Effects of medium-induced $\rho -\omega$ meson mixing on the equation of state in isospin-asymmetric nuclear matter

Abstract

We reexamine effects of the $\rho -\omega$ meson mixing mediated by nucleon polarizations on the symmetry energy in isospin-asymmetric 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 Mean-Field 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 lowest-order calculations, we also solve the RPA equation for the $\rho -\omega$ mixing. In this case, it is found that the symmetry energy is not only significantly softened by the $\rho -\omega$ mixing at supra-saturation densities, similar to the lowest-order $\rho -\omega$ mixing, but interestingly also softened at subsaturation densities. In addition, the softening of the symmetry energy at subsaturation densities can be partly suppressed by the nonlinear self-interaction of the $\sigma$ meson.

Significant changes made. Accepted version to appear in PRC (2009)

References in corpus (7)

• Circumstantial evidence for a soft nuclear symmetry energy at supra-saturation densities
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Cited by in corpus (3)

• Probing nuclear symmetry energy at high densities using pion, kaon, eta and photon productions in heavy-ion collisions
• The impact of charge symmetry and charge independence breaking on the properties of neutrons and protons in isospin-asymmetric nuclear matter
• ${\rho }^0-\omega$ mixing in the presence of a weak magnetic field