Evolutions of in-medium baryon-baryon scattering cross sections and stiffness of dense nuclear matter from Bayesian analyses of FOPI proton flow excitation functions

Abstract

Within a Bayesian statistical framework using a Gaussian Process (GP) emulator for an isospin-dependent Boltzmann-Uehling-Uhlenbeck (IBUU) transport model simulator of heavy-ion reactions with momentum-independent Skyrme interactions, we infer from the proton directed and elliptical flow in mid-central Au+Au reactions at beam energies from 150 to 1200 MeV/nucleon taken by the FOPI Collaboration the posterior Probability Distribution Functions (PDFs) of the in-medium baryon-baryon scattering cross section (BBSCS) modification factor $X$ (with respect to their free-space values) and the stiffness parameter $K$ of dense nuclear matter. We find that the most probable value of $X$ evolves from around 0.7 to 1.0 as the beam energy $E_{beam}/A$ increases. On the other hand, the posterior PDF($K$) may have dual peaks having roughly the same height or extended shoulders at high $K$ values. More quantitatively, the posterior PDF($K$) changes from having a major peak around 220 MeV characterizing a soft EOS in the reaction at $E_{beam}/A$=150 MeV to one that peaks around 320 MeV indicating a stiff EOS in the reactions at $E_{beam}/A$ higher than about 600 MeV. The transition from soft to stiff happens in mid-central Au+Au reactions at beam energies around 250 MeV/nucleon in which $K=220$ MeV and $K=320$ MeV are approximately equally probable. Altogether, the FOPI proton flow excitation function data indicate a gradual hardening of hot and dense nuclear matter as its density and temperature increase in reactions with higher beam energies.

Added more discussions. Phys. Rev. C in press

References in corpus (21)

• Transverse momentum analysis of collective motion in relativistic nuclear collisions
• Progress in Constraining Nuclear Symmetry Energy Using Neutron Star Observables Since GW170817
• Dense Nuclear Matter Equation of State from Heavy-Ion Collisions
• Constraining the Eq. of State of Super-Hadronic Matter from Heavy-Ion Collisions
• Quantifying properties of hot and dense QCD matter through systematic model-to-data comparison
• In-medium NN cross sections determined from stopping and collective flow in intermediate-energy heavy-ion collisions
• The Present and Future of QCD
• In-medium effects for nuclear matter in the Fermi energy domain
• The QCD phase diagram and Beam Energy Scan physics: a theory overview
• Accessing the in-medium effects on nucleon-nucleon elastic cross section with collective flows and nuclear stopping
• Nuclear incompressibility and sound speed in uniform matter and finite nuclei
• Bayesian Inference of Fine-Features of Nuclear Equation of State from Future Neutron Star Radius Measurements to 0.1km Accuracy
• Studies of the equation-of-state of nuclear matter by heavy-ion collisions at intermediate energy in the multi-messenger era
• Correlation between elliptic flow and shear viscosity in intermediate-energy heavy-ion collisions
• Bayesian inference of in-medium baryon-baryon scattering cross sections from HADES proton flow data
• Flow and Equation of State of nuclear matter at ${\mathbf{E}}_{\mathrm{kin}}$/A=0.25-1.5 GeV with the SMASH transport approach
• Elliptic flow in heavy-ion collisions at intermediate energy: the role of impact parameter, mean field potential, and collision term
• Constraining nucleon effective masses with flow and stopping observables from the S$\pi$RIT experiment
• Effects of incompressibility $K_0$ in heavy-ion collisions at intermediate energies
• Neural Network Emulation of Flow in Heavy-Ion Collisions at Intermediate Energies
• Principal Component Analysis of Azimuthal Flow in Intermediate-Energy Heavy-Ion Reactions

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