Mechanisms of Forward–Backward Correlations in the Multiplicity of Particles in Ultrarelativistic Heavy-Ion Collisions

The contributions of various effects to correlations of the average multiplicity of particles emitted in the forward hemisphere of heavy-ion collisions with the multiplicity of particles emitted in the backward hemisphere (forward–backward correlations) have been comparatively analyzed. It has been shown that the experimentally observed dependence of the strength of such correlations on the centrality of lead–lead ion collisions at the Large Hadron Collider energy $$\sqrt {{{s}_{{NN}}}} $$ = 2.76 TeV can be reproduced by the HYDJET++ model if the hydrodynamic particle flow, decay of resonances, and production and suppression of high-energy quarks and gluons in hot matter are taken into account. The dominant mechanism of forward–backward correlations for the most central collisions involves the production and fragmentation of quark–gluon jets.