Energy and System-Size Dependence of Long-Range Multiplicity Correlations from the STAR Experiment

Abstract

A discussion of results for short and long-range multiplicity correlations (forward-backward) are presented for several systems (Au+Au, Cu+Cu, and pp) and energies (e.g. $\sqrt{s_{NN}}$ = 200, 62.4, and $\approx$ 20 GeV). These correlations are measured with increasing values of a gap in pseudorapidity, from no gap at midrapidity to a separation of 1.6 units ($|\eta|$ = 0.8). For the highest energy, central A+A collisions, the forward-backward correlation strength maintains a constant value across the measurement region. In peripheral collisions, at lower energies, and in pp data, the maximum appears at midrapidity. This result may indicate the possible formation of high density matter for central A+A collisions at $\sqrt{s_{NN}}$ = 200 GeV.