Münster 2011 – wissenschaftliches Programm
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HK: Fachverband Physik der Hadronen und Kerne
HK 33: Struktur und Dynamik von Kernen - Poster
HK 33.1: Poster
Mittwoch, 23. März 2011, 14:00–16:00, Foyer Chemie
Parity Determination in 48Ca — •Friederike Schlüter1, Vera Derya1, Michael Elvers1, Janis Endres1, Gencho Rusev2, Deniz Savran3,4, Anton Tonchev2, and Andreas Zilges1 — 1Institut für Kernphysik, Universität zu Köln — 2Duke University, Durham, North Carolina, USA — 3ExtreMe Matter Institute EMMI and Research Division, GSI, Darmstadt — 4Frankfurt Institute for Advanced Studies FIAS
In many neutron-rich nuclei a concentration of electric dipole strength is located energetically below the giant dipole resonance. This so-called pygmy dipole resonance (PDR) is explained within various nuclear structure models by an oscillation of a neutron skin against a proton-neutron core. In order to study the structure of the PDR in medium mass nuclei, complementary scattering experiments with real photons and with α particles at around 34 MeV/nucleon on 48Ca have been performed recently [1]. The comparison of the results of these measurements revealed an unexpected behavior. Since almost all dipole states known from the nuclear resonance fluorescence experiment could be observed in the α scattering experiment as well, the strongest PDR state at 7.3 MeV could not be excited in the latter case. To confirm the assumption of Jπ=1− states, the parities of all known dipole states have been determined at the High-Intensity γ-Ray Source facility at the Duke University using 100% linearly polarized photons.
Supported by the DFG (ZI 510/4-1), the Bonn-Cologne Graduate School of Physics and Astronomy, and by EMMI.
[1] T. Hartmann et al., Phys. Rev. Lett. 93 (2004) 192501.