Mainz 2012 – wissenschaftliches Programm

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HK: Fachverband Physik der Hadronen und Kerne

HK 28: Struktur und Dynamik von Kernen

HK 28.1: Gruppenbericht

Mittwoch, 21. März 2012, 14:00–14:30, P 4

Investigation of octupole vibrational states in medium mass nuclei — •Sorin Pascu, Michael Elvers, Janis Endres, Andreas Hennig, Simon Pickstone, and Andreas Zilges — Institut für Kernphysik, Universität zu Köln

The experimental and theoretical evidence for the presence of octupole vibrational states in ¹⁴⁶Sm and ¹⁵⁰Nd is presented. The first nucleus which is located only two neutrons and two protons away from the N=82 shell and Z=64 subshell closures has been investigated by means of the ¹⁴³Nd(α,n) and ¹⁴⁴Nd(α,2n) fusion-evaporation reactions. The structure of the possible candidates for a 2⁺⊗3⁻ quadrupole-octupole multiplet are discussed in terms of the harmonic vibrational model and interpreted in terms of the Interacting Boson Approximation in the spdf boson space (IBA-spdf). The latter nucleus which is a quadrupole deformed nucleus was investigated via inelastic proton scattering which is an excellent method to excite natural parity states. Using this method, B(E1) ratios of the decaying transitions for the octupole vibrational states were determined and compared to the Alaga rule and with the IBA-spdf model. A general good agreement was found between experimental data and theoretical calculations.

Supported by the DFG (ZI 510/4-1). A.H. and S.P. are members of the Bonn-Cologne Graduate School of Physics and Astronomy.