[en] By studying protons from the multifragmentation of 1AGeV Au + C collisions, we can distinguish two stages in the reaction process. A method for separating these two components will be presented

[en] The EOS Collaboration, consisting of groups from GSI, Kent State University, Lawrence Berkeley Laboratory, INFN Catania, Purdue University, Texas A ampersand M, and U.C. Davis, has been interested in flow and multifragmentation for over ten years. The Purdue High Energy Nuclear Physics Group studies of proton-nucleus collisions using an internal gas jet target of heavy noble gases allowed them to accurately measure target fragment yields over a wide range of fragment mass, charge, and incident energies. A high statistics study of the fragment yield in the limiting fragmentation regime provided evidence that heavy fragments come from the simultaneous disassembly of a system somewhat lighter than the original target nucleus and nearly at rest in the laboratory. Complementary studies indicated that the missing nucleons were knocked out in a prompt first stage, leaving the excited target remnant to decay. With the development of time projection chambers (TPCs) it has become possible to reconstruct all of the charged fragments. The author reports here some preliminary results from the EOS Collaboration experiment in which they used reverse kinematics to study projectile fragmentation of 1 GeV/nucleon gold nuclei incident on a carbon target

[en] The characteristics of intermediate mass fragment kinetic energy spectra produced in 1 AGeV Au+C collisions are investigated as a means of determining the conditions at freezeout in multiframentation

[en] Data for the fragmentation of high energy gold projectiles were recently analyzed by Dreute et al. with the assumption that the average A/Z ratio of the residues was equal to that of the projectile. The momenta of the projectile fragments from this analysis were dramatically larger than expected. We point out that the assumption of a constant A/Z is inconsistent with a large body of data and leads to an overestimation of both the fragment mass and the momentum distribution. A better description of the variation of the residue A/Z ratio can be found in the prescription developed by Suemmerer et al. based on a broad range of data

[en] We have used the bond percolation model to study the multifragmentation of ¹⁹⁷Au projectiles after collisions with a Cu target at an incident energy of 600 MeV/nucleon. The charge correlations have been analysed. The theoretical results agree well with the experimental data of the ALADIN collaboration. This shows that the percolation model can reasonably describe the universal property of nuclear fragmentation in nucleus-nucleus collisions. (author)

[en] We present preliminary results for the emission of target rapidity protons in minimum bias and central 11.7 A.GeV/c Au+Au collisions. The data span the pseudo-rapidity range |η| ≤ 0.76 and proton kinetic energy range of 50 ≤ E ≤ 200 MeV. The slopes of the kinetic energy spectra and dN/dη values for central and minimum bias collisions are strikingly similar. Comparison of the results to results for Si+Au and p+A shows that the shape of the dN/dη distribution is independent of the reaction system or centrality suggesting that the spectator matter does not play a decisive role in determining the shape of the proton distributions at back angles for these systems at AGS energies

[en] Measurements are presented of single particle spectra using the recently commissioned Au beam at 11.6 A.GeV/c (E-866) and the Si beam at 14.6 A.GeV/c (E-802) from the BNL Tandem-Booster-AGS accelerators facilities. The E-802 magnetic spectrometer was used to make the measurements. Data for both minimum bias and central collisions were collected. An forward calorimeter (ZCAL) and a target multiplicity array (TMA) provided a centrality triggers. For protons, the multiplicity density dN/dy suggests that a fairly large amount of open-quotes stoppingclose quotes has been achieved in central collisions for the heavy systems. The inverse slope parameters T show a broader distribution versus rapidity in Au+Au than in lighter systems. From the deuteron and proton data and by using a thermal coalescence model, it has been found that the size of the interaction region is larger than the size of the projectile. Some comparisons of the new Au+Au data with the final E-802 data (Si+A) and the relativistic cascade code ARC will be made

[en] We study Au +Au reactions at several energies ranging from 250 MeV/A up to 2 GeV/A with BUU theory and with a coalescence model to approximate the final state of protons and light composites. Energy spectra are analyzed in terms of a radially expanding thermal source and global fits determine flow velocities and temperatures. Sensitivity to equations of state, in-medium cross sections, Coulomb and compression effects are all investigated. The results are quite consistent with data from the EOS-TPC collaboration but seem to suggest that the flow is less sensitive to details than would be required of a signal able to put constraints on the equation of state or other quantities

[en] The π⁺π^- balance function in rapidity is computed in a thermal model with resonances. It is found that the correlations from the neutral-resonance decays are important, yielding about a half of the total contribution, which in general consist of resonance and non-resonance parts. The model yields the pionic balance function a few per cent wider that what follows from the recent data for the Au+Au collisions at √^SNN = 130 GeV. (author)

[en] We present analyses of event-by-event dynamical net charge fluctuations measured in 130 and 200 GeV Au+Au collisions with the STAR detector. The dynamical net charge fluctuations are evaluated using the ν_+-,_dyn observable. Dynamical fluctuations measured in Au+Au collisions at 130 and 200 GeV are finite, and exceed charge conservation limits. They deviate from a perfect 1/N scaling and provide an indication that the collision dynamics varies with collision centrality. (author)