High Spin Physics 2001, Warsaw, February 6-10, 2001



Abstract No: 007
Submitted on: 19 Dec 2000, 19:19 GMT
Title: Wobbling motion in 16371Lu92 - Understanding of observed properties
Author(s): Ikuko Hamamoto
Affiliation(s): Division of Mathematical Physics, LTH, University of Lund, P.O.Box 118, S-22100 Lund, Sweden



Though nuclear wobbling motion, which is a unique feature of the rotation of a triaxial nuclear shape, has been theoretically discussed for years (for example, see ref. [1]), it has never been experimentally identified with conclusive evidence. For nuclei with N$\sim$94 and Z$\sim$71-72, the total energy surface calculations [2] predict stable triaxial shapes with large quadrupole deformation ( $\varepsilon$$\sim$0.38 and $\gamma$$\sim$$\pm$20$^{\circ}$) for all parity and signature in a certain region of angular momentum. Using the fusion evaporation reaction 139La(29Si,5n)163Lu with a beam energy of 152 MeV, two presumably triaxial super deformed (TSD) bands have been observed. The possible assignment of the excited TSD band as a wobbling mode built on the yrast TSD band is reported [3].

A careful analysis of all observed quantities (the level scheme, spin-alignments, electromagnetic properties, etc.) of those TSD bands is now available [4]. I plan to explain our understanding of the result of the analysis in terms of a wobbling mode built on the aligned i13/2 proton, which is suggested using particle-rotor model calculations in ref. [5]. We believe that we have now a convincing evidence for the observation of nuclear wobbling motion.

Bibliography

1
A. Bohr and B. R. Mottelson, Nuclear Structure, Vol.II, (Benjamin, New York, 1975), Chap. 4, p. 190.

2
H. Schnack-Petersen et al., Nucl. Phys. A594, 175 (1995).

3
S. W. Odegaard, G.B.Hagemann et al., Proc. of International Conference at MSU, Aug., 2000 ; to be published in a special issue of Nucl. Phys. A.

4
S. W. Odegaard, G.B.Hagemann et al., contribution to this conference.

5
I. Hamamoto, Phys. Lett. B193, 399 (1987).

\fbox{ Invited talk. }

High Spin Conference
2000-12-23