Neutron densities and the equation of state for neutron-rich matter

We present predictions for energies, proton and neutron rms radii, and neutron skins of some closed-shell nuclei based upon a microscopic model of the equation of state for asymmetric nuclear matter which is used as input for a mass formula. We employ realistic two-body forces and the Dirac-Brueckner-Hartree-Fock approach to nuclear matter. We compare with experimental information, when available, and point out the need for accurate determinations of neutron densities and skins.

Figure 1

Energy per nucleon $e$ as a function of the Fermi momentum $k_F$ and the neutron excess parameter $\alpha$.

Figure 2

Energy∕nucleon as a function of the Fermi momentum predicted with Bonn $A$ (solid line), Bonn $B$ (dotted line), and Bonn $C$ (dash-dot), for $\alpha =0$ (lower group) and $\alpha =0.4$ (upper group).

Figure 3

Neutron (a) and proton (b) density distributions for ${}^{40}\mathrm{Ca}$ obtained with three relativistic one-boson-exchange potentials. All calculations are DBHF.

Figure 4

As in Fig. 3, for ${}^{90}\mathrm{Zr}$.

Figure 5

As in Fig. 3, for ${}^{208}\mathrm{Pb}$.

Figure 6

As in Fig. 3, for ${}^{266}\mathrm{Pb}$.

Figure 7

Charge radii predicted with Bonn $A(+)$, Bonn $B(\times )$, and Bonn $C(*)$. The squares represent the experimental charge radii.

Figure 8

Neutron rms radii predicted with Bonn $A(+)$, Bonn $B(\times )$, and Bonn $C(*)$.

Figure 9

Neutron skins predicted with Bonn $A(+)$, Bonn $B(\times )$, and Bonn $C(*)$.

Figure 10

Neutron skins predicted with Bonn $A(+)$, Bonn $B(\times )$, and Bonn $C(*)$ for Sn isotopes. Data from Ref. 14.

Figure 11

Total matter density (a) and asymmetry (b) predicted with Bonn $B$ for ${}^{208}\mathrm{Pb}$ (solid line) and ${}^{266}\mathrm{Pb}$ (dashed line).

Figure 12

Neutron (a) and proton (b) densities for ${}^{208}\mathrm{Pb}$ predicted with a BHF calculation (dashed line) compared with the corresponding DBHF predictions (solid line).