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HK: Fachverband Physik der Hadronen und Kerne
HK 31: Struktur und Dynamik von Kernen
HK 31.1: Gruppenbericht
Dienstag, 5. März 2013, 14:00–14:30, HSZ-301
Probing the Character of the Pygmy Dipole Resonance — •Vera Derya1, Janis Endres1, Muhsin N. Harakeh2, Deniz Savran3,4, Mark Spieker1, Heinrich J. Wörtche2, and Andreas Zilges1 — 1Institut für Kernphysik, Universität zu Köln — 2Kernfysisch Versneller Instituut, Rijksuniversiteit Groningen, The Netherlands — 3ExtreMe Matter Institute EMMI and Research Division — 4Frankfurt Institute for Advanced Studies
In neutron-rich atomic nuclei, a concentration of low-lying E1 strength, the electric pygmy dipole resonance (PDR), was observed below and around the neutron-separation threshold. Its character was studied systematically by using different probes and techniques. Complementary to photon scattering experiments, for a set of nuclei the isoscalar probe of α particles at Eα=136 MeV was used in α-γ coincidence experiments at the Big-Bite Spectrometer [1]. The results permit a separation of the PDR from more isovector parts [1,2]. Most recently, a p-γ coincidence experiment at Ep=80 MeV was performed on 140Ce, previously studied by photons and α particles as a probe [2]. An overview of the particle-γ coincidence experiments and the systematics will be presented.
Supported by the DFG (ZI 510/4-2), EURONS, and the Alliance Program of the Helmholtz Association (HA216/EMMI). V.D. and M.S. are members of the Bonn-Cologne Graduate School of Physics and Astronomy.
[1] D. Savran et al., Phys. Rev. Lett. 97 (2006) 172502.
[2] J. Endres et al., Phys. Rev. Lett. 105 (2010) 212503.