九大原子核セミナー

2018年3月1日(木) 16:30〜18:00

講師：Jirina Stone 氏(Tennessee大学)

演題：Superheavy nuclei in the Quark-Meson Coupling model

場所：ウェスト1号館7階 物理会議室 (W1-A-723室)

概要：
The fundamental problem of low energy nuclear structure is the understanding the change of the free nucleon-nucleon force in the nuclear medium. Commonly used forces of the Skyrme or Gogny type, with their empirical medium density dependence, cannot be determined uniquely. Hundreds of such forces have been constructed, fitting their numerous correlated parameters to selected experimental data. We report a single, four-parameter form of the density dependent effective nucleon-nucleon force based on modification of the nucleon structure in-medium on the quark level, which represents a new paradigm for nuclear physics. The model yields results for the ground-state binding energies, electromagnetic properties and shapes of even-even nuclei, from the lightest to superheavy, in agreement with experiment within less than a few percent [1].
I will discuss the latest results obtained for binding energies, deformations and single-particle energies of even-even nuclei in the region of 100 < Z < 110 and their comparison with available experimental data. Extension of the model to nuclei with the atomic number up to 120, predicted shell closures and attempts to identify an island of stability in the superheavy region will be reported [2].

[1] J.R.Stone, P.A.M. Guichon, P.-G. Reinhard and A.W. Thomas,
Phys.Rev.Lett. 116, 092501 (2016)
[2] J.R.Stone, P.A.M.Guichon and A.W.Thomas, https://arxiv.org/abs/1706.01153v1

2018年2月6日(火) 16:30〜18:00

講師：佐川弘幸 氏(会津大学/理研)

演題：IS and IV pairing correlations and Spin-Isospin Response

場所：ウェスト1号館7階 物理会議室 (W1-A-723室)

概要：
Pairing correlations are one of the most important effects in nuclear structure and reactions.Spin-singlet isovector pairing correlations have been discussed from late 1950s and the spin-singlet superfluidity is well established in several observations such as the energy spectra of even-even nuclei and the moment of inertia of deformed nuclei. It is also known that the spin-triplet isoscalar pairing interaction is much stronger than the isovector one in the nuclear matter calculations. The existence of deuteron certainly proves the strong spin-triplet isoscalar correlations. I will discuss in this talk how we can nd out the effect of isoscalar pairing correlations in spin-isospin response of N=Z nuclei, especially magnetic dipole transitions and Gamow-Teller transitions.