Isocaling and the Symmetry Energy in the Multifragmentation Regime of Heavy Ion Collisions

TL;DR

This study investigates the symmetry energy in heavy ion collisions by analyzing isotope ratios and comparing experimental data with AMD model calculations, revealing insights into nuclear matter properties during multifragmentation.

Contribution

It introduces a method to extract the symmetry energy coefficient to temperature ratio using isoscaling and compares experimental results with AMD model predictions.

Findings

Experimental $a_{sym}/T$ values agree with AMD calculations.

Significant differences found between experimental values and primary AMD fragment yields.

Results enhance understanding of symmetry energy behavior in nuclear multifragmentation.

Abstract

The ratio of the symmetry energy coefficient to temperature, $a_sym/T$, in Fermi energy heavy ion collisions, has been experimentally extracted as a function of the fragment atomic number using isoscaling parameters and the variance of the isotope distributions. The extracted values have been compared to the results of calculations made with an Antisymmetrized Molecular Dynamics (AMD) model employing a statistical decay code to account for deexcitation of excited primary fragments. The experimental values are in good agreement with the values calculated but are significantly different from those characterizing the yields of the primary AMD fragments.