Collisions of Au on Au at incident energies of 150, 250 and 400 A MeV were studied with the FOPI-facility at GSI Darmstadt. Nuclear charge (Z ≤ 15) and velocity of the products were detected with full azimuthal acceptance at laboratory angles 1 • ≤ θ lab ≤ 30 • . Isotope separated light charged particles were measured with movable multiple telescopes in an angular range of 6 − 90 • . Central collisions representing about 1% of the reaction cross section were selected by requiring high total transverse energy, but vanishing sideflow. The velocity space distributions and yields of the emitted fragments are reported. The data are analysed in terms of a thermal model including radial flow. A comparison with predictions of the Quantum Molecular Model is presented.PACS: 25.70.Pq

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The incident energy at which the azimuthal distributions in semi-central heavy ion collisions change from in-plane to out-of-plane enhancement -E tran is studied as a function of mass of emitted particles, their transverse momentum and centrality for Au+Au collisions. The analysis is performed in a reference frame rotated with the sidewards flow angle (Θ f low ) relative to the beam axis.A systematic decrease of E tran as function of mass of the reaction products, their transverse momentum and collision centrality is evidenced.The predictions of a microscopic transport model (IQMD) are compared with the experimental results.

The photon decay of the relativistic Coulomb excitation of the single and double giant dipole resonance (GDR) in the target has been observed in the system 1A GeV 209 Bi on 208 Pb. For peripheral events which are dominated by relativistic Coulomb excitation, a large Lorentzian structure in the photon energy spectrum is peaked at 13.3±0.

The mass distributions of baryon resonances populated in near-central collisions of Au on Au and Ni on Ni are deduced by defolding the $p_t$ spectra of charged pions by a method which does not depend on a specific resonance shape. In addition the mass distributions of resonances are obtained from the invariant masses of $(p, \pi^{\pm})$ pairs. With both methods the deduced mass distributions are shifted by an average value of -60 MeV/c$^2$ relative to the mass distribution of the free $\Delta(1232)$ resonance, the distributions descent almost exponentially towards mass values of 2000 MeV/c^2. The observed differences between $(p, \pi^-)$ and $(p, \pi^+)$ pairs indicate a contribution of isospin $I = 1/2$ resonances. The attempt to consistently describe the deduced mass distributions and the reconstructed kinetic energy spectra of the resonances leads to new insights about the freeze out conditions, i.e. to rather low temperatures and large expansion velocities