Elliptic Flow in Heavy Ion Nuclear Reactions

Abstract

Elliptic flow develops because of almond shape of the overlapping region in a heavy ion collision. Elliptical or higher order azimuthal shapes can provide help (a) when the phase space coverage is limited to a narrow region around midrapidity, and (b) at beam energies close to the balance energy, where no net deflection of nucleons is observed. The elliptic flow is expected to be larger in more peripheral collisions because of the anisotropy in coordinate space which is the source of this flow. The study of elliptic flow provides valuable data on the nuclear equation of state and isospin dependent N-N cross section. Study of dependence of elliptic flow and different fragment flows on beam energies, mass number, isospin and impact parameter have revealed quite interesting physics about the properties and origin of collective flow.