Complete electric dipole response in 120Sn: a test of the resonance character of the pygmy dipole resonance

In high-resolution (p,p') experiments under 0 circle the complete B(E1) strength distribution can be studied in stable nuclei. At RCNP Osaka, Japan, angular distributions including 0 circle and polarization transfer observables for E1 excitations in 120Sn were measured in an excitation energy range of 5-25 MeV. The systematics of the pygmy dipole resonance in stable Sn isotopes has been recently studied at the S-DALINAC. From this study it was conclused that knowledge of the complete E1 response would be important to differentiate between relativistic an nonrelativistic QRPA models predicting largely different properties of the pygmy dipole resonance. Data analysis and first results on the E1 strength are presented.