7-11 July 2014
Africa/Johannesburg timezone
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Octupole correlations and Collective Couplings in the rare earth nucleus 154Dy

Presented by Mr. George ZIMBA on 8 Jul 2014 from 11:30 to 11:50
Type: Oral Presentation
Session: NPRP
Track: Track B - Nuclear, Particle and Radiation Physics


There is currently less information available on the structure of <sup>154</sup>Dy at low spins. The question still remains whether at low spins the structure exhibits permanent octupole deformation [1] or aligned tidal wave octupole phonons [2]. Intermediate spins of the nucleus <sup>154</sup>Dy were populated via the <sup>155</sup>Gd (3He, 4n) <sup>154</sup>Dy reaction at 45 MeV at iThemba LABS using AFRODITE array spectrometer. The even-even nucleus <sup>154</sup>Dy with 6 neutrons and 2 protons outside the closed shell is nearly spherical. The N = 88 isotones have remarkable features; They are at a peak in the |M(E3)| <sup>2</sup> transition strength of 0<sup>+</sup><sub>1</sub> → 3<sup>-</sup><sub>1</sub> transitions for even-even nuclei as a function of neutron number usually called octupole vibration [34]. This was first stated by Chasman theoretically [1] whereby the first excited states in some nuclei have an octupole deformed first excited state with a quadruple deformation in the ground state and shown experimentally for <sup>154</sup>Gd<sub>88</sub> [4]. The strong E3 properties have been described and explained as due to the nearness of &Delta J<sup> &pi</sup>=3<sup> -</sup> shell model orbits to the Fermi surface. They also have very strong E0 transitions from the band built on the 0 <sup>+</sup><sub>2</sub> states to the ground state bands [3, 5]. The measurements we have made on <sup>154</sup>Dy are motivated by the findings from our studies of the isotones <sup>152</sup>Gd and <sup>150</sup>Sm from [6] where we observed octupole correlations between the 0 <sup>+</sup><sub>2</sub> states and the lowest-lying negative parity band, commonly known as the octupole band. References [1] R. R. Chasman, Phys. Rev. Lett. 42, 630 (1979). [2] S. Frauendorf, Phys. Rev. C77, 021304(R) (2008). [3] S. P. Bvumbi et al., Phys. Rev. C 87, 044333 (2013). [4] S P Bvumbi, “Spin and Parity Assignment in 152Gd Investigating Octupole Structures”; MSc thesis, University of Western Cape (2008). [5] S. Frauendorf, Y. Gu, J. Sun, Tidal waves as yrast states in transitional nuclei (2007). [6] S. P. Bvumbi, “Investigation of octupole correlations and collective couplings in the rare earth nucleus 150Sm” PhD thesis, University of Johannesburg, (2013).






SUZAN PHUMUDZO BVUMBI University of Johannesburg suzan@tlabs.ac.za




Room: D Les 101

Primary authors