Multifragmentation of very heavy nuclear systems (III): Fragment velocity correlations and event topology at freeze-out

Abstract

Kinetic energy spectra and fragment velocity correlations, simulated by means of stochastic mean-field calculations, are successfully confronted with experimental data for single multifragmenting sources prepared at the same excitation energy per nucleon in 32 AMeV 129 Xe+ nat Sn and 36 AMeV 155 Gd+ nat U central collisions. Relying thus on simulations, average freeze-out times of 200-240 fm/c are estimated The corresponding spatial distributions of fragments are more compact for the lighter system (∼3-4V 0 vs ∼8V 0 ).

Nuclear multifragmentation and phase transition for hot nuclei

“…frame of fragments emitted by compact multifragmenting sources were shown in [78] for the two heavy systems 32 MeV/nucleon Xe+Sn and 36 MeV/nucleon Gd+U. They have asymmetric shapes for the lighter fragments, and tend to become more symmetric for Z≥15.…”

Systematics of stopping and flow in Au+ Au collisions

“…5) and the degree of pionization. An idea of the freeze-out volume can be obtained from two-particle correlations [151], or even multi-particle correlations [152,153]. All this is a rather challenging task.…”

Coulomb chronometry to probe the decay mechanism of hot nuclei

“…In the case of central collisions, two-fragment correlation functions have been used to extract emission time scales in multifragmentation events, typically observed at intermediate energies [22][23][24][25][26][27]. The extracted emission properties are affected by space-time ambiguities.…”