# Quark Matter 2019 - the XXVIIIth International Conference on Ultra-relativistic Nucleus-Nucleus Collisions

3-9 November 2019
Wanda Reign Wuhan Hotel
Asia/Shanghai timezone

## Elliptic flow of electrons from heavy-flavor decays in 54.4 and 27 GeV Au+Au collisions from the STAR experiment at RHIC

4 Nov 2019, 17:40
20m
Wanda Han Show Theatre & Wanda Reign Wuhan Hotel

#### Wanda Han Show Theatre & Wanda Reign Wuhan Hotel

Poster Presentation Heavy flavor and quarkonium

### Speaker

Yuanjing Ji (University of Science and Technology of China)

### Description

Measurements of heavy-flavor hadron production and elliptic flow ($v_{2}$) provide unique and indispensable information for understanding the properties of the QGP. Recent STAR measurements indicate that in Au+Au collisions at $\sqrt{s_{\mathrm{NN}}}=$ 200 GeV $D^{0}$ mesons develop large $v_{2}$ similarly as light-favor hadrons, implying that charm quarks interact strongly with the thermalized medium at the top RHIC energy. Interestingly, at lower collision energies the electrons from heavy-flavor decays seem to exhibit much lower $v_{2}$, unlike the light-flavor hadrons. However, the precision of the previous results from STAR at $\sqrt{s_{\mathrm{NN}}}$ = 62.4 and 39 GeV did not allow for firm conclusions.

Thanks to the large data samples recorded by STAR in 2017 and 2018, we are now able to perform more precise measurements of the elliptic flow of electrons from heavy-flavor decays in Au+Au collisions at $\sqrt{s_{\mathrm{NN}}}= 54.4$ and $27$ GeV, respectively. The data sample size for each energy is more than 10 times higher than that of $\sqrt{s_{\mathrm{NN}}}= 62.4$ GeV taken in 2010. In this poster, we will present these new results from the STAR experiment on the $v_{2}$ of electrons from heavy-flavor decays, at $\sqrt{s_{\mathrm{NN}}}$ = 54.4 and 27 GeV, as a function of collision centrality and electron transverse momentum. We will also discuss physics implications of these results by comparing to theoretical model calculations.

### Primary author

Yuanjing Ji (University of Science and Technology of China)