Flow at AGS Energies: A Barometer for High Density Effects?

Abstract

Preliminary data on transverse energy `flow' and event asymmetries reported by the E877(814) collaborations are compared to ARC model calculations for Au+Au at full AGS beam energy. ARC triple differential cross-sections for protons and pions are presented. Proton flow is produced in ARC, with the maximum in-plane momentum about 120 MeV/c. For central events the directed momentum for pions is near zero, consistent with experiment. Pion momentum opposite to the nucleons' is evident in a peripheral sample, however, indicating that this pion `anti-flow' involves absorption by `spectator' matter. `Squeeze-out' of protons in central events at mid-rapidity is suggested by the ARC distributions.

8 pages REVTeX, 4 figures, (2 color included as GIF). Full postscript figures (LARGE) available by request from: dkahana@bnlnth.phy.bnl.gov