A5031223054- Nuclear physics research studies
- Quantum Chromodynamics and Particle Interactions
- Atomic and Molecular Physics
- Astronomical and nuclear sciences
- Advanced NMR Techniques and Applications
- Advanced Chemical Physics Studies
- Nuclear Physics and Applications
- Scientific Research and Discoveries
- Particle physics theoretical and experimental studies
- Neutrino Physics Research
- Particle Detector Development and Performance
- Astro and Planetary Science
- Atomic and Subatomic Physics Research
- High-pressure geophysics and materials
- Quantum, superfluid, helium dynamics
- Rare-earth and actinide compounds
- Cold Atom Physics and Bose-Einstein Condensates
- Nuclear reactor physics and engineering
- Parallel Computing and Optimization Techniques
- High-Energy Particle Collisions Research
- Particle accelerators and beam dynamics
- Radiation Detection and Scintillator Technologies
- X-ray Spectroscopy and Fluorescence Analysis
- Dark Matter and Cosmic Phenomena
- Particle Accelerators and Free-Electron Lasers
University of Tsukuba
2022-2025
The University of Tokyo
2015-2024
RIKEN
2001-2024
RIKEN Nishina Center
2009-2023
Advanced Science Research Center
2011-2023
Japan Atomic Energy Agency
2011-2023
Kansai University
2022
Pandora (United States)
2022
KU Leuven
2017
University of Göttingen
2017
In the original version of this manuscript, an error was introduced on pp352. '2.7nb:1.6nb' has been corrected to '2.4nb:1.3nb' in current online and printed version. doi:10.1093/ptep/ptz106.
The rapid shape change in Zr isotopes near neutron number N=60 is identified to be caused by type II shell evolution associated with massive proton excitations its 0g_{9/2} orbit, and shown a quantum phase transition. Monte Carlo shell-model calculations are carried out for of N=50-70 many configurations spanned eight orbits orbits. Energy levels B(E2) values obtained within single framework good agreement experiment, depicting various shapes going from N=50 70. novel coexistence prolate...
In this Letter, we present mass-ratio measurements on highly charged <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:msup><a:mrow><a:mi>Yb</a:mi></a:mrow><a:mrow><a:mn>42</a:mn><a:mo>+</a:mo></a:mrow></a:msup></a:mrow></a:math> ions with a precision of <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:mn>4</c:mn><c:mo>×</c:mo><c:msup><c:mn>10</c:mn><c:mrow><c:mo>−</c:mo><c:mn>12</c:mn></c:mrow></c:msup></c:math> and isotope-shift...
We show how shape transitions in the neutron-rich exotic Si and S isotopes occur terms of shell-model calculations with a newly constructed Hamiltonian based on V_MU interaction. first compare calculated spectroscopic-strength distributions for proton 0d_5/2,3/2 1s_1/2 orbitals results extracted from 48Ca(e,e'p) experiment to importance tensor-force component Hamiltonian. Detailed excitation energies, B(E2) two-neutron separation energies excellent agreement experimental data. The potential...
The shapes of neutron-rich exotic Ni isotopes are studied. Large-scale shell model calculations performed by advanced Monte Carlo Shell Model (MCSM) for the $pf$-$g_{9/2}$-$d_{5/2}$ space. Experimental energy levels reproduced well a single fixed Hamiltonian. Intrinsic analyzed MCSM eigenstates. Intriguing interplays among spherical, oblate, prolate and gamma-unstable seen including shape fluctuations, $E$(5)-like situation, magicity doubly-magic $^{56,68,78}$Ni, coexistence spherical...
We present a newly enhanced version of the Monte Carlo shell-model (MCSM) method by incorporating conjugate gradient and energy-variance extrapolation. This new enables us to perform large-scale calculations that direct diagonalization cannot reach. new-generation framework MCSM provides with powerful tool very advanced on current massively parallel computers such as K computer. discuss validity this in ab initio light nuclei, propose describe intrinsic wave function terms picture. also...
High-resolution inelastic electron scattering on ${}^{96}$Zr establishes shape coexistence---where two nearby states possess distinct shapes---for this nucleus. Monte Carlo shell-model calculations indicate that the change in Zr isotopes is a quantum phase transition.
We present the first application of newly developed EKK theory effective nucleon-nucleon interaction to shell-model studies exotic nuclei, including those where conventional approaches with fitted interactions encounter difficulties. This enables us derive suitable for several major shells ($sd$+$pf$ in this work). By using such an obtained from Entem-Machleidt QCD-based $\chi\mathrm{N}^3\mathrm{LO}$ and Fujita-Miyazawa three-body force, energies, E2 properties spectroscopic factors...
We present the nuclear matrix element for neutrinoless double-beta decay of ^{48}Ca based on large-scale shell-model calculations including two harmonic oscillator shells (sd and pf shells). The excitation spectra ^{48}Ti, two-neutrino are reproduced in good agreement to experimental data. find that is enhanced by about 30% compared pf-shell calculations. This reduces lifetime almost a factor 2. matrix-element increase mostly due pairing correlations associated with cross-shell sd-pf...
