Signature inversion caused by triaxiality and unpaired band crossings in 72Br

Plettner, Christina; Ragnarsson, Ingemar; Schnare, Harald; Schwengner, Ronald; Kauebler, Lutz; Doenau, Friedrich; Algora, Alejandro; Deangelis, Giaccomo; Napoli, Daniel; Gadea, Andres; Eberth, Juergen; Steinhardt, Thorsten; Thelen, Olaf; Hausmann, Marius; Mueller, Alexander; Jungclaus, Andrea; Lieb, Klaus Peter; Jenkins, David; Wadsworth, Robert; Wilson, Anna

Signature inversion caused by triaxiality and unpaired band crossings in 72Br

Plettner, C.; Ragnarsson, I.; Schnare, H.; Schwengner, R.; Kauebler, L.; Doenau, F.; Algora, A.; Deangelis, G.; Napoli, D.; Gadea, A.; Eberth, J.; Steinhardt, T.; Thelen, O.; Hausmann, M.; Mueller, A.; Jungclaus, A.; Lieb, K. P.; Jenkins, D.; Wadsworth, R.; Wilson, A.

High-spin states in 72Br were studied with the EUROBALL III spectrometer . The negative-parity band
observed in this experiment displays a signature inversion around spin I = 16. The interpretation within cranked Nilsson-Strutinsky approach shows that this signature pattern is a signal of a substantial triaxial shape change with increasing spin where the nucleus evolves from a triaxial shape with rotation around the intermediate axis at low spin
through an axially symmetric prolate one to a triaxial shape
but with rotation around the shortest principal axis at high spin.
This is the first case in which signature inversion was clearly related to varying gamma deformation.

Keywords: high-spin bands; signature inversion; gamma deformation; cranked calculations

Physical Review Letters Vol. 85 No. 12 18. September 2000 pp. 2454-2457

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