The AGS spectrometer experiment E-802 has measured transverse mass spectra for charged hadrons over a wide rapidity interval in Si+Au, Si+Cu, and Si+Al reactions at 14.6A G Ve/c. These results are compared for two difFerent trigger conditions: central collisions corresponding to 7% of the inelastic cross section selected on multiplicity of charged particles and peripheral collisions corresponding to roughly 50'Fo of the inelastic cross section selected on high kinetic energy at zero degrees. The invariant spectra are well described by exponentials in transverse mass allowing the extraction of rapidity distributions and inverse slope parameters for each specie emitted in the difFerent reactions.PACS number(s): 13.85.Ni, 25.75.+r

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The self-wiping co-rotating twin-screw extruder was studied as a reactor for two polymerizations in bulk: the homopolymerization of n-butylmethacrylate and the copolymerization of n-butylmethacrylate with 2-hydroxypropylmethacrylate. The influence of the extrusion parameters on the product was analyzed. With both reactions, conversions up to 95% were obtained. Nevertheless, a significant difference was observed in the working domain of both polymerizations, in which a stable reactive extrusion process could be attained wherein the discharge rate is constant and equals the feed rate. In the case of the relatively fast copolymerization, both the throughput and the screw rotation rate could be raised without endangering the stability of the process. This was not the case for the homopolymerization studied. It was determined that the stability of the process depends on the reaction velocity and the product viscosity. Within the boundaries of the working domain, the molecular weight could be influenced by adjustments of the extrusion parameters.

Two-pion correlation functions are analyzed at midrapidity for three systems (14.6A GeV/c SiϩAl, SiϩAu, and 11.6A GeV/c AuϩAu͒, seven distinct centrality conditions, and different k T bins in the range 0.1-0.5 GeV/c. Source reference frames are determined from fits to the Yano-Koonin source parametrization. Bertsch-Pratt radius parameters are shown to scale linearly with both number of projectile and total participants as obtained from a Glauber model calculation. A finite lifetime parameter that increases linearly with system/ centrality is also reported. The m T dependences of the Bertsch-Pratt radii for the central SiϩAu and central AuϩAu systems differ only by an overall normalization factor given by the measured system/centrality dependence.