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 Pb-208 (R-skin(208)) provides a stringent laboratory constraint on the density dependence of the symmetry energy. In turn, an improved value of R(skin)(208 )has been reported recently by the PREX collaboration. Exploiting the strong correlation between R-skin(208) 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.

Automated summary

Laboratory experiments sensitive to the equation of state of neutron rich matter in the vicinity of nuclear saturation density provide crucial data connecting terrestrial experiments to astronomical observations. The neutron skin thickness of Pb-208 further constrains the density dependence of the symmetry energy. The impact of a stiff symmetry energy on critical neutron-star observables is studied.