Beyond mean field confrontation of different models with high transverse momentum proton spectra

Several models have been proposed to simulate heavy ion reactions beyond the mean field level. The lack of data in phase space regions which may be sensitive to different treatments of fluctuations made it difficult to judge these approaches. The recently published high energy proton spectra, measured in the reaction 94 AMeV Ar + Ta, allow for the first time for a comparison of the models with data. We find that these spectra are reproduced by Quantum Molecular Dynamics (QMD) calculations. Models in which effective collective effects are introduced lead to too large proton yields. High energy proton production hence does not seem to require collective effects such as the ones needed to understand well below threshold kaon production.