Proton inelastic scattering from ¹¹Li

A review of evidence on the properties of the $A=11$ nuclei, with emphasis on material leading to information about the structure of the $A=11$ systems.

FaCE is a self contained program, with namelist input, that solves the three body Faddeev equations. It enables the inclusion of excitation of one of the three bodies, whilst the other two remain inert. It is particularly useful for obtaining the binding energies and bound state structure compositions of light exotic nuclei treated as three-body systems, given the three effective two body interactions. A large variety of forms for these interactions may be defined, and supersymmetric transformations of these potentials may be calculated whenever two body states need to be removed due to Pauli blocking.

Title of program: FaCE (Faddeev with Core Excitation)

Catalogue identifier: ADTW

Program summary URL: http://cpc.cs.qub.ac.uk/summaries/ADTW

Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland

Computers: The code is designed to run on any Unix/Linux workstation or PC.

Operating systems: Linux or UNIX

Program language used: Fortran-90

Numerical libraries used: Source code for 6 routines from the NAG and BLAS libraries is included to enable independent compilation.

Memory required to execute with typical data: 9 Mbytes of RAM memory and 12 MB of hard disk space.

No. of bits in a word: 32 or 64

No. of bytes in distributed program, including test data, etc.: 116 514

No. of lines in distributed program, including test data, etc.: 15 574

Distribution format: tar gzip file

Nature of physical problem: The program calculates eigenenergies and eigenstates for the three body problem by solving the Faddeev equations.

Method of solution: Given the two body effective potentials it performs the supersymmetric transformation in case where there are forbidden states to be removed. The three body wavefunction is expanded in hyperspherical coordinates, the hyper-angular part is a series of Jacobi polynomials and the hyper-radial part is written in terms of a Laguerre basis. Within this basis the three body matrix elements are calculated and the full three body Hamiltonian matrix is completed. The diagonalization process is performed after various reductions (isospin, orthonormal and Feshbach) to determine the energies. Finally the three body wavefunction is reconstructed and other bound state observables are calculated.

Typical running time: 6 s on a 1.7 GHz Intel P4-processor machine.

Halo nuclei are characterized by outer nucleons that reside mostly in the classically forbidden region. The large average distance of halo nucleons suggests the decoupling of core and halo degrees of freedom. This is the basis for the few-body structure models developed in the past decade. Few-body models have been the most frequent tool when probing the halo structure. Coulomb dissociation, Knock-out or Transfer reactions have provided detailed structure information for exotic nuclei. Nowadays, the accumulating data impose severe tests for the few-body models. We discuss the achievements of these models as well as their limitations. To cite this article: F.M. Nunes, C. R. Physique 4 (2003).

Les noyaux à halo sont caractérisés par des nucléons externes qui résident la plupart du temps dans la région classiquement interdite du potentiel nucléaire. La grande distance moyenne des nucléons du halo suggère le découplage des degrés de liberté du coeur et du halo. Cela sert de base aux modèles de structure à petit nombre de corps développés durant la décennie passée. Les modèles à petit nombre de corps ont été l'outil le plus fréquemment employé pour déterminer la structure des noyaux à halo. La dissociation coulombienne, les réactions d'éjection (knock-out) ou de transfert ont fourni des informations structurelles détaillées pour ces noyaux exotiques. Aujourd'hui, l'ensemble des données accumulées, permet des tests rigoureux des modèles de noyaux à halo. Nous discutons les succès de ces modèles aussi bien que leurs limitations. Pour citer cet article : F.M. Nunes, C. R. Physique 4 (2003).

The changes in nuclear structure far from the stability line are reviewed for light nuclei. The basic concepts of neutron and proton skins and neutron halos are presented with several experimental data. Signatures of new mode of collective excitation as consequences of such exotic structures are also shown. These changes of structure point to the need for the detailed study of single-particle orbitals for unstable nuclei. Such recent studies, in particular, the spectroscopic information of halo states, are reviewed. Changes of neutron orbital ordering away from the stability line are observed from such studies. Its most profound implication has emerged in the change of magic numbers. An over view of magic number variation is presented. To cite this article: I. Tanihata, R. Kanungo, C. R. Physique 4 (2003).

Les modifications de la structure nucléaire loin de la stabilité sont passées en revue. Les concepts de Halos et de peaux de protons et de neutrons sont présentés en s'appuyant sur de nombreux résultats expérimentaux. Des signatures des nouveaux modes collectifs attendus comme conséquences de ces structures exotiques sont aussi décrites. Ces profondes transformations de la structure des noyaux démontrent la nécessité d'étudier les orbitales des nucléons dans les noyaux instables. Ces études récentes, en particulier en ce qui concerne les informations spectroscopiques pour les noyaux à halos, sont résumées. Une modification de l'ordre des orbitales de neutrons loin de la stabilité a été observée lors de ces études. L'implication la plus spectaculaire de cette transformation est la modification des nombres magiques. Une synthèse des résultats sur la modification de la magicité est finalement présentée. Pour citer cet article : I. Tanihata, R. Kanungo, C. R. Physique 4 (2003).