Implications of PREX-2 on the Equation of State of Neutron-Rich Matter

Laboratory experiments sensitive to the equation of state of neutron rich matter in the vicinity of nuclear saturation density provide the first rung in a "density ladder"that connects terrestrial experiments to astronomical observations. In this context, the neutron skin thickness of Pb208 (Rskin208) provides a stringent laboratory constraint on the density dependence of the symmetry energy. In turn, an improved value of Rskin208 has been reported recently by the PREX collaboration. Exploiting the strong correlation between Rskin208 and the slope of the symmetry energy L within a specific class of relativistic energy density functionals, we report a value of L=(106±37) MeV - which systematically overestimates current limits based on both theoretical approaches and experimental measurements. The impact of such a stiff symmetry energy on some critical neutron-star observables is also examined.