Measurement of density correlations in pseudorapidity via charged particle multiplicity fluctuations in Au+Au collisions at VsNN=200 GeV

Abstract

Longitudinal density correlations of produced matter in Au+Au collisions at VsNN=200 GeV have been measured from the inclusive charged particle distributions as a function of pseudorapidity window sizes. The extracted αξ parameter, related to the susceptibility of the density fluctuations in the long-wavelength limit, exhibits a nonmonotonic behavior as a function of the number of participant nucleons, Npart. A local maximum is seen at Npart~90, with corresponding energy density based on the Bjorken picture of εBjτ~2.4 GeV/(fm2c) with a transverse area size of 60 fm2. This behavior may suggest a critical phase boundary based on the Ginzburg-Landau framework.