Decomposition of nuclear symmetry energy based on Lorentz-covariant nucleon self-energies in relativistic Hartree-Fock approximation

Using the Lorentz-covariant decomposition of nucleon self-energies based on the Hugenholtz–Van Hove theorem, we study the effect of Fock terms on the nuclear symmetry energy and its slope parameter within relativistic Hartree-Fock approximation. It is found that the exchange contribution suppresses the nuclear symmetry energy and prevents the slope parameter from increasing monotonically at high densities. Furthermore, not only the isovector-vector (ρ) meson but also the isoscalar mesons (σ,ω) and pion give significant influence on the potential term of nuclear symmetry energy through the exchange diagrams. Keywords: Asymmetric nuclear matter, Nuclear symmetry energy, Relativistic Hartree-Fock approximation