Momentum flow in the 800 MeV/nucleon Ar + Pb reaction

The global variables R-ratio, flux-angle and aspect-ratio were used along with the newly-introduced technique of azimuthal rotation to analyze semi-exclusive data of central collisions of 800 MeV/nucleon Ar + Pb. For high multiplicities, which were shown to correspond to small impact parameters, the data approach a thermal isotropic distribution. For larger impact parameters (lower multiplicity subsamples) a finite deflection of the flux tensor is observed after azimuthal rotation of the flux tensor. This deflection is also observed in the contour plots of p/sub perpendicular/ as a function of rapidity of the azimuthally rotated data sample. The event shapes for the larger impact parameters are prolate. There is no indication from these data for oblate event shapes which would be created in very central collisions by enhanced particle emission at 90 degrees in the cm as predicted by the one fluid hydrodynamical model. Furthermore, there is a significant difference between the data and the intranuclear cascade model in that the cascade events are consistently oriented closer to the beam direction than the data, particularly at larger impact parameters