Speaker
Description
The chiral magnetic wave (CMW) has been theorized to propagate in the Quark-Gluon Plasma formed in high-energy heavy-ion collisions. It could cause a finite electric quadrupole moment of the collision system, and may be observed by charge asymmetry, $A_{\rm ch}$, dependence of elliptic flow of positively and negatively charged hadrons. However, non-CMW mechanisms such as Local charge conservation (LCC) and hydrodynamics with isospin effect [1], could also contribute to the experimental observations.
In this talk, we present the STAR measurements of elliptic flow, $v_{2}$, and triangular flow, $v_{3}$, of charged pions, along with $v_{2}$ of charged kaons and protons, as a function of $A_{\rm ch}$ in Au+Au collisions at $\sqrt{s_{\rm NN}}$ = 27, 39, 62.4 and 200 GeV. The similarity between pion and kaon slopes suggests that the isospin effect is not the dominant mechanism. The slope parameters of $\Delta v_{2}$($A_{\rm ch}$) and $\Delta v_{3}$($A_{\rm ch}$) are reported and compared in different centrality and transverse momentum intervals to investigate the LCC background. The difference between the normalized $\Delta v_{2}$ and $\Delta v_{3}$ slopes, along with the measurements in small systems (p+Au and d+Au at $\sqrt{s_{\rm NN}}$ = 200 GeV), will be presented. Our data favor the CMW interpretation and disfavor the possibility that the observations result from LCC or hydrodynamics at RHIC energies.
Reference
[1] Y. Hatta, A. Monnai and B.-W. Xiao, Nucl. Phys. A947, 155 (2016).
| Content type | Experiment |
|---|---|
| Collaboration | STAR |
| Centralised submission by Collaboration | Presenter name already specified |
