Energy Dependence of Intermittency for Charged Hadrons in Au+Au Collisions at RHIC

Abstract

Density fluctuations near the QCD critical point can be probed via an intermittency analysis in relativistic heavy-ion collisions. We report the first measurement of intermittency in Au$+$Au collisions at $\sqrt{s_{{}_{\mathrm{NN}}}}$ = 7.7-200 GeV measured by the STAR experiment at the Relativistic Heavy Ion Collider (RHIC). The scaled factorial moments of identified charged hadrons are analyzed at mid-rapidity and within the transverse momentum phase space. We observe a power-law behavior of scaled factorial moments in Au$+$Au collisions and a decrease in the extracted scaling exponent ($\hat{I}½$) from peripheral to central collisions. The $\hat{I}½$ is consistent with a constant for different collisions energies in the mid-central (10-40\%) collisions. Moreover, the $\hat{I}½$ in the 0-5\% most central Au$+$Au collisions exhibits a non-monotonic energy dependence that reaches a possible minimum around $\sqrt{s_{{}_{\mathrm{NN}}}}$ = 27 GeV. The physics implications on the QCD phase structure are discussed.

8 pages, 4 figures. Published in Physics Letters B