Vers une approche microscopique unifiée de la description de les structures et des réactions nucléaires

Abstract : This thesis contains 3 main parts: 1. Nuclear matter: The properties of nuclear matter are examined using finite range effective interactions, either derived from the Brueckner theory (M3Y-type interactions) or determined in a purely phenomenological way (Gogny-type interactions). Skyrme-type interactions are also used for comparison. The motivation of the study is to establish a link be- tween the bare NN interaction and nuclear matter properties via the e®ective Brueckner G-matrix parameterized in the M3Y form. We have concentrated our discussion on several main aspects: the pressure in symmetric nuclear matter and in neutron matter, the density dependence of the symmetry energy S, the neutron star cooling, and the nuclear matter incompressibility for the symmetric and asymmetric nuclear matter. 2. Structure of finite nuclei and of the inner crust of neutron stars: We present the non-relativistic HF and HF-BCS approaches in coordinate representation using finite-range density-dependent interactions in both the mean field and pairing channels. The method for solving the HF equations in coordinate space is presented. We limit the study to the spherical symmetry case. An iterative scheme is used for solving the integro-differential HF equations. We adopt the method of Brueckner-Gammel-Weizner which is free of poles in the local equivalent potentials, in contrast to the usually used Vautherin-Vénéroni method. Alternatively, we have developed a method using a basis of spherical Bessel functions. The latter method is useful for treating systems containing many nucleons in large boxes like the Wigner-Seitz (WS) cells of the neutron star inner crust. We have thus studied, using the e®ective interactions mentioned above, the doubly magic nuclei, the Sn isotopes, and the possible occurrence of bubble structures in the nuclei 22O, 34Si, 46Ar and 68Ar. We also present for the ¯rst time a study of Wigner-Seitz cells in the inner crust of neutron stars using ¯nite range interactions. We have thus examined the structures of the di®erent zones of the inner crust, from the lowest densities up to densities close to the vicinity of half saturation density where the spherical assumption breaks down. 3. Nuclear reactions: Using the same effective interactions derived from the M3Y-type interactions we have performed a coupled channel analysis of (p,n) charge exchange reactions at 35 and 45 MeV incident energies on 48Ca, 90Zr, 120Sn and 208Pb targets leading to isobaric analog states. The form factors are either calculated microscopically by the convolution model, or evaluated from the global optical potential taken from the literature. We have first determined the component of the CDM3Y6 interaction which depends on the isovector density by using the microscopic optical potential of Jeukenne, Lejeune and Mahaux, and then this was used for the folding model. Thus, we have been able to assess the validity of the component of CDM3Y6 which depends on the isovector density.
Document type :
Theses
Nuclear Theory [nucl-th]. Université Paris Sud - Paris XI, 2009. French


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S. T. Hoang. Vers une approche microscopique unifiée de la description de les structures et des réactions nucléaires. Nuclear Theory [nucl-th]. Université Paris Sud - Paris XI, 2009. French. <tel-00488850>

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