Scaling properties of multiplicity fluctuations in heavy ion collisions simulated by AMPT model

Abstract

Three-dimensional, as well as one- and two-dimensional, studies of multiplicity fluctuation are performed using AMPT model to generate central Au-Au collision events at ${\sqrt s_{NN}}= 200$ GeV. Two- and three-dimensional normalized factorial moments in rapidity, transverse momentum and azimuthal angle are found to exhibit power-low scaling when partitioning with the same number of bins in each direction, indicating that the fluctuation are isotropic, i.e. the fractality is self-similar in multiparticle production of central Au-Au collisions. Further, we measured the parameter $ν$ which it characterizes the intermittency indices derived in particular analysis. It is found that our model result ${ν_{yϕp_t}}= 1.86{\pm}0.07$ is larger than $ν = 1.304$,which is the value of Ginzburg-Landau type of phase transition. We also explored the intermittent or fluctuational dependence on the transverse momentum. The result shows that the intermittency or fluctuation increase rapidly with the increasing of transverse momentum.