The 8th Asian Triangle Heavy-Ion Conference (ATHIC2021)

The hypertriton and hyperquadron directed flow measurements in √sNN = 3 GeV Au+Au collisions from STAR

8 Nov 2021, 11:25

17m

Room 107 (60th Anniversary Hall , Inha Univ. Incheon, South Korea)

Experiment Contributed Session 5

Speaker

Dr Yapeng Zhang (Institute of Modern Physics, CAS)

Description

Collective flow has been commonly used for studying the properties of matter created in high-energy heavy-ion collisions, due to its high sensitivity on early stage collision dynamics. The first-order Fourier coefficient of azimuthal distributions of produced particles $v_1$, also called directed flow, has been analyzed for different particle species from the lightest mesons to light nuclei in such collisions. In this talk, we report ${}_{\mathrm{\Lambda }}^3$H reconstruction from its two-body and three-body pionic decay channels, and ${}_{\mathrm{\Lambda }}^4$H reconstruction from its two-body pionic decay channel. Then, the first observation of the hyper-nuclei ${}_{\mathrm{\Lambda }}^3$H and ${}_{\mathrm{\Lambda }}^4$H directed flow $v_1$ from $\sqrt{s_{NN}}=$ 3 GeV mid-central (5–40%) Au+Au collisions at RHIC will be presented. The directed flow of ${}_{\mathrm{\Lambda }}^3$H and ${}_{\mathrm{\Lambda }}^4$H are compared with those of the copiously produced particles such as p, $\mathrm{\Lambda }$, d, t,${}^3$He and ${}^4$He. It is observed that the slopes of $v_1$ at midrapidity for the hyper-nuclei ${}_{\mathrm{\Lambda }}^3$H and ${}_{\mathrm{\Lambda }}^4$H follow a baryon number scaling implying that coalescence process is a dominant mechanism for the hyper-nuclei production in these collisions. Hypernuclei directed flow measurement would shed light on the hyperon-nucleon (YN) interaction in condensed nuclear medium with finite pressure.

Presentation materials

ATHIC2021_Hypernuclei-flow-YapengZhang.pdf