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

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