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Accueil du site > FRANCAIS > Communication > Séminaires > Année 2010 > New shape effects in hot rotating nuclei : Jacobi vs. Poincare shape transitions


New shape effects in hot rotating nuclei : Jacobi vs. Poincare shape transitions

Kasia Masurek, GANIL Caen
Mardi 1 Juin 2010 à 10h30 - Salle des Séminaires

The shape evolution of hot rotating nuclei gives us an opportunity to investigate structural phenomena such as Giant Dipole Resonances or asymmetric fission. In particular the Jacobi shape transitions, known in the history of Physics from the theory of rotating stellar objects, can be demonstrated experimentally through the change of the GDR strength function with increasing angular momentum. Yet, there exists another type of transitions (also known in Astrophysics under the name of Poincare transitions) that can appear in competition with the previous one. More precisely, while the Jacobi shape transitions preserve the left-right symmetry, the transitions of the Poincare type break this type of symmetry leading to instabilities involving the octupole-type shapes. In Nuclear Physics such phenomena can serve to better understand, e.g., the asymmetric fission. Illustrations are presented using the results of calculations with the so-called Lublin-Strasbourg Drop (LSD) model, which is believed to provide a good approximation of the behaviour of hot, fast rotating nuclei.