Speaker
Description
Directed flow of particles is an important feature seen in heavy-ion collisions and is a sensitive probe to the equation of state (EoS) of the matter produced in the collisions. Model calculations have also predicted that directed flow could be sensitive to the softening of EoS associated with a first order phase transition. Directed flow of protons and anti-protons are also of interest as they offer sensitivity to both the contributions from the transported quarks and the component generated by medium interactions at the later stage. Measurements of proton and net proton directed flow from BES-I have shown that there is a non-monotonous dependence on collision energy.
In this poster, We will present measurements of the directed flow of protons and antiprotons from 19.6, 14.5, 11.5, 9.2, and 7.7 GeV Au+Au collisions, using high statistics BES-II data from STAR. We will also present a decomposition of proton directed flow into a medium interaction generated component and a component (v1excess) attributed to transported protons. The v1excess component is found to show a simple scaling between collision energies of 200 GeV to ~10 GeV, but to break the scaling at energies below that. The new results have significantly reduced uncertainties and also allow differential measurements in centrality and transverse momentum. Results will be compared to different model calculations and implications to the understanding of the QCD phase structure and EoS of the medium will be discussed.
| Category | Experiment |
|---|---|
| Collaboration (if applicable) | STAR |
