Forward-backward multiplicity correlations caused by centrality fluctuations in high-energy heavy-ion collisions

We consider that most of the long-range forward-backward multiplicity (FB) correlations in high energy A-A collisions are caused by the centrality fluctuation, and this phenomenon interferes with the measurement of the dynamical correlations greatly. We investigate the relationship between FB correlation strength and centrality by a Monte Carlo simulation and a derivation which are tested by A MultiPhases Transport (AMPT) model in Au+Au collisions at sNN=200 GeV. We compare the FB correlation strengths of AMPT model with the results of the derivation at sNN = 7.7 to 200 GeV. A comparison between the default AMPT model and string melting AMPT model with different partonic scattering sections is made. As a result, we consider that the FB correlation strengths may be dominated by the mixing of different centrality events, and the short-range correlation may be overwhelmed for the most central collisions.