Evidence of the Finite Boson Number from Lifetime Measurements in 78Kr and 79Rb
At the first Erice Meeting on Interacting Bosons, Gelberg and Kaup1 presented an interpretation of the ground state and γ bands of the even Kr isotopes in terms of IBA-2 2. They recognized that the spectra change from that of the rather strongly deformed 74,76 Kr to the γ-unstable shapes of the 80,82 Kr isotopes. These fits required remarkably few force constants; furthermore, it was found that all interaction parameters remained essentially constant, except for the quadrupole term Xπ and the boson number Nπ which varied linearly with the neutron number.
KeywordsFeeding Time Ground State Band Boson Number Negative Parity Band Recoil Distance
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- 2.T.Otsuka, A.Arima, F.Iachello, and I.Talmi, Phys. Lett. 76B: 139 (1979).Google Scholar
- 3.H.P.Hellmeister, U.Kaup, J.Keinonen, K.P.Lieb, R.Rascher, R.Ballini, J.Delaunay, and H.Dumont, Phys. Lett. 85B:34 (1979) and Nucl. Phys. A332: 241 (1979).Google Scholar
- 4.L.Funke, priv. communication.Google Scholar
- 6.H.P.Hellmeister, K.P.Lieb, and W.F.J.Müller, Nucl. Phys. A307:515 (1978) and to be publ.Google Scholar
- 8.F.Stephens, Rev. Mod. Phys. 47:43 (1975). J. Meyer-terVehn, Nucl. Phys. A249:111, 141 (1975). H.Toki and A.Faessler, Phys. Lett. 63B: 121 (1976).Google Scholar
- 9.F.Iachello and O.Scholten, Phys.Rev.Lett. 43:679(1979); O.Scholten, thesis University of Groningen, unpubl.Google Scholar
- 10.An improved fit of the positive parity states in 78Kr in terms of IBA-1 has been achieved for the parameters: = 0.41, C0 = 0.26, C2 = −0.14, C4 = 0.15, v0 = −0.24, v2 =−0.10 Mev; effective E2 charges q2 = 8.6 efm2, q2 = − 16.0 efm2.Google Scholar
- 11.In the calculations of the continuum feeding times, El transitions of 5.10−4 Wu, statistical E2 transitions of 1 Wu as well as collective E2 transitions of 200 Wu were assumed. When changing the latter quantity to 50 Wu the feeding times increased somewhat, but still are considerably smaller than the lifetimes measured.Google Scholar