Higher-moment measurements of net-kaon, net-charge and net-proton multiplicity distributions at STAR

摘要

In this paper, we report the measurements of the various moments, such as mean, standard deviation (sigma), skewness (S) and kurtosis (kappa) of the net-kaon, net-charge and net-proton multiplicity distributions at mid-rapidity in Au + Au collisions from root S-NN = 7.7 to 200 GeV with the STAR experiment at RHIC. This work has been done with the aim to locate the critical point on the QCD phase diagram. These moments and their products are related to the thermodynamic susceptibilities of conserved quantities such as net baryon number, net charge, and net strangeness as well as to the correlation length of the system which diverges in an ideal infinite thermodynamic system at the critical point. For a finite system, existing for a finite time, a non-monotonic behavior of these variables would indicate the presence of the critical point. Furthermore, we also present the moment products S sigma, K sigma(2) of net-kaon, net-charge and net-proton multiplicity distributions as a function of collision centrality and energy. The energy and the centrality dependence of higher moments and their products have been compared with different models. (C) 2014 Elsevier B.V. All rights reserved.