Baseline study for higher moments of net-charge distributions at energies available at the BNL Relativistic Heavy Ion Collider

Nihar R. Sahoo, Sudipan De, and Tapan K. Nayak

Phys. Rev. C 87, 044906 – Published 17 April 2013

Abstract

Lattice QCD models predict the presence of a critical point in the QCD phase diagram where the first-order phase transition from a system of quark-gluon plasma to hadron gas ceases to exist. Higher moments of conserved quantities, such as net-charge, net-baryon number, and net-strangeness, are proposed to be sensitive probes for locating the critical point. The moments of net-charge distributions have been studied as a function of centrality for Au+Au collisions at $\sqrt{s_{N N}} = 7.7$ to 200 GeV using three event generators, viz., UrQMD, HIJING, and THERMINATOR-2. The effect of centrality selection, resonance production, as well as contributions from particle species to the net-charge moments and their products have been studied. It is observed that mean of the net-charge distributions are dominated by net-protons, whereas standard deviation, skewness, and kurtosis closely follow net-pion distributions. These results, along with the predictions from the hadron resonance gas model, are presented.