Oxygen and sulfur nuclei with energies of 200 GeV/nucleon have been allowed to interact in nuclear emulsions exposed at CERN. These emulsions have been scanned with a minimum bias so that essentially all the interactions occurring were detected. Nearly 1000 interactions of each projectile have been analyzed. We present results on the multiplicity distributions, the pseudorapidity distributions, and the fragmentation of the projectile and target nuclei. It is shown that the mean number of intranuclear collisions in each interaction, calculated from a superposition model, provides a useful parameter for organizing the data. We conclude that there are no significant deviations even at these energies from models, such as the VENUS model, describing the interactions as being the superposition of individual nucleon-nucleon collisions. PACS number(s): 25.75.+r, 12.40.Aa, 13.85.Hd, 25.40.Ve
The concept of factorial moments was applied to an analysis of the dynamical fluctuations in the charge distributions of the fragments emitted from gold nuclei with energies 10.6 and Ͻ1.0 GeV/nucleon interacting with emulsion nuclei. Clear evidence for intermittent fluctuations has been found in an analysis using all the particles released from the gold projectile, with a stronger effect observed below 1 GeV/nucleon than at 10.6 GeV/nucleon. For the full data sets, however, the intermittency effect was found to be very sensitive to the singly charged particles, and neglecting these particles strongly reduces the intermittency signal. When the analysis is restricted to the multiply charged fragments, an intermittency effect is revealed only for multifragmentation events, although one that is enhanced as compared to the analysis of all, singly and multiply charged, particles. The properties of the anomalous fractal dimensions suggest a sequential decay mechanism, rather than the existence of possible critical behavior in the process of nuclear fragmentation. The likely influence of the charge conservation effects and the finite size of decaying systems on the observed intermittency signals was pointed out.
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