Speaker
Description
Heavy-ion collisions in the few-GeV energy range create strongly interacting matter at extreme baryon densities, comparable to those in neutron star mergers. Precise measurements of the Equation-of-State of this kind of matter in this regime are therefore essential for the understanding of neutron stars.
We present new results from HADES (High-Acceptance Dielectron Spectrometer) located at the SIS18, GSI Darmstadt, the only current setup capable of measuring rare and penetrating probes at the high-$\mu_B$ frontier of the QCD phase diagram.
High-statistics measurements of collective flow for protons and light nuclei are reported in Au+Au and Ag+Ag collisions at $\sqrt{s_{\rm NN}} = 2.42$ and $2.55\;\mathrm{GeV}$, along with recent Au+Au data at $\sqrt{s_{\rm NN}} = 1.98,\; 2.07,\; 2.16,$ and $2.24\;\mathrm{GeV}$ (beam energies $200 - 800\;A\mathrm{MeV}$), extending the excitation function to lower energies.
Beyond directed and elliptic flow, flow coefficients $v_n$ up to $6^{\text{th}}$ order are measured for the first time in this energy range, enabling a full 3D picture the angular particle emission in momentum space. Furthermore, the event-by-event flow fluctuations can be explored via correlations between the different flow coefficients, providing even stronger constraints on the Equation-of-State, and will also be presented.
The multi-differential data are compared with various transport model predictions, and current Equation-of-State constraints, e.g., from Bayesian analyses, are discussed.
Supported by the Helmholtz Forschungsakademie HFHF and GSI F$\&$E.
| Is the talk given on behalf of the Collaboration? | yes |
|---|---|
| Topic area | Phase Transition |