Nuclear Fluid Dynamics versus Intranuclear Cascade—Possible Evidence for Collective Flow in Central High-Energy Nuclear Collisions

The predictions of a variety of current theoretical models of high-energy nuclear collisions are compared with recent experimental data for central collisions of $^{20}\mathrm{Ne}$ on $^{238}\mathrm{U}$ at ${E}_{\mathrm{lab}}=393$ MeV/u. The experimental observation of broad sideward maxima in the angular distributions of low- and medium-energy protons is reproduced by a nuclear fluid-dynamical calculation with final freezeout of the protons. In contrast, the current intranuclear-cascade and simplified collision models predict forward-peaked angular distributions.