Flow and vorticity with varying chemical potential in relativistic heavy ion collisions

Abhisek Saha, Soma Sanyal

Published 2019-02-22Version 1

We study the vorticity patterns in relativistic heavy ion collisions with respect to the collision energy. The collision energy is related to the chemical potential used in the thermal - statistical models that assume approximate chemical equilibrium after the relativistic collision. We use the multiphase transport model (AMPT) to study the vorticity in the initial parton phase as well as the final hadronic phase of the relativistic heavy ion collision. Both the bulk viscosity and the shear viscosity are involved in the generation of the net vorticity in the plasma. These can also be expressed in terms of the baryon density and the chemical potential in hadron resonance gas models. We find that as the chemical potential increases, the vortices become weaker and larger in size. We also look at the elliptic flow as it is related to viscous effects in the final stages after the collision. Our results indicate that the bulk viscosity plays a greater role at higher chemical potential and lower collision energies. They also indicate that viscous hydrodynamic results from the hadron resonance gas model and the hybrid transport models compliment each other.