Probing of EoS with clusters and hypernuclei

Abstract

The study of the nuclear equation-of-state (EoS) is a one of the primary goals of experimental and theoretical heavy-ion physics. The comparison of recent high statistics data from the STAR Collaboration with transport models provides a unique possibility to address this topic in a yet unexplored energy domain. Employing the microscopic N-body Parton-Hadron-Quantum-Molecular Dynamics (PHQMD) transport approach, which allows to describe the propagation and interactions of hadronic and partonic degrees of freedom including cluster and hyper-nucleus formation and dynamics, we investigate the influence of different EoS on bulk observables, the multiplicity, $p_T$ and rapidity distributions of protons, $Λ$s and clusters up to A=4 as well as their influence on the collective flow. We explore three different EoS: two static EoS, dubbed 'soft' and 'hard', which differ in the compressibility modulus, as well as a soft momentum dependent EoS. We find that a soft momentum dependent EoS reproduces most baryon and cluster observables, including the flow observables, quantitatively, however, hard EOS show a similar trend.

Figures (26)

• Figure 1: Top: Schrödinger equivalent optical potential $U_{opt}$ versus the absolute value of relative momentum $p$ of the proton extracted from pA collisions Hama:1990vrClark:2006rjCooper:1993nx. Bottom; The distribution of the relative momenta among the nucleons for different times and for Au+Au collisions at $\sqrt{s_{\rm NN}}=3\rm GeV$.
• Figure 2: Equation-of-state for $T=0$ for the hard (green line), soft (blue line) and the soft momentum-dependent potential (red line).
• Figure 3: Rapidity distribution (integrated over all $p_T$) of protons (upper row), deuterons (middle row), and tritons (lower row) from PHQMD simulations of Au+Au collisions at $\sqrt{s_{\rm{NN}}}=3$ GeV (left column) and 5.4 GeV (right column) in the 0–10% centrality class. Results are shown for the three different parameterizations of the nuclear optical potential (Parameterization I, II, and III) of Fig. \ref{['fig:uopt']}.
• Figure 4: The in-plane flow $v_1(p_T)$ near target rapidity ($-1<y<-0.5$) of protons and deuterons from PHQMD simulations of Au+Au collisions at $\sqrt{s_{\rm{NN}}}=3$ GeV (left column) and 5.4 GeV (right column) in the 10–40% centrality class. Results are shown for three different parameterizations of the nuclear optical potential (Parameterization I, II, and III).
• Figure 5: The elliptic flow $v_2(p_T)$ at mid-rapidity ($-0.5<y<0$) of protons and deuterons from PHQMD simulations of Au+Au collisions at $\sqrt{s_{\rm{NN}}}=3$ GeV (left column) and 5.4 GeV (right column) in the 10–40% centrality class. Results are shown for three different parameterizations of the nuclear optical potential (Parameterization I, II, and III).