High-energy proton emission and Fermi motion in intermediate-energy heavy-ion collisions

An antisymmetrized molecular dynamics model (AMD-FM), modified to take into account the Fermi motion explicitly in its nucleon-nucleon collision process, is presented. Calculated high-energy proton spectra are compared with those of Ar-40 + V-51 at 44 MeV/nucleon from Coniglione et al. [Phys. Lett. B 471, 339 (2000)] and those of Ar-36 + Ta-181 at 94 MeV/nucleon from Germain et al. [Nucl. Phys. A 620, 81 (1997)]. Both of the experimental data are reasonably well reproduced by the newly added Fermi boost in the nucleon-nucleon collision process without additional processes, such as a three-body collision or a short-range correlation. The production mechanism of high-energy protons in intermediate-energy heavy-ion collisions is discussed.