Evidence for octupole vibration in the triaxial superdeformed well of {sup 164}Lu.
High-spin states in {sup 164}Lu were populated in the {sup 121}Sb({sup 48}Ca,5n) reaction at 215 MeV and {gamma}-ray coincidences were measured with the Gammasphere spectrometer. Through this experiment the eight known triaxial superdeformed bands in {sup 164}Lu could be confirmed. Some of these bands were extended to higher as well as to lower spins. Evidence is reported for the first time for weak {delta}I=1,E1 transitions linking TSD3 and TSD1. This observation may imply coupling to octupole vibrational degrees of freedom. The decay mechanism is different from the one observed in the neighboring even-N isotopes, which exhibit wobbling excitations built on the {pi}i{sub 13/2} structure with E2(M1),{delta}I=1 interband decay. An additional sequence decaying at high spin into TSD1 was observed up to I{sup {pi}}=(50{sup -}). This band has a constant dynamic moment of inertia of {approx}70({Dirac_h}/2{pi}){sup 2}MeV{sup -1} and an alignment that is {approx}2({Dirac_h}/2{pi}) larger than that found for TSD1. A revision of the assumed spin-parity-assignment of TSD2 is based on the observed decay-out to normal-deformed structures. The parity and signature quantum numbers of TSD2 are now firmly assigned as ({pi},{alpha})=(+,0), in disagreement with the former assignment of ({pi},{alpha})=(-,1), which was based on the assumption that TSD2 is the signature partner of TSD1. TSD1 and TSD2 show an alignment gain at ({Dirac_h}/2{pi}){omega}{approx}0.67 and 0.60 MeV, respectively. In TSD1 the involvement of the j{sub 15/2} neutron orbital is suggested to be responsible for the high-frequency crossing.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC); Danish Science Foundation; German BMPF
- DOE Contract Number:
- DE-AC02-06CH11357
- OSTI ID:
- 914957
- Report Number(s):
- ANL/PHY/JA-58626; PRVCAN; TRN: US0804858
- Journal Information:
- Phys. Rev. C, Vol. 75, Issue 2007; ISSN 0556-2813
- Country of Publication:
- United States
- Language:
- ENGLISH
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