Collisions of {sup 28}Si+Al, Cu, and Pb at {ital E}{sub lab}=14.6 GeV/nucleon were studied at the Brookhaven National Laboratory Alternating Gradient Synchrotron. Charged particle multiplicity was ...measured over the pseudorapidity interval 0.875{le}{eta}{le}3.86 with a silicon pad detector. A strong correlation is seen between the multiplicity and the transverse energy measured in the interval {minus}0.5{le}{eta}{le}0.8. Correlation with the energy going forward after the collision and comparison with calculations indicate that rescattering is required to explain the data. The data are compared under the assumption of Koba-Nielson-Olesen scaling. The measured multiplicity scales approximately with the total number of participant nucleons and less well with the available center-of-mass kinetic energy.
We report a direct measurement of the final-state energy spectrum in the electromagnetic dissociation of {sup 28}Si into {ital p}+ {sup 27}Al at an energy of 14.6 GeV/nucleon. The final-state energy ...is obtained through a calculation of the {ital p}-{sup 27}Al invariant mass in kinematically reconstructed events. The final-state energy spectrum for all targets is peaked near the isovector giant-dipole resonance in {sup 28}Si and the dependence of the magnitude of the cross section on target charge confirms that the excitation is largely electromagnetic. By exploiting the expected scaling behavior on target {ital Z} and {ital A}, the background from nuclear interactions is evaluated and subtracted, leaving a pure electromagnetic dissociation final-state energy distribution. This distribution is well reproduced by simulated events, in which the photon spectrum calculated in the Weiszaecker-Williams approximation is combined with experimental data on the photonuclear reaction {sup 28}Si({gamma},{ital p}) {sup 27}Al, and slight differences are observed only at low final-state energy.
Phys.Lett. B485 (2000) 319-326 Directed flow of antiprotons is studied in Au+Au collisions at a beam
momentum of 11.5A GeV/c. It is shown that antiproton directed flow is
anti-correlated to proton ...flow. The measured transverse momentum dependence of
the antiproton flow is compared with predictions of the RQMD event generator.
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