Contribution of isovector mesons to the symmetry energy in a microscopic model

We examine the potential energy contributions to the symmetry energy (in the parabolic approximation) arising from the isovector mesons, $\pi$, $\rho$, and $\delta$. The significance of a microscopic model that incorporates all important mesons is revealed. In particular, we demonstrate the importance of the pion for a realistic investigation of isospin-sensitive systems.

Figure 1

Contribution from the various mesons to the equation of state of (a) symmetric matter and (b) neutron matter.

Figure 2

The symmetry energy as predicted with Bonn A, B, and C.

Figure 3

Momentum dependence of the single-nucleon potentials in IANM $U_i$ ($i=p,n$) predicted with Bonn (a) A, (b) B, and (c) C. The total density is equal to 0.185 fm${}^{-3}$, and the isospin asymmetry parameter is 0.4. The momentum is given in units of the Fermi momentum, which is equal to 1.4 fm${}^{-1}$.