Evidence for fast and simultaneous multi-fragment emission in central Kr + Au collisions at 60 MeV/u

Abstract Decay products emitted in Kr+Au collisions at 60 MeV/u have been detected with a large experimental array. Events with fragment multiplicities up to 5 have been recorded. After a careful selection of central collisions leading to equilibrited events, the data are compared to two fragmentation models in which fragments are emitted either sequentially or simultaneously. It is shown that the data can be explained very well by the second model, thus suggesting a prompt multifragmentation mechanism. Possible expansion effects in the disassembly process are also investigated.