Speaker
Dr
Shusu Shi
(the STAR collaboration)
Description
We present a systematic study of the transverse momentum ($p_T$), rapidity and centrality dependence of elliptic flow, $v_2$, using several methods in Au + Au collisions at $\sqrt{s_{NN}}$ = 7.7, 11.5 and 39 GeV. The difference between $v_2$ using event plane from detectors separated in rapidity ($v_2${2}) and four particle cumulants ($v_2${4}) seems to decrease as the beam energy decreases. The implications of this result towards understanding the energy dependence of non-flow and flow fluctuations will be discussed. The energy dependence of $v_2$ will be presented by a comparison with results from high energies at RHIC ($\sqrt{s_{NN}}$ = 62.4 and 200 GeV), at LHC ($\sqrt{s_{NN}} $ = 2.76 TeV) and similar energy at SPS ($\sqrt{s_{NN}}$ = 7.6 GeV). We observe the $v_2$($p_T$) are very comparable (~10\%) at mid-rapidity and $p_T$ > 0.5 GeV/c beyond $\sqrt{s_{NN}}$ = 39 GeV. We will also compare our results to transport model calculations, such as those from UrQMD model, AMPT default model and AMPT string-melting model with different parton cross sections.
Primary author
Dr
Shusu Shi
(the STAR collaboration)
