The formation of dense groups of particles in collisions of intermediate energy nuclei

An analysis of the formation of dense groups, fluctuations, of particles is performed for central C-Cu and Mg-Mg collisions at momentum of incident nucleus, respectively, of 4.5 and 4.3 GeV/c/nucleon. To search for multiparticle dynamical correlations, the maximum density distributions and the distributions of centres of fluctuations are studied with the charged particle pseudorapidity spectra. Two peaks over statistical background are observed in the distributions of the centres of fluctuations with the structure similar to that expected from the coherent gluon radiation model and found in hadronic interactions. A charge independence of the distributions is obtained along with an azimuthal isotropy of the events containing fluctuations. The maximum density distributions are found to be generally determined by statistical contribution, although for C-Cu interactions the behaviour of these distributions shows qualitative agreement with that from the one-dimensional intermittency model. A non-poissonian character of the distributions is found in C-Cu collisions in Mg-Mg ones as well. The results obtained indicate the two different approaches, coherent vs. stochastic, to be the complementary mechanisms in the formation of the local dynamical fluctuations in multiparticle production process. The methodology used in the analysis allows the results of the present paper to be directly compared with those from other reactions. (author)