Onset of pressure gradient on collective flow through balance and transition geometry

Abstract

The impression of mean field and spectator matter has been studied through the collision geometry dependence of reduced flow and elliptical flow in heavy-ion collisions (HICs) at intermediate energies using Isospindependent Quantum Molecular Dynamics (IQMD) model for the reaction of $$_{20}^{50}{\rm{Cu + }}_{20}^{50}{\rm{and}}_{79}^{197}{\rm{Au + }}_{79}^{197}{\rm{Au}}$$ at incident energy between 50 MeV/nucleon and 450 MeV/nucleon. The collision geometry at which the reduced flow and elliptical flow changes its sign is termed as balance geometry $$({\hat b_{bal}})$$ and transition geometry $$({\hat b_{trans}})$$ of flow, respectively. Our study reveals that $$({\hat b_{bal}})$$ and $$({\hat b_{trans}})$$ increases with increase in incident energy. In addition to this, the effect of nuclear charge radius has also been studied by using the isospin-independent as well dependent nuclear charge radii parameterizations.