北海道大学 · 物理学・天文学
W. Horiuchi教授の研究室は、ハートリー=フォック法やグレイバー・モデルを用いた多体系量子系の高精度な理論的解析を柱としています。特に、中性子ハローやドリップライン核の構造・反応性を、実験データと一致するように精密に記述する研究が進んでいます。核子間の強い相互作用や相関効果を考慮した波動関数の構築、ならびに反応断面積の理論的予測が、新規核種の性質解明に貢献しています。
Figures are computed from collected data and may differ slightly.
We systematically analyze total reaction cross sections of carbon isotopes with $N=$ 6--16 on a $^{12}\mathrm{C}$ target for wide range of incident energy. The intrinsic structure of the carbon isotope is described by a Slater determinant generated from a phenomenological mean-field potential, which reasonably well reproduces the ground-state properties for most of the even $N$ isotopes. We need separate studies not only for odd nuclei but also for $^{16}\mathrm{C}$ and $^{22}\mathrm{C}$ to impr
A dripline nucleus $^{22}\mathrm{C}$ is studied in a Borromean three-body model of $^{20}\mathrm{C}+n+n$. The valence neutrons, interacting via a realistic potential, are constrained to be orthogonal to the occupied orbits in $^{20}\mathrm{C}$. We obtain ample results supporting that $^{22}\mathrm{C}$ is an ideal $s$-wave two-neutron halo nucleus: The ground state is bound by 390--570 keV, the root mean square neutron and proton radii are 4.0 and 2.4 fm, and the two neutrons are predominantly in
A candidate of a neutron-halo nucleus, $^{31}\mathrm{Ne}$, contains a single neutron in the $\mathit{pf}$ shell. Within the Glauber and eikonal models, we analyze reactions used to study $^{31}\mathrm{Ne}$. We show in a $^{30}\mathrm{Ne}+n$ model that the magnitudes of the total reaction and above all of the one-neutron removal cross sections of $^{31}\mathrm{Ne}$ on $^{12}\mathrm{C}$ and $^{208}\mathrm{Pb}$ targets strongly depend on the orbital angular momentum of the neutron, thereby providin
A systematic analysis is made on the total reaction cross sections for Ne, Mg, Si, and S isotopes. The high-energy nucleus-nucleus collision is described based on the Glauber model. Using the Skyrme-Hartree-Fock method in the three-dimensional grid-space representation, we determine the nuclear density distribution for a wide range of nuclei self-consistently without assuming any spatial symmetry. The calculated total reaction cross sections consistently agree with the recent cross section data
Excited states of $^{4}\mathrm{He}$ are studied in four-body calculations with explicitly correlated Gaussian bases. All the levels below ${E}_{x}=26$ MeV are reproduced reasonably well using realistic potentials. An analysis is made to show how the ${0}_{2}^{+}$ state becomes a resonance but those having almost the same structure as this state in different spin-isospin channels are not observed as resonances. The role of tensor force is stressed with a particular attention to the level spacing
There are some discrepancies in the low-energy data on the photoabsorption cross section of ${}^{4}$He. We calculate the cross section with realistic nuclear forces and explicitly correlated Gaussian functions. Final-state interactions and two- and three-body decay channels are taken into account. The cross section is evaluated using two methods: With the complex scaling method the total absorption cross section is obtained up to the rest energy of a pion, and with the microscopic $R$-matrix met
The momentum distribution of relative motion between two nucleons gives information on the correlation in nuclei. The momentum distribution is calculated for both $^{6}\mathrm{He}$ and $^{6}\mathrm{Li}$, which are described in a three-body model of $\ensuremath{\alpha}+N+N$. The ground-state solution for the three-body Hamiltonian is obtained accurately using correlated basis functions. The momentum distribution depends on the potential model for the $N\text{\ensuremath{-}}N$ interaction. With u
