Bonn 2010 – wissenschaftliches Programm
HK 63.5: Vortrag
Freitag, 19. März 2010, 15:30–15:45, HG II
Complete electric dipole response in 120Sn: a test of the resonance character of the pygmy dipole resonance — •Anna Maria Heilmann — TU Darmstadt, Germany
In high-resolution (p→,p→′) experiments under 0∘ the complete B(E1) strength distribution can be studied in stable nuclei. At the Research Center of Nuclear Physics in Osaka, Japan, the cross sections under 0∘−4∘ and observables for the polarization transfer of E1 and M1 excitations in 120Sn were measured in an excitation energy range of 5−25 MeV. The systematics of the pygmy dipole resonance (PDR) in stable tin isotopes has been recently studied at the superconductiong linear accelerator S-DALINAC in Darmstadt . From this study it was concluded 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. From the present measurement the whole B(E1) strength distribution and the branching ratios of the PDR to ground state can be extracted. The analysis procedure and first results on the E1 strength will be presented .
 B.Özel, J.Enders, H.Lenske, P. von Neumann-Cosel, I.Poltoratska, V.Yu. Ponomarev, A.Richter, D.Savran, and N.Tsoneva, submitted to Phys. Lett. B (2009).
⋆ Supported by the DFG through SFB 634 and 446JAP 113/267/0-2.