Using the FOPI detector at GSI Darmstadt, excitation functions of collective flow components were measured for the Au+Au system, in the reaction plane and out of this plane, at seven incident energies ranging from 100AMeV to 800AMeV. The threshold energies, corresponding to the onset of sideward-flow (balance energy) and squeeze-out effect (transition energy), are extracted from extrapolations of these excitation functions toward lower beam energies for charged products with Z ≥ 2. The transition energy is found to be larger than the balance energy. The impact parameter dependence of both balance and transition energies, when extrapolated to central collisions, suggests comparable although slightly higher values than the threshold energy for the radial flow. The relevant parameter seems to be the energy deposited into the system in order to overcome the attractive nuclear forces.
Bibliographical noteFunding Information:
This work was supporteidn part by the French-Germaang reemenbte tweenG SI and IN2P3/CEA and by the PROCOPE-Programo f the DAAD.
- Balance energy
- Heavy ion collisions
- Nuclear matter expansion
- Radial flow
- Transition energy
ASJC Scopus subject areas
- Nuclear and High Energy Physics