Probing the symmetry energy and the degree of isospin equilibrium

Abstract

The rapidity dependence of the single- and double- neutron to proton ratios of nucleon emission from isospin-asymmetric but mass-symmetric reactions Zr+Ru and Ru+Zr at energy range $100\sim 800$ A MeV and impact parameter range $0\sim 8$ fm is investigated. The reaction system with isospin-asymmetry and mass-symmetry has the advantage of simultaneously showing up the dependence on the symmetry energy and the degree of the isospin equilibrium. We find that the beam energy- and the impact parameter dependence of the slope parameter of the double neutron to proton ratio ($F_D$) as function of rapidity are quite sensitive to the density dependence of symmetry energy, especially at energies $E_b\sim 400$ A MeV and reduced impact parameters around 0.5. Here the symmetry energy effect on the $F_D$ is enhanced, as compared to the single neutron to proton ratio. The degree of the equilibrium with respect to isospin (isospin mixing) in terms of the $F_D$ is addressed and its dependence on the symmetry energy is also discussed.

10 pages, 2 figures

Cited by in corpus (7)

• Isospin effects on sub-threshold kaon production at intermediate energies
• Sensitivity of the transverse flow towards symmetry energy
• A model comparison of resonance lifetime modifications, a soft equation of state and non-Gaussian effects on $\pi -\pi$ correlations at FAIR/AGS energies
• Application of density dependent parametrization models to asymmetric nuclear matter
• Decomposition of sensitivity of the symmetry energy observables
• The influence of reconstruction criteria on the sensitive probes of the symmetry potential
• Difficulties in probing density dependent symmetry potential with the HBT interferometry