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Lifetime measurements in the transitional nucleus 138Gd
Procter M.G., Cullen D.M., Ruotsalainen P., Braunroth T., Dewald A. et al
Physical Review C 84 (2011) 24314 - http://hal.in2p3.fr/in2p3-00761180
Physique/Physique Nucléaire Expérimentale
Lifetime measurements in the transitional nucleus 138Gd
M. G. Procter, D. M. Cullen, P. Ruotsalainen, T. Braunroth, A. Dewald, C. Fransen, T. Grahn, P. T. Greenlees, M. Hackstein, K. Hauschild1, U. Jakobsson, P. M. Jones, R. Julin, S. Juutinen, S. Ketelhut, A. Lopez-Martens1, M. Leino, J. Litzinger, P. J. R. Mason, P. Nieminen, P. Peura, P. Rahkila, M. W. Reed, S. Rice, S. Rinta-Antilla, W. Rother, M. Sandzelius, J. Sarén, C. Scholey, J. Sorri, M. J. Taylor2, J. Uusitalo, A. Vitturi, Y. Shi, F. R. Xu
1 :  CSNSM - Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse
CNRS : UMR8609 – IN2P3 – Université Paris XI - Paris Sud
batiments 104 et 108 - 91405 Orsay Campus
2 :  Department of Physics
Utah State University
Lifetime measurements have been made in the ground-state band of the transitional nucleus 138Gd from coincidence recoil-distance Doppler-shift data. 138Gd nuclei were produced using the 106Cd (36Ar, 2p2n) reaction with a beam energy of 190 MeV. Reduced transition probabilities have been extracted from the lifetime data collected with the Köln plunger placed at the target position of the JUROGAM-II array. The B(E2) values have been compared with predictions from X(5) critical-point calculations, which describe the phase transition between vibrational and axially symmetric nuclear shapes, as well as with IBM-1 calculations at the critical point. While the excitation energies in 138Gd are consistent with X(5) predictions, the large uncertainties associated with the measured B(E2) values cannot preclude vibrational and rotational contributions to the low-lying structure of 138Gd. Although experimental knowledge for the low-lying γ and β-vibrational bands in 138Gd is limited, potential-energy surface calculations suggest an increase in γ softness in the ground-state band. In order to more fully account for the effects of γ softness, the X(5) and IBM-1 calculations need to be extended to include the γ degree of freedom for 138Gd.

Articles dans des revues avec comité de lecture
Physical Review C (Phys. Rev. C)
Publisher American Physical Society
ISSN 0556-2813 (eISSN : 1089-490X)

Lifetimes – Nuclear structure models and methods – Electromagnetic transitions – 90<=A<=149