A novel shape evolution in the Sn isotopes by state-of-the-art application of Monte Carlo Shell Model calculations is presented a unified way for 100-138Sn isotopes. large model space consisting eight single-particle orbits protons and neutrons taken with fixed Hamiltonian effective charges, where 1g9/2 orbital are fully activated. While significant increase B(E2; 0+1 -> 2+1) value, seen around 110Sn as function neutron number (N), has remained major puzzle over decades, it explained...
One of the strongest challenges to shell-model concept nuclei are islands inversion, where empirical evidence shows ground states being dominated by intruder configurations, i.e., that would be excitations in normal picture. Whereas phenomenological calculations have previously supported this concept, work Miyagi $e\phantom{\rule{0}{0ex}}t$ $a\phantom{\rule{0}{0ex}}l$. demonstrates how one can arrive at these non-intuitive results from an $a\phantom{\rule{0}{0ex}}b$...
Abstract A long-standing crucial question with atomic nuclei is whether or not α clustering occurs there. An particle (helium-4 nucleus) comprises two protons and neutrons, may be the building block of some nuclei. This a very beautiful fascinating idea, indeed plausible because particularly stable large binding energy. However, direct experimental evidence has never been provided. Here, we show how (-like) objects emerge in nuclei, by means state-of-the-art quantum many-body simulations...
Subjecting a physical system to extreme conditions is one of the means often used obtain better understanding and deeper insight into its organization structure. In case atomic nucleus, such approach investigate isotopes that have very different neutron-to-proton (N/Z) ratios than in stable nuclei. Light, neutron-rich exhibit most asymmetric N/Z those lying beyond limits binding, which undergo spontaneous neutron emission exist only as short-lived resonances (about 10-21 s), provide...
A novel way of determining the Hamiltonian interacting boson model (IBM) is proposed. Based on fact that potential energy surface mean-field model, e.g., Skyrme can be simulated by IBM, parameters IBM are obtained. By this method, multifermion dynamics deformation mapped, in a good approximation, onto system. The validity process examined for Sm and Ba isotopes, an application presented to unexplored territory nuclear chart, namely, right lower corner 208Pb.
The interacting boson model (IBM) Hamiltonian is determined microscopically for general cases of low-lying quadrupole collectivity. Under the assumption that multinucleon-induced surface deformations, which reflect nuclear forces and Pauli principle, can be simulated by bosons, interaction strengths IBM are derived mapping potential energy mean-field with Skyrme force onto corresponding one IBM. These turn out to change gradually as functions valence nucleon numbers. eigenvalues wave...
We report no-core solutions for properties of light nuclei with three different approaches in order to assess the accuracy and convergence rates each method. Full configuration interaction (FCI), Monte Carlo shell model (MCSM) no core full (NCFC) are solved separately ground state energy other seven using realistic JISP16 nucleon-nucleon interaction. The results consistent among approaches. methods differ significantly how required computational resources scale increasing particle number a...
We study the double Gamow-Teller (DGT) strength distribution of $^{48}\mathrm{Ca}$ with state-of-the-art large-scale nuclear shell model calculations. Our analysis shows that centroid energy DGT giant resonance depends mostly on isovector pairing interaction, while width is more sensitive to isoscalar pairing. Pairing correlations are also key in neutrinoless $\ensuremath{\beta}\ensuremath{\beta}$ ($0\ensuremath{\nu}\ensuremath{\beta}\ensuremath{\beta}$) decay. find a simple relation between...
The internal-conversion and internal-pair-production decays of the first excited 0${}^{+}$ state in $^{68}\mathrm{Ni}$ are studied following $\ensuremath{\beta}$ decay $^{68}\mathrm{Co}$. A novel experimental technique, which ions $^{68}\mathrm{Co}$ were implanted into a planar germanium double-sided strip detector required digital pulse processing, is developed. values for energy electric monopole transition strength from to ground determined be 1605(3) keV...
We propose a novel formulation of the interacting boson model (IBM) for rotational nuclei with axially symmetric, strong deformation. The intrinsic structure represented by potential-energy surface (PES) given multinucleon system has certain similarity to that corresponding multiboson system. Based on this feature, one can derive an appropriate Hamiltonian, as already reported. This prescription, however, major difficulty in spectra strongly deformed nuclei: bosonic moment inertia is...
γ softness in atomic nuclei is investigated the framework of energy density functionals. By mapping constrained microscopic surfaces for a set representative nonaxial medium-heavy and heavy to Hamiltonian proton-neutron interacting boson model (IBM-2) containing up three-body interactions, low-lying collective spectra transition rates are calculated. Observables analyzed that distinguish between two limiting geometrical pictures nuclei: rigid-triaxial rotor γ-unstable rotor. It shown neither...
The low-lying structure of the neutron-rich nucleus $^{50}\mathrm{Ar}$ has been investigated at Radioactive Isotope Beam Factory using in-beam $\ensuremath{\gamma}$-ray spectroscopy with $^{9}\mathrm{Be}(^{54}\mathrm{Ca},^{50}\mathrm{Ar}+\ensuremath{\gamma})X$, $^{9}\mathrm{Be}(^{55}\mathrm{Sc},^{50}\mathrm{Ar}+\ensuremath{\gamma})X$, and $^{9}\mathrm{Be}(^{56}\mathrm{Ti},^{50}\mathrm{Ar}+\ensuremath{\gamma})X$ multinucleon removal reactions $\ensuremath{\sim}220\text{...