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It has recently been suggested that differences in the charge radii of mirror nuclei (Δ R ch mirr) are strongly correlated with the neutron-skin thickness (R skin) of neutron-rich nuclei and with the slope of the symmetry energy (L). To test this assumption, we present ab initio calculations of R skin in 48Ca and 208Pb, Δ R ch mirr in 36Ca − 36 S, 38Ca − 38 Ar, 41Sc − 41 Ca, 48Ni − 48 Ca, 52Ni − 52 Cr, and 54Ni − 54 Fe mirror pairs, and L. Employing the recently developed 34 chiral interaction samples, identified by the history matching approach, we conduct rigorous statistical analysis of correlations among Δ R ch mirr , R skin and L , accounting for quantified uncertainties from low-energy constants of chiral interaction, chiral effective field theory truncation and many-body method approximation. The ab initio results reveal an appreciable Δ R ch mirr − L correlation in fp -shell mirror pairs. However, contrary to previous studies, the present calculation finds that the studied sd -shell mirror pairs do not exhibit any Δ R ch mirr − L correlation. [ABSTRACT FROM AUTHOR]

Abstract A thick neutron skin emerges from the first determination of root mean square radii of the proton distributions for 17−22N from charge changing cross section measurements around 900 A MeV at GSI. Neutron halo effects are signalled for 22N from an increase in the proton and matter radii. The radii suggest an unconventional shell gap at N = 14 arising from the attractive proton–neutron tensor interaction, in good agreement with shell model calculations. Ab initio , in-medium similarity re-normalization group, calculations with a state-of-the-art chiral nucleon–nucleon and three-nucleon interaction reproduce well the data approaching the neutron drip-line isotopes but are challenged in explaining the complete isotopic trend of the radii. [ABSTRACT FROM AUTHOR]

The cross sections of the isovector spin-dipole resonances (SDR) in the Sb isotopes have been measured. Within the model used, the neutron-skin thicknesses r skin (exp) deduced 0. 12 ± 0. 06 fm for 116Sn, 0. 13 ± 0. 06 fm for 118Sn, 0. 18 ± 0. 07 fm for 120Sn, 0. 22 ± 0. 07 fm for 122Sn, 0. 19 ± 0. 07 fm for 124Sn. We tested the chiral (Kyushu) g -matrix folding model for 12C+12C scattering, and found that the Kyushu g -matrix folding model is reliable for reaction cross sections σ R in 30 ˜ < E in ˜ < 100 MeV and 250 ˜ < E in ˜ < 400 MeV. We determine neutron skin thickness r skin (exp) , using measured σ R of 4He+116,120,224Sn scattering. The results are r skin (exp) = 0. 242 ± 0. 140 fm for 116Sn, r skin (exp) = 0. 377 ± 0. 140 fm for 120Sn, r skin (exp) = 0. 180 ± 0. 142 fm for 124Sn. The σ R are available for proton scattering on 116,118,120,122,124Sn with high accuracy of 2 ∼ 3 % as a function of incident energy E in. Our aim is to determine r skin (exp) for 116,118,120,122,124Sn with small errors by using the Kyushu g -matrix folding model. Our model is the Kyushu g -matrix folding model with the densities scaled from the D1S-GHFB+AMP neutron density, where D1S-GHFB+AMP stands for Gogny-D1S HFB (D1S-GHFB) with the angular momentum projection (AMP). The proton radii of D1S-GHFB+AMP agree with those calculated with the isotope shift method based on the electron scattering. We then scale the D1S-GHFB+AMP neutron densities so as to reproduce the σ R (exp). In 30 ˜ < E in ˜ < 65 MeV , we determine r skin (exp) from measured σ R. The values are r skin (exp) = 0. 118 ± 0. 021 fm for 116Sn, 0. 112 ± 0. 021 fm for 118Sn, 0. 124 ± 0. 021 fm for 120Sn, 0. 156 ± 0. 022 fm for 124Sn. As for 122Sn, the skin value in 30 ˜ < E in ˜ < 50 MeV is 0. 122 ± 0. 024 fm. Our results are consistent with the previous values. [ABSTRACT FROM AUTHOR]

