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Transport simulations with a constrained momentum-dependent chiral mean-field equation of state at various isospin fractions

Jan Steinheimer1,2,* and Marcus Bleicher3,4

  • *Contact author: j.steinheimer-froschauer@gsi.de
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Phys. Rev. C 114, 044904 – Published 13 October, 2026

DOI: https://doi.org/10.1103/6j14-cm4m

Abstract

We present a comparison of the ultrarelativistic quantum molecular dynamics model using a chiral mean field (CMF) equation of state with flow and pion production data in heavy ion collisions at low beam energies Elab=0.2–2.0A GeV and varying isospin fraction. The CMF model parameters are constrained by known properties of the high density equation of state of quantum chromodynamics at varying isospin fractions. This allows us to calculate the equation of state as well as nuclear interactions for different physical systems like neutron stars and heavy ion collisions in a consistent way. It is found that heavy ion reactions at the upcoming FAIR facility will only have marginal sensitivity on the isospin dependence of the high-density equation of state. At lower beam energies, comparing to FOPI, HADES, and SπRIT data, the sensitivity is higher but the observed deviations and systematic uncertainties of the existing data are larger than the sensitivity to the symmetry energy.

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Phys. Rev. C 114, 044904– Published 13 October, 2026
  • Received 19 June 2026
  • Accepted 11 September 2026
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