Speaker
Description
Hypernuclei, bound states of nuclei with one or more hyperons, serve as a natural laboratory to investigate the hyperon-nucleon ($Y$-$N$) interaction, an important ingredient for the equation-of-state (EoS) of nuclear matter. Precise measurements of hypernuclei properties and their production yields in heavy-ion collisions are crucial for the understanding of their production mechanisms and the strength of the $Y$-$N$ interaction. The strangeness population factor, $S_{\rm A}=(^{A}_{\Lambda}\mathrm{H}/^{A}\mathrm{He})/(\Lambda/p)$ (A=3,4), is of particular interest as it directly relates to the ratio of light nuclei and hypernuclei coalescence parameters $B_{A}$. Moreover, it is suggested that $S_{A}$ might be sensitive to the onset of deconfinement. The STAR Beam Energy Scan II program and isobar collisions offer a great opportunity to investigate energy and system size dependence of hypernuclei production.
In this talk, we present new measurements on transverse momentum ($p_T$), rapidity\,($y$), and centrality dependence of $\rm ^{3}_{\Lambda}H$, $\rm ^{4}_{\Lambda}H$, and $\rm ^{4}_{\Lambda}He$ production yields in Au+Au collisions from $\sqrt{s_{\rm NN}}=$ 3 to 27 GeV, as well as in Ru+Ru and Zr+Zr collisions at $\sqrt{s_{\rm NN}}=200$ GeV. Strangeness population factors $S_{3,4}$ as functions of collision energy, centrality, $p_T$, and $y$ are also reported. In addition, we present new measurements on $\rm {}^{4}_{\Lambda}He$ and $\rm {}^{5}_{\Lambda}He$ lifetimes. These results are compared with phenomenological model calculations, and the physics implications on the hypernuclei production mechanism and properties of $Y$-$N$ interaction will be discussed.
| Category | Experiment |
|---|---|
| Collaboration (if applicable) | STAR Collaboration |
