ENERGY-DEPENDENCE OF COLLECTIVE FLOW OF NEUTRONS AND PROTONS IN AU-197 PLUS AU-197 COLLISIONS

We investigate the beam energy dependence of neutron and proton squeez e-out in collisions of Au-197 + Au-197 at E/A = 400-800 MeV. The azimu thal anisotropy that describes the enhanced emission of mid-rapidity n eutrons perpendicular to the reaction plane rises strongly with the tr ansverse momentum of the neutrons. This dependence of the azimuthal an isotropy follows a universal curve - independent of beam energy - if t he neutron momenta are measured in fractions of the projectile momentu m per mass unit. Analogously, the kinetic energy spectra of mid-rapidi ty neutrons exhibit a universal behaviour as a function of the kinetic energy of the projectile.