Constraining the symmetry energy at subsaturation densities using isotope binding energy difference and neutron skin thickness

By Zhen Zhang, Lie-Wen Chen. 2013

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Abstract We show that the neutron skin thickness Δ r n p of heavy nuclei is uniquely fixed by the symmetry energy density slope L ( ρ ) at a subsaturation cross density ρ c ≈ 0.11 fm − 3 rather than at saturation density ρ 0 , while the binding energy difference ΔE between a heavy isotope pair is essentially determined by the magnitude of the symmetry energy E sym ( ρ ) at the same ρ c . Furthermore, we find a value of L ( ρ c ) leads to a negative E sym ( ρ 0 ) – L ( ρ 0 ) correlation while a value of E sym ( ρ c ) leads to a positive one. Using data on Δ r n p of Sn isotopes and ΔE of a number of heavy isotope pairs, we obtain simultaneously E sym ( ρ c ) = 26.65 ± 0.20 MeV and L ( ρ c ) = 46.0 ± 4.5 MeV at 95 % confidence level, whose extrapolation gives E sym ( ρ 0 ) = 32.3 ± 1.0 MeV and L ( ρ 0 ) = 45.2 ± 10.0 MeV . The implication of these new constraints on the Δ r n p of 208Pb and the core–crust transition density in neutron stars is discussed.

Subfields: Astronomy and Astrophysics, Geophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/e9e6c89d7febbf8adb8d81e13e9d0d318fdd0d1e