PHASE-SPACE DEPENDENCE OF THE CORRELATIONS AMONG PARTICLES PRODUCED IN HIGH-ENERGY NUCLEAR COLLISIONS

The fluctuations of produced particles are investigated in central col lisions of proton, oxygen and sulphur projectiles with (Ag,Br) target nuclei at 200 GeV per nucleon. The analysis is carried out in terms of factorial moments and correlation integrals in different pseudorapidi ty regions. Evidence is found for nonstatistical fluctuations. These f luctuations depend weakly on the phase space, although a slightly stro nger effect is seen in the forward pseudorapidity region. The dependen ce of the observed effect on the mass of the projectile particle disag rees with the expectations of superposition models. The results of thi s analysis indicate that a self-similar cascade process is the origin of the fluctuations, even though the association of the observed effec t with the occurence of a second order phase transition cannot be defi nitely ruled out.