Chiral and magnetic rotation in atomic nuclei studied within self-consistent mean-field methods
Résumé
Currently, one application of the mean-field methods in nuclear physics is the investigation of exotic nuclear symmetries. This is related, in particular, to the study of nuclear rotation about an axis tilted with respect to the principal axes of the mass distribution in the Tilted-Axis Cranking (TAC) model. The present work presents one of the first TAC calculations performed within fully self-consistent methods. The Hartree-Fock method with the Skyrme effective two-body interaction has been used. A computer code has been developed that allows for the breaking of all spatial symmetries of the solution. As a first application, calculations for the magnetic bands in 142Gd and for the chiral bands in 130Cs, 132La, 134Pr, and 136Pm have been carried out. The appearance of those bands is due to a new mechanism of breaking the spherical symmetry and to the spontaneous breaking of the chiral symmetry, respectively. The self-consistent solutions for 142Gd confirm the important role of the shears mechanism in generating the total angular momentum. However, the agreement with experimental data is not satisfactory, probably due to the lack of the pairing correlations in the calculations or to the possibly overestimated deformation. The results obtained for 132La constitute the first fully self-consistent proof that the nuclear rotation can attain a chiral character. It has been shown that the chiral rotation can only exist above a certain critical angular frequency. It has also been checked that the terms of the Skyrme mean field odd under the time reversal have no qualitative influence on the results.
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