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Dynamical instabilities of warm npe matter: the delta meson effects

Authors: H. Pais, A. Santos, C. ProvidĂȘncia

Ref.: AIP Conference Proceedings 1231, 231-232 (2010)

Abstract: The effects of the delta meson on the dynamical instabilities of cold and warm nuclear and stellar matter at subsaturation densities are studied in the framework of relativistic mean-field hadron models (NL3, NLp and NLp delta) with the inclusion of the electromagnetic field. The crust-core transition density and pressure are obtained as a function of temperature of beta-equilibrium matter with and without neutrino trapping. The distillation effect is discussed. For beta-equilibrium matter with trapped neutrinos the pasta phase disappears for T> 13.2 MeV (NLp and NLp delta) or T> 11.6MeV (NL3). For neutrino free matter the non-homogeneous phase does not exist for T>3MeV. The delta meson has a larger effect in neutron rich matter, larger densities and smaller temperatures. It reduces the extension of the spinodal. The distillation effect is stronger for larger densities and smaller temperatures. The delta meson increases the distillation effect, for larger densities. NL3 predicts larger clusters compared with the other two parametrizations, and a smaller extension of the non-homogeneous phase for all temperatures. At the transition densities, the NLp and NLp delta predict clusters with the double of the size as compared with an intermediate density. Constraints at finite temperature on the EOS are required.