Fragment production in 16O+80Br reaction within dynamical microscopic theory

Abstract

We analyze the formation of fragments in O·Br reaction at different incident energies between E A 50 MeV and 200 MeV. This study is carried out within the quantum molecular dynamics (QMD) model coupled with recently advanced simulated annealing clusterization algorithm (SACA). For comparison, we also use the conventional minimum spanning tree (MST) method. Our detailed study shows that the SACA can detect the final stable fragment configuration as early as 60 fm/c which is marked by a dip in the heaviest fragment. On the other hand, the MST method needs several hundred fm/c to identify the final stable distribution. A comparison of the charge distribution with experimental data shows that the SACA is able to reproduce the data very nicely whereas (as reported earlier) the MST method fails to break the spectator matter into intermediate mass fragments. Furthermore, our results with SACA method indicate the onset of multi-fragmentation around 75 MeV/A which is again in good agreement with experimental findings.

On the stability of fragments and thermalization achieved in neutron-rich heavy-ion collisions

“…One of the important aspects in fragmentation is the stability of the fragments as well as the nucleons surrounding a fragment. The change in the nucleon content of the fragments between two successive time steps can be quantified with the help of the persistence coefficient [24,25].…”

“…But it does not provide any information on whether a fragment has swallowed several nucleons or not. To check this, we use a quantity called the "Gain" [25]. The Gain represents the percentage of nucleons that a fragment has swallowed between two consecutive time steps.…”

Stability of the fragments and thermalization at the peak centre-of-mass energy

“…But it does not provide any information whether a fragment has swallowed some nucleons or not. To check this, we use a quantity called "Gain" [18]. The…”

“…One of the important aspects in fragmentation is the stability of fragments as well as surrounding nucleons of a fragment. The change in the nucleon content of fragments between two successive time steps can be quantified with the help of persistence coefficient [17,18].…”

“…This study is made within the framework of the quantum molecular dynamics model, which is described in detail in Refs. [1,4,[11][12][13][14][15][16][17][18].…”