Flow and Equation of State of nuclear matter at $\mathbf{E_{\mathrm{kin}}}$/A=0.25-1.5 GeV with the SMASH transport approach

TL;DR

This paper compares experimental flow data from heavy-ion collisions with simulations using the SMASH transport model, exploring how different nuclear equations of state affect the observed collective flow at energies between 0.25 and 1.5 GeV per nucleon.

Contribution

It introduces momentum-dependent potentials into the SMASH model and systematically analyzes their impact on flow observables across a range of energies.

Findings

Soft momentum-dependent potential best fits low-energy flow data.

Harder momentum-dependent potential better describes high-energy elliptic flow.

The study constrains the nuclear Equation of State based on flow measurements.

Abstract

We present a comparison of directed and elliptic flow data by the FOPI collaboration in Au--Au, Xe--CsI, and Ni--Ni collisions at beam kinetic energies from 0.25 to 1.5 GeV per nucleon to simulations using the SMASH hadronic transport model. The Equation of State is parameterized as a function of nuclear density and momentum dependent potentials are newly introduced in SMASH. With a statistical analysis, we show that within the present status of the SMASH transport model, the collective flow data at lower energies is in the best agreement with a soft momentum dependent potential, while the elliptic flow at higher energies requires a harder momentum dependent Equation of State.