Speaker
Description
The first harmonic coefficient of the Fourier expansion of the final-state momentum-space azimuthal distribution of produced particles is called directed flow ($v_{1}$). It describes the collective sideward motion of emitted particles. $v_{1}$ is sensitive to the equation of state of nuclear matter, making it a useful probe for studying the phase transition. Results from the RHIC Beam Energy Scan-I (BES-I) program on directed flow shows that the proton and net-proton slope parameter $\frac{dv_{1}}{dy}|_{y=0}$ exhibits a minimum between 11.5 and 19.6 GeV. Additionally, the net-proton $\frac{dv_{1}}{dy}|_{y=0}$ changes sign twice between 7.7 and 39 GeV.
In this poster, we will present measurements of the directed flow of $\pi^{+}$,$\pi^{-}$,$K^{+}$,$K^{-}$ and $K_s^{0}$ in Au+Au collisions at $\sqrt{s_{NN}}$ = 7.7, 9.2, 11.5, 14.6, and 19.6 GeV from the RHIC Beam Energy Scan-II (BES-II) program. The rapidity and centrality dependence of $v_{1}$, as well as the energy dependence of the $v_{1}$ slope, will be discussed. These results will also be compared with predictions from the ultra-relativistic quantum molecular dynamics (UrQMD) model.
| Category | Experiment |
|---|---|
| Collaboration (if applicable) | STAR |
