Baseline for the cumulants of net-proton distributions at STAR

We present a systematic comparison between the recently measured cumulants of the net-proton distributions by STAR for 0-5% central Au + Au collisions at root S-NN = 7.7-200 GeV and two kinds of possible baseline measure, the Poisson and Binomial baselines. These baseline measures are assuming that the proton and anti-proton distributions independently follow Poisson statistics or Binomial statistics. The higher order cumulant net-proton data are observed to deviate from all the baseline measures studied at 19.6 and 27 GeV. We also compare the net-proton with net-baryon fluctuations in UrQMD and AMPT model, and convert the net-proton fluctuations to net-baryon fluctuations in AMPT model by using a set of formula. (C) 2014 Elsevier B.V. All rights reserved.