Elliptic Flow of charged particles in Au+Au collisions at $\sqrt{s_{NN}}$ = 7.7, 11.5 and 39 GeV from STAR

Not scheduled
Théâtre National (Centre Bonlieu)

Théâtre National

Centre Bonlieu

Board: 19
Poster Global and collective dynamics


Dr Michael K. Mitrovski (for the STAR collaboration)


The study of elliptic flow and non-flow effects over a wide energy range can provide information on the onset of collective effects in heavy-ion collisions. In 2010, STAR collected high statistics data samples at lower RHIC energies at $\sqrt{s_{NN}}$ = 7.7, 11.5 and 39 GeV. We will present measurements of charged particle elliptic flow using the event-plane ($v_{2}\{EP\}$) determined from detectors separated in $eta$, 2-particle ($v_{2}\{2\}$) and 4-particle ($v_{2}\{4\}$) correlation methods integrated over $p_{t}$ and $\eta$ along with differential elliptic flow $v_{2}(p_{t})$ and $v_{2}(\eta)$. The difference using $v_{2}\{EP\}$, $v_{2}\{2\}$ and $v_{2}\{4\}$ decreases with decreasing the beam energy. In addition we observe that no large differences ($\sim$10\%) are visible for the $p_{t}$ dependence ($\mid\eta\mid$ $<$ 1.0 and $p_{t}$ $>$ 0.5) of $v_{2}\{4\}$ starting from $\sqrt{s_{NN}}$ = 39 GeV. A change of the energy dependence is observed in the difference between $v_{2}\{2\}^{2}$ and $v_{2}\{4\}^{2}$ which is related to $v_{2}$ fluctuations ($\sigma_{v_{2}}$) and non-flow correlations ($\delta_{2}$). The measurements will be compared to measurements at SPS, higher RHIC and LHC energies, as well as string hadronic/partonic and hydrodynamic model calculations.

Primary author

Dr Michael K. Mitrovski (for the STAR collaboration)

Presentation materials

There are no materials yet.