is studied. We analyse the implications of our results for future experiments at CERN.