Ω and φ in Au ＋ Au collisions at （s（NN））^1/2= 200 and 11.5 GeV from a multiphase transport model

Within the framework of a multiphase transport model, we study the production and properties of Ω andφ in Au ＋ Au collisions with a new set of parameters for （s（NN））^（1/2）= 200 GeV and with the original set of parameters for （s（NN））^（1/2）= 11.5 GeV. The AMPT model with string melting provides a reasonable description at （s（NN））^（1/2）= 200 GeV,while the default AMPT model describes the data well at （s（NN））^（1/2）= 11.5 GeV. This indicates that the system created at top RHIC energy is dominated by partonic interactions, while hadronic interactions become important at lower beam energy, such as （s（NN））^（1/2）= 11.5 GeV. The comparison of N（Ω^＋＋Ω^-）/[2N（φ）] ratio between data and calculations further supports the argument. Our calculations can generally describe the data of nuclear modification factor as well as elliptic flow.