Speaker
Description
Strangeness production has been suggested as a sensitive probe to the early dynamics of the deconfined matter created in heavy-ion collisions.
There are significant discussions in the field about the initial conditions, including the colliding energy and the size of the system, needed to generate a quark-gluon plasma (QGP). It is expected that the threshold can be revealed by the measurements of the colliding energy and system size dependence of baryon-to-meson enhancement. Recent datasets collected by STAR in Au+Au collisions at $\sqrt{s_{NN}}$ = 7.7, 9.2, 11.5, 14.6, 17.3 and 19.6 GeV from the Beam Energy Scan II program and in different collision systems at $\sqrt{s_{NN}}$ = 200 GeV (d+Au, Au+Au, O+O, Zr+Zr, Ru+Ru) provide us a chance to look into the $\Omega$/$\phi$ ratios and possibly locate the threshold of QGP production.
In addition, (multi)strange hadron to pion yield versus multiplicity in different collision systems at $\sqrt{s_{NN}}$ = 200 GeV can be compared with the results from LHC, where an intriguingly smooth increase in these ratios was first reported.
Furthermore, rapidity density of (anti-)strange baryons may give insight into the baryon stopping mechanism.
In this talk, we will present new measurements of strange hadron ($K_s^0$, $\Lambda$, $\bar{\Lambda}$, $\Xi$, $\bar{\Xi}$, $\Omega$, $\bar{\Omega}$, $\phi$) production in Au+Au collisions at $\sqrt{s_{NN}}$ = 7.7, 9.2, 11.5, 14.6, 17.3, 19.6, 200 GeV and in d+Au, O+O, Zr+Zr and Ru+Ru collisions at $\sqrt{s_{NN}}$ = 200 GeV, including transverse-momentum and rapidity spectra, nuclear modification factors, antibaryon-to-baryon ratios and baryon-to-meson ratios. In particular, precise measurements of the energy and centrality dependence of $\Omega$/$\phi$ ratios in Au+Au collisions at different energies and in different collision systems at $\sqrt{s_{NN}}$ = 200 GeV will be presented. In addition, (multi)strange hadron to pion yield versus multiplicity in different collision systems at $\sqrt{s_{NN}}$ = 200 GeV will also be reported.
These results will be compared to theoretical calculations and physics implications will be discussed.
| Category | Experiment |
|---|---|
| Collaboration (if applicable) | STAR |
