Beam energy dependence of higher moments of net-proton multiplicity distributions in heavy-ion collisions at RHIC

Abstract

We present various order moments (Variance (σ2), Skewness(S), Kurtosis(κ)) of net-proton multiplicity distributions in Au+Au collisions from the first phase of RHIC beam energy scan (√s NN=7.7-200 GeV). The measurements are carried out by the STAR detector at mid-rapidity (| y| < 0.5) and within transverse momentum range 0.4 < pT < 0.8 GeV/c. The product of moments (Sσ and κσ2) are predicted to be sensitive to the correlation length and connected to ratios of baryon number susceptibility. We observe deviations below Poisson expectations in the most central collisions for all of the energies. These results are compared with a transport model to understand the effects not related to critical physics. We also discuss the error estimation methods and the techniques to suppress centrality resolution effect in the moment analysis. © Copyright owned by the author(s).