[en] Hypernuclear gamma-ray spectroscopy experiments at J-PARC using the next generation Germanium detector array, Hyperball-J is discussed. An overview of the first experiment (E13) is summarized and the present preparation status of the magnetic spectrometer system and Hyperball-J is given. Possible gamma-ray spectroscopy studies of the sd-shell Λ hypernuclei, especially of magnesium isotopes, are presented. (author)

[en] Magnesium isotopic compositions for metal-poor and super-metal-rich stars are presented. An enhanced odd-even effect in metal-poor stars is detected

[en] Aluminium 26 is one of the extinct nuclides. It decays to ²⁶Mg with the half life of 7.2 x 10⁵ yr. In order to confirm whether ²⁶Al existed in the early solar system or not, magnesium isotopic abundance anomalies have been examined in some chondrites and terrestrial rocks by many investigators. In the present work point-to-point (SIMS) analyses of Mg isotopic anomalies were carried out for the Allende inclusions and matrix with an accuracy of about 3 parts per thousand. They were compared with that for the terrestrial forsterite sample. The results are presented and discussed. (author)

[en] Properties of strongly interacting, two-component finite Fermi systems are discussed within the recently developed coordinate-space Hartree-Fock-Bogoliubov (HFB) code HFB-AX. Two illustrative examples are presented: (i) weakly bound deformed Mg isotopes, and (ii) spin-polarized atomic condensates in a strongly deformed harmonic trap.

[en] The main objective of this work is to make a detailed study of the isospin energy and its variation with excitation energy using statistical theory in which deformation degrees of freedom and temperature effects are included

[en] We theoretically investigate the temporal dynamics of nuclear spin induced by short laser pulses. To realize ultrafast nuclear spin polarization, we coherently excite the hyperfine manifolds and let it evolve in time. An appropriate choice of the state with large hyperfine splittings allows us to realize ultrafast nuclear spin polarization. As specific examples, we consider the various isotopes of Mg and Ca with different values of nuclear spin (1/2, 3/2, 5/2, and 7/2) and show that 89%, 76%, 49%, and 36% of nuclear spin polarization can be achieved, respectively, within a few nanoseconds, which is at least 2 to 3 orders of magnitude shorter than the time needed for any known optical methods. Because of its ultrafast nature, our scheme would be very effective not only for stable nuclei but also unstable nuclei with a lifetime as short as 1 μs

[en] After the successful commissioning of the Radioactive beam EXperiment (REX) at ISOLDE (CERN) in 2002, first physics experiments were performed in 2003 which focussed on the neutron-rich Mg isotopes in the vicinity of the 'island of inversion'. After introducing the REX facility and the modern γ spectrometer MINIBALL first preliminary results will be presented showing the high potential and physics opportunities offered by this new radioactive beam facility

[en] The ground state properties of Mg isotopes are systematically investigated by the macroscopic-microscopic (MM) model with an isospin-dependent spin-orbit potential. Special emphasis is placed on the deformation and the disappearance of the N=20 magic number. The calculated results provide a good description of the binding energies and the deformations. The calculation reproduces the large deformations for nuclei around N=20. The exotic properties around N=20 are discussed, and their origin can be explained by the isospin-dependent spin-orbit force. Shell correction plays an important role for the appearance of large deformations of Mg isotopes. Experimental B(E2) values are approximately reproduced and the possible appearance of shape coexistence is discussed

[en] A new single-particle basis is proposed for use in weakly-bound nuclei far from the valley of beta stability. The basis, obtained by applying a local-scaling point transformation to the states of a harmonic oscillator potential can have the correct asymptotic properties for weakly-bound systems. It is presented a test of the basis and then applied it in Hartree-Fock-Bogoliubov calculations of the even Mg isotopes, from the proton drip line to the neutron drip line

[en] A plausible scenario is advanced for explainig a linear correlation found in some solar system solids between their Mg-26/Mg-24 isotopic ratios and their Al/Mg elemental abundance ratios. This scenario involves three stages: (1) the mechanical aggregation of an average ensemble of Al-bearing dust particles that is postulated to be modestly enriched in the Al/Mg abundance ratio because the aggregated particles themselves are; (2) the extraction, perhaps but not necessarily by hot distillation, of almost all Mg, leaving an aggregate with a large Al/Mg ratio and a large Mg-26 excess; and (3) the uptake of normal ambient Mg by the resulting hot Al-rich solid as it cools in Mg-rich vapor. A linear correlation in solids between their Mg-26/Mg-24 isotopic ratio and their aluminum enrichment may be a fossil correlation inherited from interstellar dust. 36 references