Giant dipole resonance as a quantitative constraint on the symmetry energy

The possible constraints on the poorly determined symmetry part of the effective nuclear Hamiltonians or effective energy functionals, i.e., the so-called symmetry energy S(ρ), are very much under debate. In the present work, we show that the value of the symmetry energy associated with Skyrme functionals, at densities {ρ} around 0.1 fm^-3, is strongly correlated with the value of the centroid of the Giant Dipole Resonance (GDR) in spherical nuclei. Consequently, the experimental value of the GDR in, e.g., ²⁰⁸Pb can be used as a constraint on the symmetry energy, leading to 23.3 MeV<S(ρ=0.1 fm^-3)<24.9 MeV.