Correlations between multiplicities and average transverse momentum in the percolating colour strings approach

Abstract

Long range correlations multiplicity-multiplicity, $p_T^2$-multiplicity and $p^2 - p^2_T$ are studied in the percolating colour string picture under different assumptions of the dynamics of string interaction. It is found that the strength of these correlations is rather insensitive to these assumptions nor to the geometry of formed fused string clusters. Both multiplicity-multiplicity and $p_T^2$-multiplicity correlations are found to scale and depend only on the string density. The $p_T^2$-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 the $p^2_T - p^2_T$ correlations turned out to be inversely proportional to the number of strings and so very small for relaistic collisions.