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HK: Fachverband Hadronen und Kerne

HK 67: Poster Session

HK 67.41: Poster

Donnerstag, 19. März 2009, 14:00–16:00, Audi-Max

Collective dipole response of proton-rich nuclei ³²Ar and ³⁴Ar. — •Olga Lepyoshkina¹ and Christoph Langer² — ¹Physik Department TU München, Garching — ²Institut für Kernphysik, Universität Frankfurt, Frankfurt am Main, Germany

The earlier observation of low-lying dipole strength in neutron rich nuclei and its interpretation with respect to basic nuclear properties (symmetry energy, skin thickness) initiated the investigation of this phenomenon in proton-rich nuclei. Macroscopically this strength could be explained with the resonant dipole oscillation of a proton skin against the isospin-symmetric core. For nuclei like ³²Ar the occurrence of pronounced dipole strength is predicted in the low-energy region between 8-10 MeV excitation energy. For the ³⁴Ar the pygmy strength is expected to drop sharply and vanish entirely for the N=Z nucleus ³⁶Ar.

The experiment S327 has been performed in August 2008 at the GSI Darmstadt in Cave C using the LAND reaction setup. Fragmentation of a 800 A MeV primary ³⁶Ar beam on a Be target was used to produce the radioactive isotopes ³⁴Ar and ³²Ar. After passing the FRS (Fragment Separator) the ions impinged on a Pb target. The dipole response is observed using the Coulomb excitation method in inverse kinematics. The concept and the experimental method will be shown in the context of the underlying physics case in ^32,34Ar.

This work was supported by GSI F&E and BMBF.