Mainz 2012 – scientific programme

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HK: Fachverband Physik der Hadronen und Kerne

HK 62: Nukleare Astrophysik

HK 62.4: Talk

Friday, March 23, 2012, 15:15–15:30, RW 2

Constraining mean-field models of the nuclear matter equation of state at low densities — •Maria Voskresenskaya and Stefan Typel — GSI, Darmstadt

The description of thermodynamical properties and the composition of dense nuclear matter for astrophysical applications requires the knowledge of the equation of state in a wide range of densities and temperatures. In this work we extend a generalized relativistic mean-field (gRMF) model with density dependent couplings by considering bound states of nuclei and two-nucleon scattering correlations as explicit degrees of freedom in the thermodynamical potential. These quasiparticles are characterized by medium dependent effective resonance energies with temperature dependent effective degeneracy factors. The model interpolates between the correct low-density limit, the model independent virial equation of state (VEoS), and the RMF description around nuclear saturation density where clusters are dissolved. From the comparison of the fugacity expansions of the VEoS and the gRMF model consistency relations between the quasiparticles properties, the nucleon-nucleon scattering phase shifts and the meson-nucleon couplings of the gRMF model at zero density are derived. Relativistic effects are found to be important at temperatures that are typical in astrophysical applications. The example of neutron matter is studied in detail for different temperatures.