Constraining the Symmetry Term in the Nuclear Equation of State at Sub-Saturation Densities and Finite Temperatures

TL;DR

This paper discusses methods to extract the symmetry energy coefficient from heavy-ion collision data, emphasizing the importance of source characterization and showing results are independent of fragment mass, indicating early reaction determination.

Contribution

It introduces a consistent approach to determine the symmetry energy coefficient at sub-saturation densities and finite temperatures from collision fragment yields.

Findings

Methods are consistent with proper source characterization.

Results are independent of fragment mass number.

Fate of fragments is decided early in the reaction.

Abstract

Methods of extraction of the symmetry energy (or enthalpy) coefficient to temperature ratio from isobaric and isotopic yields of fragments produced in Fermi-energy heavy-ion collisions are discussed. We show that the methods are consistent when the hot fragmenting source is well characterized and its excitation energy and isotopic composition are properly taken into account. The results are independent of the mass number of the detected fragments, which suggests that their fate is decided very early in the reaction.