"Poincare shape transitions in hot rotating nuclei "
Katarzyna Mazurek, IFJ PAN/GANIL
(id #163)
Seminar: YesPoster: No
Invited talk: No
Poincare shape transitions in hot rotating nuclei
K. Mazurek1,2, J. Dudek3, M. Kmiecik1, A. Maj1 et al.
1 IFJ PAN Krakow, Poland
2 GANIL Caen, France
3 IPHC Strasbourg, France
The leading features of hot, fast rotating nuclei have been investigated using a realistic, the so-called Lublin-Strasbourg Drop model [1-2] that simulates the rotational nuclear behaviour using the rigid-body rotational-energy expression. The total energy has been minimized in a multidimensional space of deformation parameters and the equilibrium nuclear shapes for each given spin have been found through the total energy minimization. For low and generally not too high spins the equilibrium shape evolves from spherical to more and more oblate configurations. At high angular momenta, however, shape-transitions occur that precede rotation-induced fission. One of them, studied already for some time in the nuclear physics context is the so-called Jacobi shape transition, introduced long ago by Jacobi and known in the history of physics from the theory of rotating stellar objects [3]. The existence of the nuclear Jacobi shape transition was demonstrated experimentally through the change of the GDR strength function with increasing angular momentum [5]. But there exists yet another type of transitions (also known in astrophysics under the name of Poincare transitions [4]) that can appear in competition with the previous one [5]. While the Jacobi shape transitions preserve the left-right symmetry the transitions of the Poincare-type break this type of symmetry leading to the new type of instabilities involving the octupole- and higher order left-right asymmetric shapes.
> In this contribution we discuss the sensitivity of the method to predict such Poincare shape transitions. We report on the regions in the nuclear chart where the Poincare transitions are expected to take place. As an illustration we discuss in some details the chain of Barium isotopes. The possible observables which can experimentally verify our predictions for Poincare transitions, as for example the evolution of the GDR line shape, or mass and charge asymmetry of the fission fragments are discussed.
1.K. Pomorski, J. Dudek, Phys. Rev. C67 (2003) 044316;
2.J. Dudek, K. Pomorski, N. Schunck, N. Dubray, European Phys. J. A20 (2004) 165.
3. C.G.J. Jacobi, Vorlesungem ¨uber Dynamik, ed. A. Clebsch, printed by G. Reimer, Berlin, 1884. 3. A. Maj et al., Nucl. Phys. A731 (2004) 319.
4. H. Poincar´e, Acta Math. 7 (1885) 259.
5. A. Maj et al., Int. J. Mod. Phys. E19 (2010) 532.
K. Mazurek1,2, J. Dudek3, M. Kmiecik1, A. Maj1 et al.
1 IFJ PAN Krakow, Poland
2 GANIL Caen, France
3 IPHC Strasbourg, France
The leading features of hot, fast rotating nuclei have been investigated using a realistic, the so-called Lublin-Strasbourg Drop model [1-2] that simulates the rotational nuclear behaviour using the rigid-body rotational-energy expression. The total energy has been minimized in a multidimensional space of deformation parameters and the equilibrium nuclear shapes for each given spin have been found through the total energy minimization. For low and generally not too high spins the equilibrium shape evolves from spherical to more and more oblate configurations. At high angular momenta, however, shape-transitions occur that precede rotation-induced fission. One of them, studied already for some time in the nuclear physics context is the so-called Jacobi shape transition, introduced long ago by Jacobi and known in the history of physics from the theory of rotating stellar objects [3]. The existence of the nuclear Jacobi shape transition was demonstrated experimentally through the change of the GDR strength function with increasing angular momentum [5]. But there exists yet another type of transitions (also known in astrophysics under the name of Poincare transitions [4]) that can appear in competition with the previous one [5]. While the Jacobi shape transitions preserve the left-right symmetry the transitions of the Poincare-type break this type of symmetry leading to the new type of instabilities involving the octupole- and higher order left-right asymmetric shapes.
> In this contribution we discuss the sensitivity of the method to predict such Poincare shape transitions. We report on the regions in the nuclear chart where the Poincare transitions are expected to take place. As an illustration we discuss in some details the chain of Barium isotopes. The possible observables which can experimentally verify our predictions for Poincare transitions, as for example the evolution of the GDR line shape, or mass and charge asymmetry of the fission fragments are discussed.
1.K. Pomorski, J. Dudek, Phys. Rev. C67 (2003) 044316;
2.J. Dudek, K. Pomorski, N. Schunck, N. Dubray, European Phys. J. A20 (2004) 165.
3. C.G.J. Jacobi, Vorlesungem ¨uber Dynamik, ed. A. Clebsch, printed by G. Reimer, Berlin, 1884. 3. A. Maj et al., Nucl. Phys. A731 (2004) 319.
4. H. Poincar´e, Acta Math. 7 (1885) 259.
5. A. Maj et al., Int. J. Mod. Phys. E19 (2010) 532.
