New isospin e ffects in central heavy-ion collisions at Fermi energies

TL;DR

This study investigates how isospin effects influence multifragmentation in central heavy-ion collisions at Fermi energies, revealing that neutron-rich systems produce more fragments with higher kinetic energy, linked to the multifragmentation stage.

Contribution

It introduces the use of total charge in fragments as a new variable to analyze symmetry energy effects and distinguishes the stage of multifragmentation from secondary decay.

Findings

Mean number of fragments increases with neutron-richness.

Mean kinetic energy of fragments increases with neutron-richness.

Total charge in fragments helps quantify preequilibrium emission.

Abstract

Isospin e ffects on multifragmentation properties were studied thanks to nuclear collisions between di fferent isotopes of xenon beams and tin targets. It is shown that, in central collisions leading to multifragmentation, the mean number of fragments and their mean kinetic energy increase with the neutron-richness of the total system. Comparisons with a stochastic transport model allow to attribute the multiplicity increase to the multifragmentation stage, before secondary decay. The total charge bound in fragments is proposed as an alternate variable to quantify preequilibrium emission and to investigate symmetry energy e ffects.