STUDIES OF ELECTRIC DIPOLE RESPONSE IN NUCLEI USING THE SCATTERING OF POLARIZED PROTONS

The electric dipole (E1) response of Pb-208 has been precisely determined by proton inelastic scattering measurement at very forward angles. The electric dipole polarizability, which is an inversely energy-weighted sum-rule of the electric dipole strength, has been extracted as 20.1 +/- 0.6 fm(3). The data has been used to constrain the neutron skin thickness of Pb-208 as 0.168 +/- 0.22 fm and the slope parameter of the symmetry energy as L = 46 +/- 15 MeV. The determination of the slope parameter is important for nuclear physics as well as for astrophysical simulations related to neutron stars. DOI:10.5506/APhysPolB.44.571