Motional narrowing and ergodic bands in excited superdeformed states of 194Hg

Araceli Lopez-Martens (1) , Thomas Døssing (2) , Teng Lek Khoo (3) , Masayuki Matsuo , Bent Herskind (2) , Torben Lauritsen (3) , Michael A. Carpenter (3) , Robert Janssens (3) , Greg Hackman , I-Yang Lee (4) , Augusto Macchiavelli (4) , Enrico Vigezzi (5) , K. Yoshida

1 CSNSM - Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse
2 NBI - Niels Bohr Institute [Copenhagen]
3 ANL - Argonne National Laboratory [Lemont]
4 LBNL - Lawrence Berkeley National Laboratory [Berkeley]
5 INFN - Istituto Nazionale di Fisica Nucleare, Sezione di Milano

The Egamma-Egamma coincidence spectra from the electromagnetic decay of excited superdeformed states in 194Hg reveal surprisingly narrow ridges, parallel to the diagonal. 100-150 excited bands are found to contribute to these ridges, which account for nearly all the unresolved E2 decay strength. Comparison with theory suggests that these excited bands have many components in their wavefunctions, yet they display remarkable rotational coherence. This phenomenon can be explained in terms of the combination of shell effects and motional narrowing.

Mots clés: nuclear structure; superdeformation; chaos; rotational damping; motional narrowing

Domaines: Physique Nucléaire Expérimentale [nucl-ex]

Araceli Lopez-Martens, Thomas Døssing, Teng Lek Khoo, Masayuki Matsuo, Bent Herskind, et al.. Motional narrowing and ergodic bands in excited superdeformed states of 194Hg. Physical Review Letters, 2008, 100, pp.102501. ⟨10.1103/PhysRevLett.100.102501⟩. ⟨hal-00326305⟩