Elliptic flow of light nuclei and identified hadrons, their centrality and energy dependence in STAR

May 19, 2014, 3:00 PM
europium (darmstadtium)



Schlossgraben 1 64283 Darmstadt Germany
Contributed Talk Collective Dynamics Collective dynamics


Md. Rihan Haque (V)


A strongly interacting medium, namely Quark Gluon Plasma (QGP), is formed in high energy heavy ion collisions at RHIC. Elliptic flow $(v_{2})$, the second order Fourier coefficient of azimuthal distribution of the produced particles with respect to reaction plane, is used to investigate the properties of QGP. Light nuclei ($d$, $\bar{d}$, $t$, $^{\small{3}}He$), produced in such collisions, are believed to be formed by coalescence of nucleons. By comparing $v_{2}$ of light nuclei with their constituents, we can understand the production mechanism of nuclei in heavy ion collisions. At top RHIC energies, identified hadron $v_{2}$ revealed many features like the number-of-constituent quark (NCQ) scaling and mass ordering. With the combined statistics, we can test the scaling behaviors for rare multi-strange particles ($\phi$, $\Xi $ and $\Omega$). An energy dependent difference in $v_{2}$ ($\Delta v_{2}$) between particles and anti-particles was also observed in beam energy scan data at STAR. In this talk, we show the $p_{T}$ and centrality dependence of $v_{2}$ of light nuclei ($d$, $\bar{d}$, $t$, $^{3}He$), and identified hadrons ($\pi^{\pm}$, $K^{\pm}$, $K_{s}^{0}$, $p$, $\bar{p}$, $\phi$, $\Lambda$, $\bar{\Lambda}$, $\Xi^{\pm}$, $\Omega^{\pm}$) at mid-rapidity for Au+Au collisions at $\sqrt{s_{NN}}\ =\ 7.7,\ 11.5,\ 19.6,\ 27,\ 39,\ 62.4$ and $200$ GeV from STAR. Light nuclei and hadrons are identified using the time projection chamber and time-of-flight detector systems of STAR. The mass number and constituent quark scaling of nuclei $v_{2}$ will be presented. Light nuclei $v_{2}$ will be compared to those from $p$($\bar{p}$) and to a coalescence model calculation using the phase space distributions of produced nucleons in a transport model. The centrality dependence of $\Delta v_{2}$ for identified hadron will be shown and compared to model calculations. We further discuss NCQ scaling and mass ordering of multi-strange hadron $v_{2}$ at the top energy Au+Au collisions at RHIC.
On behalf of collaboration: STAR

Primary author

Md. Rihan Haque (V)

Presentation materials