Abstract: The electric dipole response of atomic nuclei has attracted a lot of attention from experimentalists and theorists in the last decade. This review gives an overview about the present status of experimental approaches to study low-lying electric dipole strength (often denoted as Pygmy Dipole Resonance) in stable and radioactive atomic nuclei and discusses the implications of these findings. Data published until July 2012 have been taken into account. [Copyright &y& Elsevier]

Abstract: A search of the pygmy resonance in 68Ni was made using the virtual photon technique. The experiment was carried out using the radioactive beam 68Ni at 600 A MeV, produced with fragmentation of 86Kr at 900 A MeV on a 9Be target. The 68Ni beam was separated by a fragment separator, and the -rays produced at the interaction with the Au target were detected with the RISING and FRS set-up at the GSI laboratory in Germany, also including the HECTOR array. The measured -ray spectra show a peak centered at approximately 11 MeV, whose intensity can be explained in term of an enhanced strength of the dipole response function (pygmy resonance). A pygmy structure of this type was also predicted by different models for this unstable neutron-rich nucleus. Correlations between the behavior of the nuclear symmetry energy, the neutron skins, and the percentage of energy-weighted sum rule (EWSR) exhausted by the pygmy dipole resonance (PDR) are investigated by using different random phase approximation (RPA) models. [Copyright &y& Elsevier]

Abstract: The states of 8He are studied in a five-body cluster model. Many-body resonances are treated on the correct boundary condition as Gamow states using the complex scaling method. The state of 8He is predicted as a five-body resonance in the excitation energy of 6.3 MeV with a width of 3.2 MeV, which mainly has a configuration. In this state, number of the neuron pair shows almost two, which is different from the ground state having a large amount of the pair component. The monopole transition of 8He from the ground state into the five-body unbound states is also evaluated. It is found that the component mostly exhausts the strength, while the contribution is negligible. The final states are dominated by , not . The results indicate the sequential breakup process of by the monopole excitation. [Copyright &y& Elsevier]

Abstract: The dependence between neutron-to-proton yield ratio () and neutron skin thickness () in neutron-rich projectile induced reactions is investigated within the framework of the Isospin-Dependent Quantum Molecular Dynamics (IQMD) model. The density distribution of the Droplet model is embedded in the initialization of the neutron and proton densities in the present IQMD model. By adjusting the diffuseness parameter of neutron density in the Droplet model for the projectile, the relationship between the neutron skin thickness and the corresponding in the collisions is obtained. The results show strong linear correlation between and for neutron-rich Ca and Ni isotopes. It is suggested that may be used as an experimental observable to extract for neutron-rich nuclei, which is very significant to the study of the nuclear structure of exotic nuclei and the equation of state (EOS) of asymmetric nuclear matter. [Copyright &y& Elsevier]

Abstract: The collective multipole response of neutron-proton asymmetric nuclei has been investigated experimentally so far mainly utilizing the heavy-ion induced electromagnetic excitation. The experimental findings concerning the dipole strength in neutron-rich nuclei are summarized and a brief outlook is given. [Copyright &y& Elsevier]

Abstract: Some aspects, both experimental and theoretical, of extracting the neutron skin from properties of isovector giant resonances are discussed. Existing proposals are critically reviewed. The method relying on the energy difference between the Gamow–Teller resonance and the isobaric analogue state is shown to lack sensitivity to . A simple explanation of the linear relation between the symmetry energy and the neutron skin is also presented. [Copyright &y& Elsevier]

Abstract: Binding energy of isospin asymmetric nuclei can be accessed with minimally modified formula along the lines of the liquid droplet model by partitioning the symmetry term into volume and surface terms. The volume symmetry energy coefficient extracted from finite nuclei provides a constraint on the nuclear symmetry energy. This approach also yields the neutron skin of a finite nucleus through its relationship with the volume and surface symmetry terms and the Coulomb energy coefficient. The symmetry energy at saturation density obtained from the isoscalar as well as isovector components of the density dependent M3Y effective interaction is found to be in close agreement with the volume symmetry energy coefficient extracted from the measured atomic masses. [Copyright &y& Elsevier]

Selected topics in present days nuclear structure physics studied by reactions of RI beams are presented. They are change in nuclear radii, single particle orbitals, and shapes. Dynamical changes are shown for nuclei far from the stability line in particular in p-sd shell. Among the future reaction study, a thick target method for a storage ring is presented. A possibility to obtain the highest luminosity for an internal target experiment is proposed. [Copyright &y& Elsevier]