Momentum dependent potentials from a parity doubling CMF model in UrQMD: Results on flow and particle production

TL;DR

This paper extends the UrQMD model with momentum dependent potentials from a parity doubling CMF model, improving the description of particle production and flow in heavy ion collisions across various energies.

Contribution

It introduces a new implementation of momentum dependent potentials from a parity doubling CMF model into UrQMD, enhancing its accuracy in simulating heavy ion collision observables.

Findings

Improved agreement with experimental data on particle production and flow.

Enhanced description of hyperon and pion yields at SIS18 energies.

Indication that current parametrization has slightly weak momentum dependence.

Abstract

The quantum molecular dynamics (QMD) part of the UrQMD model is extended to allow implementation of momentum dependent potentials from a parity doubling chiral mean field (CMF) model. Important aspects like energy conservation and effects on particle production and flow are discussed. It is shown, that this new implementation reproduces qualitatively and quantitatively available data over a wide range of beam energies and improves the description of observables without exception. In particular the description of hyperon and pion production at SIS18 energies is improved. From a comparison with HADES data one could conclude that the present parametrization of the CMF model leads to a slightly too weak momentum dependence. However, a more firm conclusion will require a systematic comparison with flow and multiplicity data over a range of beam energies and system sizes. Our work serves as an important step towards such future studies where the properties of dense QCD matter, through parameters of the CMF model, can be constraint using a comparison of the UrQMD model with high precision heavy ion data, finally also allowing direct comparisons with neutron star and neutron star merger observables.