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A theoretical description of long-range correlations between observables measured in separated rapidity intervals for nucleus-nucleus collisions at high energies is given. With allowance for an actual distribution of nucleons in nuclei, the p t n and nn correlation functions and respective correlation coefficients are calculated at various values of the impact parameter. It is shown that fluctuations of the impact parameter at a level of 1 fm, which are irremovable in experiments, affect the correlation coefficients substantially. It is shown that p t n correlations become much more pronounced upon going over from the SPS to the RHIC and LHC energies. The p t n and nn correlation functions calculated for the minimumbias case (that is, without selection in centrality) are compared with experimental data on PbPb collisions at the SPS energies. [ABSTRACT FROM AUTHOR]

A theoretical description of long-range correlations between observables measured in separated rapidity intervals is given. It is shown that, in contrast to two-particle correlations—specifically, correlations between the transverse momenta of charged particles produced in different rapidity intervals—the correlations between the average transverse momenta of all particles in an event that are produced in two rapidity intervals do not tend to zero with increasing number of strings. The energy dependence of the correlations is analyzed. At a fixed degree of collision centrality, the correlations are found to grow upon going over from the SPS energy to the RHIC and LHC energies; they are compared with correlations of the p t n type. Correlation functions calculated for the minimum-bias case (that is, without any selection in the degree of collision centrality) are contrasted against relevant experimental data on PbPb collisions at the SPS energies. [ABSTRACT FROM AUTHOR]

Long range multiplicity-multiplicity, pT2-multiplicity and p2T- p2T correlations are studied in the percolating color string picture under different assumptions of the dynamics of the string interaction. It is found that the strength of these correlations is rather insensitive to these assumptions; nor is it sensitive to the geometry of the fused string clusters that formed, the percolation phase transition in particular. Both multiplicity-multiplicity and pT2-multiplicity correlations are found to scale and depend only on the string density. pT2-multiplicity correlations, which are absent in the independent string picture, are found to be of the order of 10% for central heavy ion collisions and can serve as a clear signature of string fusion. In contrast p2T- p2T correlations turned out to be inversely proportional to the number of strings and therefore to be very small for realistic collisions. [ABSTRACT FROM AUTHOR]