NUCLEAR STRUCTURE

Author: IGLESIA MEDINA FERNANDO DE LA.
Year: 2003.
University: AUTÓNOMA DE MADRID [www.uam.es].
Place of defense: DEPARTAMENTO DE FÍSICA TEÓRICA C-XI DE LA FALCULTAD DE CIENCIAS.
Place of preparation: UNIVERSIDAD AUTÓNOMA DE MADRID.

Summary: The models field half tools have proven very eficacespara understand the behavior of the dynamics of the atomic nucleus from a microscopic point of view. Of all of them, perhaps the most important is elmétodo of Hartree-Fock-Bogoliubov because thanks to the flexibility it provides latransformación of cuasiparticula that is used on him, has the ability dedescribir to consistently field autoconsistente of Hartree - Fock and the deapareamiénto simultaneously. The theory Hartree-Fock-Bogoliubov (HFB) hasido applied with great success in the study of many properties using nuclear interactions phenomenological effective as fuerzade Gogny or the Skyrme and along with restoration techniques simetríasde accurately or in combination with the method of generating coordinate. Usually, the practical treatment for solving the equation of HFB is habasado in developing operators cuasiparticula bases functions such as orthogonal wave oscillator armónicotridimensional. to overcome this problem, this thesis we considered the use debases functions wave type gausiana with lengths característicasdistintas in solving the equation of HFB. This way, we want to have flexibility simultaneously at the base so that it can adapt alos try and ease problems in the calculation of matrix elements dela interaction appearing in the equations using HFB as interacciónefectiva phenomenological force Gogny. Given that foundation as the proposals are clearly not orthogonal, in this tesisse has extended formalism HFB so that it can accommodate the use of bases departícula not orthogonal. It has also carried out the assessment analíticade lós elements matrix necessary for the interaction of Gogny and basesgausianas used. All this formalismose has finally implemented in a computer program that has allowed us to explore different types of particle bases in variosejemplos significant on neutron-rich nuclei much as decarbono 22. They are considering two different types of foundation: In the first type (type 1) the funcionesde wave basis are the product of a factor gausíano Sometimes a monomial. Laslongitudes characteristics factor gausiano depend on the degree of monomiousado. In the second type (type 11), the wave functions of the product are based on unmonomio sometimes a linear combination of factors gausianos with longitudescaracterísticas prefixed but allowing coefficients lacombinación linear dependence of the state in question. The results show that both the groundwork for Type I and Type 11 are those of a good alternative for describing the asymptotic behavior of the orbital nuclear and / or systems rich in neutrons conorbitales occupied near the Fermi level and widespread spatially. In particular, the groundwork for Type 11ha shown reproduce with great fidelidadel behavior of the asymptotic nuclear orbital and therefore seems seruna candidate optimal for the study of systems neutron dondedicho behavior rich is crucial.

Author: Caballero Ontanaya Luis.
Year: 2005.
University: VALENCIA [www.uv.es].
Place of defense: Facultad de Física, Universitat de València.
Place of preparation: Facultad de Física, Universitat de València.

Summary: In the present work we studied the multiplets of partícula-hueco and states two fonones at the heart of 146Gd. The core of 146Gd is located within the periodic table in the region of the rare earth and belongs to the group of lantánidos. This kernel provides a `` gap''of about 2.4 MeV energy in Z = 64, jointly known to the magical nature of N = 82, gives the 146Gd many of the features of the doubly magic nucleus. The 146Gd is the only core alongside the 208Pb introducing a state 3-as the first excited state and, unlike the 208Pb is accessible reactions in `` beam''. The study of multiplets of 146Gd has a particular interest because it provides information about the interaction residual nucleón-nucleón and fundamental data for the calculations of layered model of the region. These statements double octupolo in doubly magic nucleus has been predicted for a long time and have been experimentally searched intensively in the 208Pb. Some candidates have been solid recently proposed [1]. Also in the nuclei neighboring 146Gd have been identified such statements (see [2.3] to the states 147Gd (vf7/2Ã3-Ã3-) and 148Gd (v ² Ã3-Ã3-)). At work in `` beam''Yates et al. [3] suggested two possible candidates for these states. The confirmation of these statements in 146Gd and identifying the remaining members of multiplet (3-Ã3-) is one of the main objectives of this work. This paper has studied the reaction of fusión-evaporación 144Sm (a, 2n) using a beam of particles' a 'to an energy of 26.3 MeV effect above a target of 144Sm was 3.0 mg / cm ² thickness enriched to 97.6% on a base of 0.5 mg / cm ² Au. The sensitivity of our experiment was about 10 times better than the previous one made by Yates et al. [3]. For the detection of gamma employ 10 detectors located germanium to 90, +-45 and + -35 degrees. One of the detectors was a detector CLUSTER capsules composed of seven independent germanium, to be located at 90 degrees, he functions polarimeter. Given the disposition of detectors, it has also been possible extraction of an angular anisotropy. The combination of information extracted from the anisotropy and polarization enables the identification of multipolarity and nature (electric or magnetic) of the transition. As a result of this analysis have found a total of 56 new bridges gamma for 44 new states and 50 new gamma rays coming from 39 states previously known. Likewise, there have been 10 transitions previously unseen in experiments in `` beam''. In general the states have been confirmed previously known. Thanks to the great progress made in the knowledge of excited states in this nucleus, it has been possible to identify new candidates or members of multiplets of two particles, as well as for members of multiplets two fonones. These include the identification of the state 6 + twice octupolo as well as observing first of a cascade of two transitions E3 (6 +-> 3--> 0 +). [1] Minfang Yeh, M. Kadi, PE Garrett, CA McGrath, SW Yates and T. Belgya: Phys. REV. C 57, 5 (1998) [2] Kleinheinz, P., Stryczen, J., Piiparinen, M., Blomqvist, J., Kortelahti, M.: Phys. REV. Lett. 48, 1457 (1982) [3] Lunardi, S., Kleinheinz, P., Piiparinen, M., Ogawa, M., Lach, M., Blomqvist, J. Phys. REV. Lett. 53, 1531 (1984) [4] Yates, SW, Julin, R., Kleinheinz, P. Rubio, B. Mann, LG, Henry, EA, St. "offl, W., Decman, DJ, Blomqvist, J .: Z. Phys. Atoms A - and Nuclei 324, 417 (1986)

