Covariant density functional theory for nuclear matter

Abstract

The EOS of nuclear matter is studied in the framework ofrelativistic density dependent hadron field theory (DDRH) and results are compared to the results of the phenomenological densitydependent approach DD-ME1 which is devised to fit theproperties of the symmetric nuclear matter around the normal nuclearmatter density . Nuclear interactions were described by a covariant density functional theory using baryons and mesons. In this work medium dependent modifications of the nuclear interactionsare taken into account with density dependent meson-baryon verticeswith momentum corrections. We showed that Lorentz invariance of theLagrangian, the covariance of the field equations andthermodynamical consistency require a formulation in terms of vertexfunctionals depending themselves on the field operators. Therelation of the DDRH vertex functionals to DB in-medium interactionsare discussed. Using relativistic mean-field approximation in DDRH, we have calculated the following properties of symmetric and asymmetric nuclear matter and pure neutron matter: energy density,pressure, binding energy, symmetry energy, effective nucleon mass,compressibility and speed of sound in nuclear medium as functions ofthe density and of the nuclear asymmetry parameter.