In heavy-ion ({it A-A}) collisions, the correlations among the particles produced across wide range in rapidity, probe the early stages of the reaction. The analyses of forward-backward multiplicity correlations in these collisions are complicated by several effects, which are absent or minimized in hadron-hadron collisions. This includes effects, such as the centrality selection in the {it A-A} collisions, which interfere with the measurement of the dynamical correlations. A method, which takes into account the fluctuations in centrality selection, has been utilized to determine the forward-backward correlation strength {$b_{rm corr}$} in {itA-A} collisions. This method has been validated by using the HIJING event generator in case of Au-Au collisions at $sqrt{s_{NN}}$= 200 GeV and Pb-Pb collisions at $sqrt{s_{NN}}$= 2.76 TeV. It is shown that the effect of impact parameter fluctuations is to be considered properly in order to obtain meaningful results.
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