The role of Fock terms on nuclear symmetry energy and its slope parameter in a relativistic framework

We study the effect of Fock terms on the nuclear symmetry energy, E_sym, and its slope parameter, L, with the Lorentz-covariant decomposition of nucleon self-energies in a relativistic framework. Since E_sym can be separated into the kinetic and potential terms using the Hugenholtz-Van Hove theorem, it is possible to compare their density dependence of theoretical calculations with the experimental results. It is found that the Fock contribution suppresses E_sym and L at high densities, and that the constraint from the heavy-ion collision data is in favor of the present result including the Fock effect. (author)