1302.5327 (Zhen Zhang et al.)

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

Zhen Zhang, Lie-Wen Chen

We show that the neutron skin thickness $\Delta r_{np}$ of heavy nuclei is uniquely fixed by the symmetry energy density slope $L({\rho})$ at a subsaturation cross density $\rho_c \approx 0.11$ fm$^{-3}$ rather than at saturation density $\rho_0$, while the binding energy difference $\Delta E$ between a heavy isotope pair is essentially determined by the magnitude of the symmetry energy $E_{sym}}({\rho})$ at the same $\rho_c$. Furthermore, we find a value of $L({\rho_c})$ leads to a negative $E_{sym}({\rho_{0}})$-$L({\rho_{0}})$ correlation while a value of $E_{sym}({\rho_{c})}$ leads to a positive one. Using data on $\Delta r_{np}$ of Sn isotopes and $\Delta E$ of a number of heavy isotope pairs, we obtain simultaneously $E_{sym}({\rho_{c})}=26.65 \pm 0.20$ MeV and $L({\rho_c})= 46.0 \pm 4.5$ MeV at 95% confidence level, whose extrapolation gives $E_{sym}({\rho_{0}})=32.3 \pm 1.0$ MeV and $L({\rho_{0}})=45.2 \pm 10.0$ MeV.

View original: http://arxiv.org/abs/1302.5327