Flow vorticity in peripheral high-energy heavy-ion collisions

Abstract

Vorticity development is studied in the reaction plane of peripheral relativistic heavy-ion reactions where the initial state has substantial angular momentum. The earlier predicted rotation effect and Kelvin Helmholtz instability lead to significant initial vorticity and circulation. In low-viscosity quark gluon plasma this vorticity remains still significant at the time of freeze-out of the system, even if damping due to explosive expansion and dissipation decreases the vorticity and circulation. In the reaction plane the vorticity arises from the initial angular momentum, and it is stronger than in the transverse plane, where vorticity is caused by random fluctuations only.