Hierarchy in mid-rapidity fragmentation: mass, isospin, velocity correlations

TL;DR

This paper investigates the transition from nuclear multifragmentation to neck fragmentation in heavy-ion collisions, revealing hierarchy phenomena in fragment kinematics and their correlation with isospin dynamics to inform nuclear symmetry energy understanding.

Contribution

It introduces a microscopic transport model analysis of fragmentation hierarchy phenomena and their relation to isospin dynamics in semi-central heavy-ion collisions.

Findings

Hierarchy phenomena in fragment kinematics are observed.

Correlations between fragment observables and isospin dynamics are identified.

Results provide insights into the density dependence of nuclear symmetry energy.

Abstract

We present new features of the transition from nuclear multifragmentation to neck fragmentation in semi-central heavy-ion collisions at Fermi energies as obtained within a microscopic transport model, Stochastic Mean Field (SMF). We show that along this transition specific hierarchy phenomena of some kinematic observables associated with the intermediate mass fragments develop. Their correlations with the dynamics of isospin degree of freedom, predicted by our calculations, open new possibilities to learn about the density dependence of nuclear symmetry energy below saturation, as well as about the fragmentation mechanisms. Detailed results are presented for mass symmetric Sn + Sn reactions with different isospin content at 50A MeV .