OUT-OF-PLANE EMISSION OF NUCLEAR-MATTER IN AU+AU COLLISIONS BETWEEN 100 AND 800 A MEV

We present new experimental results concerning the azimuthal distribut ions of proton-likes, light and intermediate mass fragments at midrapi dity for Au(100-800 AMeV)+Au collisions measured with the FOPI phase-I detector at GSI in Darmstadt. The azimuthal distributions are investi gated 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 fragme nts present a stronger out-of-plane emission signal than light fragmen ts and a saturation is reached for Z greater than or equal to 4. The a zimuthal anisotropy increases with the fragment transverse momentum an d 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 AMeV. A signature for a transition from in-plane to o ut-of-plane emission is evidenced at the lowest beam energies. (C) 199 7 Elsevier Science B.V.