Speaker
Description
Measurements of collective flow of light- and hyper-nuclei in heavy-ion collisions at high baryon density regions is important for understanding the hyper-nuclei formation mechanism.
In this talk, we will present the results on collision energy and particle mass dependence of mid-rapidity directed flow $v_1$ of hyper-nuclei ($\Lambda$, $^3_\Lambda$H, $^4_\Lambda$H) and light-nuclei (p, d, t, $^3$He, $^4$He) in mid-central Au+Au collisions at center of mass energy $\sqrt{s_{_{NN}}}$ = 3.0, 3.2, 3.5, 3.9 and 4.5 GeV. The mid-rapidity $v_1$ slope, $dv_1/dy|_{y=0}$, of hyper-nuclei shows a similar energy and particle mass dependence to that of light-nuclei and the trends can be reproduced qualitatively by calculations of a hadronic transport model plus coalescence afterburner implying that these clusters are formed in a similar way in heavy-ion collisions. In addition, we will also present the measurement of the elliptic flow ($v_2$) of light-nuclei from mid-central Au+Au collisions in the same energy range. The elliptic flow results indicate an out-of-plane expansion ($v_2 < 0$) at the lowest collision energy, whereas in-plane expansions ($v_2 > 0$) are evident at all other collision energies. These new results will be discussed within the framework of transport model calculations.
| Category | Experiment |
|---|---|
| Collaboration (if applicable) | STAR |
