Pygmy dipole resonance in Ce 140 via inelastic scattering of O 17

The γ decay from the high-lying states of 140Ce excited via inelastic scattering of 17O at a bombarding energy of 340 MeV was measured using the high-resolution AGATA- demonstrator array in coincidence with scattered ions detected in two segmented E-E silicon detectors. Angular distributions of scattered ions and emitted γ rays were measured, as well as their differential cross sections. The excitation of 1− states below the neutron separation energy is similar to the one obtained in reactions with the α isoscalar probe. The comparison between the experimental differential cross sections and the corresponding predictions using the distorted-wave Born approximation allowed us to extract the isoscalar component of identified 1− pygmy states. For this analysis the form factor obtained by folding microscopically calculated transition densities and optical potentials was used.