Omega and phi in Au plus Au collisions at root S-NN=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 Omega and phi in Au + Au collisions with a new set of parameters for root(NN)-N-S = 200 GeV and with the original set of parameters for root(NN)-N-S = 11.5 GeV. The AMPT model with string melting provides a reasonable description at root(NN)-N-S = 200 GeV, while the default AMPT model describes the data well at root(NN)-N-S = 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 root(NN)-N-S = 11.5 GeV. The comparison of N (Omega(+)Omega(-))/[2N(phi)] 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.