Isobaric Yield Ratios and The Symmetry Energy In Fermi Energy Heavy Ion Reactions

Abstract

The relative isobaric yields of fragments produced in a series of heavy ion induced multifragmentation reactions have been analyzed in the framework of a Modified Fisher Model, primarily to determine the ratio of the symmetry energy coefficient to the temperature, $a_a/T$, as a function of fragment mass A. The extracted values increase from 5 to ~16 as A increases from 9 to 37. These values have been compared to the results of calculations using the Antisymmetrized Molecular Dynamics (AMD) model together with the statistical decay code Gemini. The calculated ratios are in good agreement with those extracted from the experiment. In contrast, the ratios determined from fitting the primary fragment distributions from the AMD model calculation are ~ 4 and show little variation with A. This observation indicates that the value of the symmetry energy coefficient derived from final fragment observables may be significantly different than the actual value at the time of fragment formation. The experimentally observed pairing effect is also studied within the same simulations. The Coulomb coefficient is also discussed.

10 pages, 12 figures

References in corpus (3)

• Experimental determination of the symmetry energy of a low density nuclear gas
• The Quantum Nature of a Nuclear Phase Transition
• Isospin dependent thermodynamics of fragmentation

Cited by in corpus (12)

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• Primary Isotope Yields and Characteristic Properties of the Fragmenting Source in Heavy-ion Reactions near the Fermi Energies
• Experimental reconstruction of primary hot isotopes and characteristic properties of the fragmenting source in the heavy ion reactions near the Fermi energy
• Analysis of fragment yield ratios in the nuclear phase transition
• Effects of sequential decay on collective flows and nuclear stopping power in heavy-ion collisions at intermediate energies
• Effect of neutron skin thickness on projectile fragmentation
• Reconstructed primary fragments and symmetry energy, temperature and density of the fragmenting source in ${}^{64}$Zn + ${}^{112}$Sn at 40 MeV/nucleon
• Isotopic ratio, isotonic ratio, isobaric ratio and Shannon information uncertainty
• Correlation and isospin dynamics of participant-spectator matter in neutron-rich colliding nuclei at 50 MeV/nucleon
• Statistical approach of nuclear multifragmentation with realistic nuclear equation of state