Bayesian analysis of properties of nuclear matter with the FOPI experimental data

Abstract

Based on the ultra-relativistic quantum molecular dynamics (UrQMD) transport model, combined with experimental data of directed flow, elliptic flow, and nuclear stopping power measured by FOPI in ${}^{197}\mathrm{Au}{+}^{197}\mathrm{Au}$ collisions at beam energies ($E_{lab}$) of 0.25 and 0.4 GeV/nucleon, the incompressibility of the nuclear equation of state $K_0$, the nucleon effective mass $m^{\ast }$, and the in-medium correction factor ($F$, with respect to free-space values) on the nucleon-nucleon elastic cross sections are studied by Bayesian analysis. It is found that both $m^{\ast }$ and $F$ can be tightly constrained with the uncertainty $\le$ 15\%, however, $K_0$ cannot be constrained tightly. We deduce $m^{\ast }/m_0=0.78_{-0.10}^{+0.09}$ and $F=0.75_{-0.07}^{+0.08}$ with experimental data at $E_{lab}$ = 0.25 GeV/nucleon, and the obtained values increased to $m^{\ast }/m_0=0.88_{-0.03}^{+0.03}$ and $F=0.88_{-0.07}^{+0.06}$ at $E_{lab}$ = 0.4 GeV/nucleon. The obtained results are further verified with rapidity-dependent flow data.

Comments: 10 pages, 7 figures