The lifetimes of five levels of the two-quasineutron band in 128Ba populated via the 116Cd(16O,4n) reaction were measured for the first time by means of the recoil-distance Doppler-shift method. For the data-analysis, a new version of the differential decay-curve method in singles-like mode was developed which takes into account the velocity distribution of the recoils and the effect of the Doppler-shift attenuation in the stopper. The high values of 〈K2〉 and View the MathML source characterising the band are confirmed by the determined B(E2,I→I−2) and B(M1,I→I−1) transition strengths. At the same time, the rigid-rotor model is not able to describe the behaviour of the experimental B(E2,I→I−1) and B(M1,I→I−1) values. A new theoretical effort seems to be needed for a consistent explanation of the intraband transition strengths within two-quasiparticle bands in γ-soft nuclei.
On the two-quasineutron rotational band in Ba
LUNARDI, SANTO;PAVAN, PIETRO;
2000
Abstract
The lifetimes of five levels of the two-quasineutron band in 128Ba populated via the 116Cd(16O,4n) reaction were measured for the first time by means of the recoil-distance Doppler-shift method. For the data-analysis, a new version of the differential decay-curve method in singles-like mode was developed which takes into account the velocity distribution of the recoils and the effect of the Doppler-shift attenuation in the stopper. The high values of 〈K2〉 and View the MathML source characterising the band are confirmed by the determined B(E2,I→I−2) and B(M1,I→I−1) transition strengths. At the same time, the rigid-rotor model is not able to describe the behaviour of the experimental B(E2,I→I−1) and B(M1,I→I−1) values. A new theoretical effort seems to be needed for a consistent explanation of the intraband transition strengths within two-quasiparticle bands in γ-soft nuclei.Pubblicazioni consigliate
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