# Revisit of directed flow in relativistic heavy-ion collisions from a multiphase transport model

## TL;DR

This study investigates the development of directed flow in relativistic heavy-ion collisions at different energies using a multiphase transport model, revealing energy-dependent flow behaviors and the effects of hadronization and rescattering.

## Contribution

It provides new insights into the energy dependence of directed flow development and the mechanisms influencing flow splitting and hadron formation in heavy-ion collisions.

## Key findings

- Partonic phase duration affects the sign of directed flow slope.
- Flow splitting varies with quark species and collision energy.
- Hadronic rescatterings modify the final directed flow of hadrons.

## Abstract

We have revisited several interesting questions on how the rapidity-odd directed flow is developed in relativistic $^{197}$Au+$^{197}$Au collisions at $\sqrt{s_{NN}}$ = 200 and 39 GeV based on a multiphase transport model. As the partonic phase evolves with time, the slope of the parton directed flow at midrapidity region changes from negative to positive as a result of the later dynamics at 200 GeV, while it remains negative at 39 GeV due to the shorter life time of the partonic phase. The directed flow splitting for various quark species due to their different initial eccentricities is observed at 39 GeV, while the splitting is very small at 200 GeV. From a dynamical coalescence algorithm with Wigner functions, we found that the directed flow of hadrons is a result of competition between the coalescence in momentum and coordinate space as well as further modifications by the hadronic rescatterings.