Effects of medium on nuclear properties in multifragmentation

Abstract

In multifragmentation of hot nuclear matter, properties of fragments embedded in a soup of nucleonic gas and other fragments should be modified as compared with isolated nuclei. Such modifications are studied within a simple model where only nucleons and one kind of heavy nuclei are considered. The interaction between different species is described with a momentum-dependent two-body potential whose parameters are fitted to reproduce properties of cold isolated nuclei. The internal energy of heavy fragments is parametrized according to a liquid-drop model with density-and temperature-dependent parameters. Calculations are carried out for several subnuclear densities and moderate temperatures, for isospin-symmetric and asymmetric systems. We find that the fragments get stretched due to interactions with the medium and their binding energies decrease with increasing temperature and density of nuclear matter.

Symmetry energy of warm nuclear systems

“…(7) has been used [28,29] in the experimental determination of the values of the symmetry coefficients of warm dilute nuclear matter. For application in core-collapse supernova simulations, it is more insightful to have understanding about the temperature dependence of the symmetry energy of isolated nuclei or nuclei embedded in a nucleonic medium [30]. In a limited temperature domain (T ≤ 2 MeV), calculations of the symmetry energy coefficients of atomic nuclei have been attempted in a schematic model by Donati et al, [31].…”

A comparative study of statistical models for nuclear equation of state of stellar matter

“…Other modifications are now under intensive theoretical and experimental investigation in multifragmentation reactions, for example, a decrease of the symmetry energy of fragments [46,47,48], and reduction of the binding energies of light clusters [56,87,88] in-medium. A calculation within a selfconsistent microscopic approach has been performed recently in [89]. Presently, we can only declare significant differences between mass distributions of SMSM, HS and FYSS models, which use different assumptions on properties of fragments, especially at low electron fractions, low temperatures and high densities.…”

Thermal properties of the nuclear surface

“…where T c (X) is the critical temperature for infinite nuclear matter of isospin asymmetry X, defined as X = (ρ n − ρ p )/(ρ n + ρ p ) where ρ n and ρ p are the neutron and proton densities (for SINM, the definition of asymmetry is somewhat more subtle and given later). Since then, numerous calculations have been done to understand properties of hot nuclear matter [5,6,17] with this form of temperature-dependent interface energy. The scenario for finite nuclei is, however, different.…”

“…Since then, numerous calculations have been done to understand properties of hot nuclear matter [5,6,17] with this form of temperature-dependent interface energy. The scenario for finite nuclei is, however, different.…”