The study of forward-backward correlations between observables from separated rapidity intervals is considered as a sensitive tool for observing the collective phenomena in the ultrarelativistic collisions of hadrons and nuclei and for investigation of the initial stages of the hadronic interaction. The selection of a large gap between rapidity intervals facilitates the elimination of the short-range effects, such as jets, resonances decays, and correlated quark-antiquark pairs arizing during string decay.
In order to study the behavior of the forward-backward multiplicity and transverse momentum correlations, we calculated them in a Monte Carlo model with formation and fusion of quark-gluon strings, considering two options: with and without the resonance production and decay, provided that the mean multiplicity per rapidity stays the same. We show that the decay of the resonances causes the considerable modification of n-n and pt-pt correlations compared to the case of purely prompt particle production.
The decays have a small effect on the shape of the centrality dependence of the correlation coefficients in AA collisions but improve the agreement of string fusion model prediction with the experimental data.
The research was supported by the grant of the Russian Foundation for Basic Research (project 18-32-01055 mol_a).