2018 Impact factor 2.481
Hadrons and Nuclei


Eur. Phys. J. A 10, 13-19

New excited superdeformed bands in heavy $\mathsf{Pb}$ nuclei: Clue for an octupole softness near the $\mathsf{N=118}$ gap at large deformation

A. Prévost1, N. Buforn1, A. Astier1, R. Duffait1, M. Meyer1, S. Perriès1, N. Redon1, O. Stézowski1, A. Bauchet2, I. Deloncle2, M.G. Porquet2, A. Görgen3, H. Hübel3, E. Mergel3, S. Neumann3, D. Roßbach3, N. Nenoff3, G. Schönwaßer3, A.N. Wilson4, R. Lucas5, F.A. Beck6, D. Curien6, G. Duchêne6, B.J.P. Gall6, N. Kintz6, J.P. Vivien6 and D.M. Cullen7

1  IPN Lyon, IN2P3/CNRS, Université Lyon-1, F-69622 Villeurbanne Cedex, France
2  CSNSM Orsay, IN2P3/CNRS, Université Paris-Sud, F-91405 Orsay Campus, France
3  Institut für Strahlen- und Kernphysik, Universität Bonn, Nussallee 14-16, D-53115 Bonn, Germany
4  Department of Physics, University of York, York Y01 5DD, United Kingdom
5  CEA/Saclay, DAPNIA/SPhN, F-91191 Gif sur Yvette, France
6  IReS Strasbourg, IN2P3/CNRS, Université Louis Pasteur, F-67037 Strasbourg Cedex 2, France
7  Oliver Lodge Laboratory, Department of Physics, University of Liverpool, Liverpool L69 7ZE, United Kingdom

astier@ipnl.in2p3.fr

(Received: 20 December 2000 Communicated by D. Schwalm )

Abstract
We report the identification of six new superdeformed (SD) bands in 197,198Pb observed with the EUROBALL IV spectrometer. The results are interpreted in the framework of cranked Hartree-Fock calculations with approximate projection on the particle number by means of the Lipkin-Nogami method. A mixing between quasi-particle excitations and an octupole vibration is suggested in the two SD isotopes. We have estimated the ordering of the neutron valence orbitals and confirm indirectly a N=118 SD gap.

PACS
21.10.Re - Collective levels.
21.60.Ev - Collective models.
23.20.Lv - Gamma transitions and level energies.
27.80.+w - 190 $\leq A \leq 219$ .

© Società Italiana di Fisica, Springer-Verlag 2001