Beam-Energy and System-Size Dependence of Dynamical Net Charge Fluctuations
We present measurements of net charge fluctuations in Au+Au collisions at s(NN)=19.6, 62.4, 130, and 200 GeV, Cu+Cu collisions at s(NN)=62.4 and 200 GeV, and p+p collisions at s=200 GeV using the dynamical net charge fluctuations measure nu(+-,dyn). We observe that the dynamical fluctuations are nonzero at all energies and exhibit a modest dependence on beam energy. A weak system size dependence is also observed. We examine the collision centrality dependence of the net charge fluctuations and find that dynamical net charge fluctuations violate 1/N-ch scaling but display approximate 1/N-part scaling. We also study the azimuthal and rapidity dependence of the net charge correlation strength and observe strong dependence on the azimuthal angular range and pseudorapidity widths integrated to measure the correlation.
Grosnick, David; Koetke, Donald D.; Manweiler, Robert; Stanislaus, Shirvel; Webb, J. C.; and STAR Collaboration, "Beam-Energy and System-Size Dependence of Dynamical Net Charge Fluctuations" (2009). Physics and Astronomy Faculty Publications. 95.