Author: RODRÍGUEZ VIGNOTE JAVIER.
Year: 2005.
University: COMPLUTENSE DE MADRID [www.ucm.es].
Place of defense: FACULTAD DE CIENCIAS FÍSICAS.
Place of preparation: FACULTAD DE CIENCIAS FÍSICAS.

Summary: In this thesis is reviewed approximate relativistic momentum to the process (e, e ', p), and compared with available experimental data and confrontation by the non-relativistic analysis. The first chapter introduces the process (e, e ', p), is reviewed briefly formalism and summarizes the derivation dela cross section that appears in a more comprehensive fashion in an appendix. In Chapter 2 examines in detail the approximation factorizada the process (e, e ', p) in the distorted wave approximation for the proton. In chapter 3 applies formalism relativistic wave distorted the analysis of experimental data of sections effective and observable ATL in 16O. In chapter 4 is a study of data from the cyclotron MAMI of Mainz for the reaction 4He (e, e ', p) 3 has transferred moments moderate. In chapters from 5 to 8 introduces the degrees of freedom of polarization of the outgoing nucleon in the analysis. Issues related to the induced polarization in chapter 5 and polarizations transferred in chapter 6. In chapters 7 and 8 discusses experiments measuring polarization normal polarization ratios and transferred them in 4He. Finally, in Chapter 9 presents a discussion of unifying all the previous chapters and chapter 10 shows the conclusions of the work done.

Author: ÁLVAREZ RODRÍGUEZ RAQUEL.
Year: 2005.
University: COMPLUTENSE DE MADRID [www.ucm.es].
Place of defense: FACULTAD DE CIENCIAS FÍSICAS.
Place of preparation: FACULTAD DE CIENCIAS FÍSICAS UCM.

Summary: We studied some of the most interesting nuclear processes governed by the weak interaction: on the one hand process of astrophysical interest, as distributions of intensity Gamow-Teller and processes of rapid proton capture, which will help us better understand the stellar nucleosynthesis and the nuclear abundances But on the other hand the double beta decay, one of the rarest process in Nature with important implications for the study of neutrinos and validation of the Standard Model. We started by conducting a description of the theoretical formalism, from the most basic concepts related to the weak interaction, until formalism of pnQRPA based on fear of a field with deformed Hartree - Fock interactions nucleón-nucleón type Skyrem and correlations mating according to the theory BCS. We studied below the Fermi transitions, we used to study the mixture isoespín of wave functions that we are using. One sees that these transitions are only important when studying beta decay near the line N = Z. We calculate the distributions of intensity Gamow-Teller in various isotopes in the region of 56Fe and compared with the experimental data obtained from charge exchange reactions; good agreement with these data gives us confidence to apply this same approach to other Process weak. We study the half-lives of various nuclei waiting point of astrophysical interest in the region averages around mass N = Z recital, the effect of deformation in these half-lives and compared with experimental values. We conducted a survey of double beta decay with two neutrino emission using the same formalism, we describe this process as two transitions Gamow-Teller successive through stadiums 1 + core intermediate. Consider the ten nuclei for which the half-life of this process has been far, what we study the effects of deformation of the nuclei father and son and the residual interactions in the matrix element of this process. We put an end to this chapter with a summary and conclusions.