Directed flow in an extended multiphase transport model

TL;DR

This study investigates the directed flow in gold-gold collisions across various energies using an extended transport model, revealing sensitivities to partonic interactions and hadronization, and challenging the necessity of a first-order phase transition for negative proton flow.

Contribution

It introduces an extended multiphase transport model that incorporates both partonic and hadronic mean-field potentials to analyze directed flow in heavy-ion collisions.

Findings

Directed flow is mainly influenced by partonic scatterings and hadronization.

Negative proton flow slope does not require a first-order phase transition.

The model reproduces experimental directed flow data across energies.

Abstract

We have studied the rapidity-odd directed flow in $^{197}$Au+$^{197}$Au collisions in the beam energy range from $\sqrt{s_{NN}}$ = 7.7 to 39 GeV within the framework of an extended multiphase transport model with both partonic and hadronic mean-field potentials incorporated. Effects of the partonic scatterings, mean-field potentials, hadronization, and hadronic evolution on the directed flow are investigated, and it is found that the final directed flow is mostly sensitive to the partonic scatterings and the hadronization mechanism. Our study shows that a negative slope of the proton directed flow does not necessarily need the equation of state with a first-order phase transition.