Background: Proton and neutron radii are fundamental quantities of atomic nuclei. To study the sizes of short-lived unstable nuclei, there is a need for an alternative to electron scattering.Purpose: The recent paper by Horiuchi et al. [Phys. Rev. C 89, 011601(R) (2014)] proposed a possible way of extracting the matter and neutron-skin thickness of light- to medium-mass nuclei using total reaction cross section, ${\ensuremath{\sigma}}_{R}$. The analysis is extended to medium to heavy nuclei up t
We analyze total reaction cross sections, ${\ensuremath{\sigma}}_{R}$, to explore their sensitivity to the neutron-skin thickness of nuclei. We cover 91 nuclei of O, Ne, Mg, Si, S, Ca, and Ni isotopes. The cross sections are calculated in the Glauber theory using the density distributions obtained with the Skyrme-Hartree-Fock method in three-dimensional coordinate space. Defining a reaction radius, ${a}_{R}=\sqrt{{\ensuremath{\sigma}}_{R}/\ensuremath{\pi}}$, to characterize the nuclear size and
A five-body calculation of ${}^{12}$C$\phantom{\rule{0.16em}{0ex}}+\phantom{\rule{0.16em}{0ex}}n+n+p+p$ is performed to take a step towards solving an outstanding problem in nuclear theory: the simultaneous and accurate description of the ground and first excited 0${}^{+}$ states of ${}^{16}$O. The interactions between the constituent particles are chosen consistently with the energies of bound subsystems, especially ${}^{12}$C$\phantom{\rule{0.16em}{0ex}}+\phantom{\rule{0.16em}{0ex}}n$, ${}^{12
A three-body model of $^{14}\mathrm{C}$ $+n+n$ is applied to study the energy spectrum and the hindered E2 transition in $^{16}\mathrm{C}$. A realistic two-nucleon potential is used for the valence neutrons. Both spin-singlet and spin-triplet components for the neutrons are taken into account. The three-body problem with a Pauli constraint is solved in a stochastic variational method. For the $n\text{\ensuremath{-}}$$^{14}\mathrm{C}$ potential chosen to reproduce the properties of $^{15}\mathrm{
Both isoscalar and isovector spin-dipole excitations of ${}^{4}$He are studied using realistic nuclear forces in the complex scaling method. The ground state of ${}^{4}$He and discretized continuum states with ${J}^{\ensuremath{\pi}}={0}^{\ensuremath{-}},\phantom{\rule{0.16em}{0ex}}{1}^{\ensuremath{-}},\phantom{\rule{0.16em}{0ex}}{2}^{\ensuremath{-}}$ for $A=4$ nuclei are described in explicitly correlated Gaussians reinforced with global vectors for angular motion. Two- and three-body decay cha
The potential parameter V 0 used in the phenomenological mean-field calculation for 15 C is wrong. The value V 0 = 40.09 MeV used for the neutron potential strength of 15 C, was incorrect and should be ignored. In fact, no V 0 value correctly reproducing the one-neutron separation energy (1.22 MeV) for the configuration of 15 C listed in Table II could be found. With the spin-orbit strength of Eq. ( MeV. Because of this error, the values (1.79 and 0.944) for 15 C given in Table IV must be ignore
Background: Nuclear radius is one of the most important and basic properties of atomic nuclei and its evolution is closely related to the saturation of the nuclear density in the internal region but the systematics of the nuclear radii for the neutron-rich unstable nuclei is not well known.Purpose: Motivated by the recent interaction cross section measurement which indicates the $^{48}\mathrm{Ca}$ core swelling in the neutron-rich Ca isotopes, we explore the mechanism of the enhancement of the n
We present a systematic analysis of the total reaction cross sections of light unstable nuclei, Ne and Mg isotopes on a ^12C target with the Glauber model. The density distributions for protons and neutrons are generated by the Skyrme-Hartree-Fock method in the three-dimensional coordinate space. The calculated total reaction cross sections consistently agree with the very recent total and interaction cross section data of neutron-rich Ne and Mg isotopes, reflecting the large nuclear deformation
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