Baryon production and net-proton distributions in relativistic heavy ion collisions

The higher order moments of the net-baryon distributions in relativistic heavy ion collisions are useful probes for the QCD critical point and fluctuations. We study the net-proton distributions and their moments in a simple model which considers the baryon stopping and pair production effects in the processes. It is shown that a single emission source model can explain the experimental data well. The centrality dependence and the energy dependence of the distributions and higher moments are discussed.