Density dependence of the symmetry energy and the equation of state of isospin asymmetric nuclear matter
Abstract
The density dependence of the symmetry energy in the equation of state of isospin asymmetric nuclear matter is studied using the isoscaling of the fragment yields and the antisymmetrized molecular dynamic calculation. It is observed that the experimental data at low densities are consistent with the form of symmetry energy, E{sub sym}{approx_equal}31.6({rho}/{rho}{sub circle}){sup 0.69}, in close agreement with those predicted by the results of variational manybody calculation. A comparison of the present result with those reported recently using the NSCLMSU data suggests that the heavy ion studies favor a dependence of the form, E{sub sym}{approx_equal}31.6({rho}/{rho}{sub circle}){sup {gamma}}, where {gamma}=0.61.05. This constrains the form of the density dependence of the symmetry energy at higher densities, ruling out an extremely 'stiff' and 'soft' dependences.
 Authors:
 Cyclotron Institute, Texas A and M University, College Station, Texas 77843 (United States)
 Publication Date:
 OSTI Identifier:
 20995134
 Resource Type:
 Journal Article
 Resource Relation:
 Journal Name: Physical Review. C, Nuclear Physics; Journal Volume: 75; Journal Issue: 3; Other Information: DOI: 10.1103/PhysRevC.75.034602; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
 Country of Publication:
 United States
 Language:
 English
 Subject:
 73 NUCLEAR PHYSICS AND RADIATION PHYSICS; ASYMMETRY; COMPARATIVE EVALUATIONS; DENSITY; EQUATIONS OF STATE; HEAVY IONS; ISOSPIN; MANYBODY PROBLEM; MOLECULAR DYNAMICS METHOD; NUCLEAR MATTER; SYMMETRY; VARIATIONAL METHODS
Citation Formats
Shetty, D. V., Yennello, S. J., and Souliotis, G. A. Density dependence of the symmetry energy and the equation of state of isospin asymmetric nuclear matter. United States: N. p., 2007.
Web. doi:10.1103/PHYSREVC.75.034602.
Shetty, D. V., Yennello, S. J., & Souliotis, G. A. Density dependence of the symmetry energy and the equation of state of isospin asymmetric nuclear matter. United States. doi:10.1103/PHYSREVC.75.034602.
Shetty, D. V., Yennello, S. J., and Souliotis, G. A. Thu .
"Density dependence of the symmetry energy and the equation of state of isospin asymmetric nuclear matter". United States.
doi:10.1103/PHYSREVC.75.034602.
@article{osti_20995134,
title = {Density dependence of the symmetry energy and the equation of state of isospin asymmetric nuclear matter},
author = {Shetty, D. V. and Yennello, S. J. and Souliotis, G. A.},
abstractNote = {The density dependence of the symmetry energy in the equation of state of isospin asymmetric nuclear matter is studied using the isoscaling of the fragment yields and the antisymmetrized molecular dynamic calculation. It is observed that the experimental data at low densities are consistent with the form of symmetry energy, E{sub sym}{approx_equal}31.6({rho}/{rho}{sub circle}){sup 0.69}, in close agreement with those predicted by the results of variational manybody calculation. A comparison of the present result with those reported recently using the NSCLMSU data suggests that the heavy ion studies favor a dependence of the form, E{sub sym}{approx_equal}31.6({rho}/{rho}{sub circle}){sup {gamma}}, where {gamma}=0.61.05. This constrains the form of the density dependence of the symmetry energy at higher densities, ruling out an extremely 'stiff' and 'soft' dependences.},
doi = {10.1103/PHYSREVC.75.034602},
journal = {Physical Review. C, Nuclear Physics},
number = 3,
volume = 75,
place = {United States},
year = {Thu Mar 15 00:00:00 EDT 2007},
month = {Thu Mar 15 00:00:00 EDT 2007}
}

The symmetry energy is an important quantity in the equation of state of isospin asymmetric nuclear matter. This currently unknown quantity is key to understanding the structure of systems as diverse as the neutronrich nuclei and neutron stars. At TAMU, we have carried out studies, aimed at understanding the symmetry energy, in a variety of reactions such as, the multifragmentation of 40Ar, 40Ca + 58Fe, 58Ni and 58Ni, 58Fe + 58Ni, 58Fe reactions at 25  53 AMeV, and deepinelastic reactions of 86Kr + 124,112Sn, 64,58Ni (25 AMeV), 64Ni + 64,58Ni, 112,124Sn, 232Th, 208Pb (25 AMeV) and 136Xe + 64,58Ni,more »

Momentum, density, and isospin dependence of symmetric and asymmetric nuclear matter properties
Properties of symmetric and asymmetric nuclear matter have been investigated in the relativistic DiracBruecknerHartreeFock approach based on projection techniques using the Bonn A potential. The momentum, density, and isospin dependence of the optical potentials and nucleon effective masses are studied. It turns out that the isovector optical potential depends sensitively on density and momentum, but is almost insensitive to the isospin asymmetry. Furthermore, the Dirac mass m{sub D}* and the nonrelativistic mass m{sub NR}* which parametrizes the energy dependence of the single particle spectrum, are both determined from relativistic DiracBruecknerHartreeFock calculations. The nonrelativistic mass shows a characteristic peak structure atmore » 
Effects of mediuminduced {rho}{omega} meson mixing on the equation of state in isospinasymmetric nuclear matter
We reexamine effects of the {rho}{omega} meson mixing mediated by nucleon polarizations on the symmetry energy in isospinasymmetric nuclear matter. Taking into account the rearrangement term neglected in previous studies by others, we evaluate the {rho}{omega} mixing angle in a novel way within the relativistic meanfield models with and without chiral limits. It is found that the symmetry energy is significantly softened at high densities contrary to the finding in earlier studies. As the first step of going beyond the lowestorder calculations, we also solve the Dyson equation for the {rho}{omega} mixing. In this case, it is found that themore » 
Density dependence of the symmetry energy and the nuclear equation of state: A dynamical and statistical model perspective
The density dependence of the symmetry energy in the equation of state of isospin asymmetric nuclear matter is of significant importance for studying the structure of systems as diverse as the neutronrich nuclei and the neutron stars. A number of reactions using the dynamical and the statistical models of multifragmentation, and the experimental isoscaling observable, are studied to extract information on the density dependence of the symmetry energy. It is observed that the dynamical and the statistical model calculations give consistent results assuming the sequential decay effect in dynamical model to be small. A comparison with several other independent studiesmore »