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- Bauer, C., et al.
(author)
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Prolate shape of Ba-140 from a first combined Doppler-shift and Coulomb-excitation measurement at the REX-ISOLDE facility
- 2012
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In: Physical Review C (Nuclear Physics). - 0556-2813. ; 86:3
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Journal article (peer-reviewed)abstract
- Background: Quadrupole moments of excited nuclear states are important observables for geometrically interpreting nuclear structure in terms of deformed shapes, although data are scarce and sometimes ambiguous, in particular, in neutron-rich nuclides. Purpose: A measurement was performed for determining the spectroscopic quadrupole moment of the 2(1)(+) state of Ba-140 in order to clarify the character of quadrupole deformation (prolate or oblate) of the state in its yrast sequence of levels. Method: We have utilized a new combined technique of lifetime measurement at REX-ISOLDE and MINIBALL using the Doppler-shift attenuation method (DSAM) and a reorientation analysis of Coulomb-excitation yields. Results: On the basis of the new lifetime of tau(2(1)(+)) = 10.4(-0.8)(+2.2) ps the electric quadrupole moment was determined to be Q(2(1)(+)) = -0.52(34) eb, indicating a predominant prolate deformation. Conclusions: This finding is in agreement with beyond-mean-field calculations using the Gogny D1S force and with results from the Monte Carlo shell-model approach.
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