Excitation Function of Net Charge Fluctuations at RHIC

Abstract

We present measurements of net charge and transverse momentum fluctuations in Au + Au collisions at ?sNN = 20, 130, and 200 GeV reported in our QM 2004 poster using measures ?+-,dyn and <?pt,1 ?pt,2>. We observe the dynamical fluctuations are finite at all three energies and exhibit a rather modest dependence on beam energy. We also find both net charge and pt fluctuations violate the trivial 1/N scaling expected for nuclear collisions consisting of independent nucleon-nucleon interactions. We speculate the observed centrality dependence arises due to radial flow and might provide insight on the width and shape of the radial flow profile.