Abstract
Theoretical predictions of neutron-rich matter are especially timely, as they complement recent and planned experimental efforts. We discuss and critically examine modern predictions and recent measurements of the neutron skins in 48Ca and 208Pb. We point out problematic aspects that arise in conjunction with a stiff density dependence of the symmetry energy and the resulting thick skin in 208Pb. We emphasize that such thick skin is outside the boundaries of ab initio nuclear theory. We also demonstrate the dramatic impact on the slope of the symmetry energy from relaxing or abandoning the constraint of free-space nucleon–nucleon data.