Size and excitation energy distributions of projectile spectators in multifragmentation data

The size and energy distributions of spectators in ALADIN fragmentation experiments with gold projectiles are inferred from experimental data. For the most violent collisions of Au on Cu, the mean projectile spectator has the size of an iron nucleus, with an excitation energy of about 23 MeV/nucleon. We claim that a correct interpretation of these data should take into account the large range covered by the extracted distributions, which are in good agreement with the prediction of the Boltzmann-Uheling-Uhlenbeck calculations and with those of a new diabatic abrasion model.