Signature inversion caused by triaxiality in 72Br and band termination in 73Br

Schwengner, R.; Plettner, C.; Schnare, H.; Käubler, L.; Dönau, F.; Ragnarsson, I.; Afanasjev, A. V.; Algora, A.; Angelis, G. de; Gadea, A.; Napoli, D. R.; Eberth, J.; Steinhardt, T.; Thelen, O.; Hausmann, M.; Müller, A.; Jungclaus, A.; Lieb, K. P.; Jenkins, D. G.; Wadsworth, R.; Wilson, A. N.; Frauendorf, S.

Signature inversion caused by triaxiality in 72Br and band termination in 73Br

Schwengner, R.; Plettner, C.; Schnare, H.; Käubler, L.; Dönau, F.; Ragnarsson, I.; Afanasjev, A. V.; Algora, A.; de Angelis, G.; Gadea, A.; Napoli, D. R.; Eberth, J.; Steinhardt, T.; Thelen, O.; Hausmann, M.; Müller, A.; Jungclaus, A.; Lieb, K. P.; Jenkins, D. G.; Wadsworth, R.; Wilson, A. N.; Frauendorf, S.

High-spin states in 72Br and 73Br were studied with the EUROBALL III spectrometer.
The negative-parity band observed in 72Br displays a signature inversion around spin I = 16. Fully consistent cranked Nilsson-Strutinsky calculations show that this signature inversion can only be understood if the nuclear shape evolves from a triaxial shape with rotation around the intermediate axis at low spin through a collective prolate shape to a triaxial shape with rotation around the shortest principal axis at high spin. Rotational bands in 73Br
were observed up to spins of I = 65/2 at excitation energies of 26 MeV. Cranked Nilsson-Strutinsky calculations indicate that one of the negative-parity bands terminates at spin 63/2. Since this spin coincides with the maximum spin observed in the corresponding experimental band, we conclude that we observed this band up to its termination.

Keywords: Nuclear structure experiments; Nuclear models; EUROBALL detector

Contribution to HZDR-Annual report
Proceedings of the Conference Bologna 2000 - Structure of the Nucleus at the Dawn of the Century, 29 May - 3 June, 2000, Bologna, Italy

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