2018 Impact factor 2.481
Hadrons and Nuclei
Eur. Phys. J. A 3, 17-20

First observation of excited states in 184Pb: spectroscopy beyond the neutron mid-shell

J.F.C. Cocks1 - M. Muikku1 - W. Korten2 - R. Wadsworth3 - S. Chmel4 - J. Domscheit4 - P.T. Greenlees5 - K. Helariutta1 - I. Hibbert3 - M. Houry2 - D. Jenkins3 - P. Jones1 - R. Julin1 - S. Juutinen1 - H. Kankaanpää1 - H. Kettunen1 - P. Kuusiniemi1 - M. Leino1 - Y. Le Coz2 - R. Lucas2 - E. Mergel4 - R.D. Page5 - A. Savelius1 - W. Trzaska1

1 Accelerator Laboratory, Department of Physics, University of Jyväskylä, 40351 Jyväskylä, Finland
2 DAPNIA/SPhN CEA-Saclay, France
3 Department of Physics, University of York, Heslington, York YO1 5DD, United Kingdom
4 Institut für Strahlen- und Kernphysik, Universität Bonn, D-53115 Bonn, Germany
5 Oliver Lodge Laboratory, Department of Physics, University of Liverpool, Liverpool L69 7ZE, United Kingdom

Received: 19 May 1998 / Revised version: 1 July 1998 Communicated by D. Schwalm

Abstract
Excited states have been identified for the first time in 184Pb, the first even-even Pb isotope beyond the 82<N<126 mid-shell, using the recoil-decay tagging (RDT) technique. A collective band built on the first-excited 2+ state has been observed. This resembles those seen in 186,188Pb and the Hg isotones, and can thus be associated with a prolate-deformed shape. Variable moment of inertia (VMI) fits of the prolate 0+ level energies in 184,186,188Pb indicate that the minimum appears at N=103, the same neutron number at which the corresponding minimum in Hg isotopes is observed.

PACS
21.60.Ev Collective models - 23.20.-g Electromagnetic transitions - 25.70.gh Compound nucleus - 23.60.+e $\alpha$ decay

Author for correspondance: James.Cocks@phys.jyu.fi


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