We present new experimental results concerning the azimuthal distributions of proton-likes, light and intermediate mass fragments at midrapidity for Au( 100-800 A MeV)+ Au collisions measured with the FOPI phase-I detector at GSI in Darmstadt. The azimuthal distributions are investigated as a function of the collision centrality, the incident energy, the fragment charge and transverse momentum. The azimuthal anisotropy is maximum for impact parameters around 7 fm. Intermediate mass fragments present a stronger out-of-plane emission signal than light fragments and a saturation is reached for Z ≥ 4. The azimuthal anisotropy increases with the fragment transverse momentum and decreases as the incident energy increases. The azimuthal anisotropy of Z = 2 particles investigated as a function of the scaled fragment transverse momentum follows an universal curve for bombarding energies between 250-800 A MeV. A signature for a transition from in-plane to out-of-plane emission is evidenced at the lowest beam energies.
- Measured fragment azimuthal anisotropy vs collision centrality, fragment charge, transverse momentum, incident energy
- Nuclear reactions Au (Au,X), E = 100-800 MeV/nucleon
ASJC Scopus subject areas
- Nuclear and High Energy Physics