Search results for "Nuclear shell model"
showing 10 items of 50 documents
No-core configuration-interaction model for the isospin- and angular-momentum-projected states
2016
[Background] Single-reference density functional theory is very successful in reproducing bulk nuclear properties like binding energies, radii, or quadrupole moments throughout the entire periodic table. Its extension to the multi-reference level allows for restoring symmetries and, in turn, for calculating transition rates. [Purpose] We propose a new no-core-configuration-interaction (NCCI) model treating properly isospin and rotational symmetries. The model is applicable to any nucleus irrespective of its mass and neutron- and proton-number parity. It properly includes polarization effects caused by an interplay between the long- and short-range forces acting in the atomic nucleus. [Metho…
Geant4-aided Quantum State Selective Decay Spectroscopy of 213 Ra
2017
Utilizing the excellent mass resolving power of SHIPTRAP and the charged-particle-g multicoincidence setup TASISpec, the decay path of the 213Ra ground state can be exclusively studied. Based on virtual experiments with Geant4 it is possible to refine the a-branching ratios of the 213Ra ground state as well as g-ray branching ratios in the 209Rn daughter. The present study provides a proof of concept where clean quantum-state selective particle-g decay spectroscopy is used in conjunction with detailed Geant4 Monte-Carlo simulations to gain insight into nuclear structure properties.
Neutral-Current Neutrino-Nucleus Scattering off Xe Isotopes
2018
Large liquid xenon detectors aiming for dark matter direct detection will soon become viable tools also for investigating neutrino physics. Information on the effects of nuclear structure in neutrino-nucleus scattering can be important in distinguishing neutrino backgrounds in such detectors. We perform calculations for differential and total cross sections of neutral-current neutrino scattering off the most abundant xenon isotopes. The nuclear structure calculations are made in the nuclear shell model for elastic scattering, and also in the quasiparticle random-phase approximation (QRPA) and microscopic quasiparticle phonon model (MQPM) for both elastic and inelastic scattering. Using suit…
Mesonic enhancement of the weak axial charge and its effect on the half-lives and spectral shapes of first-forbidden J+↔J− decays
2018
The effects of the enhancement of the axial-charge matrix element γ5 were studied in medium heavy and heavy nuclei for first-forbidden J+↔J− decay transitions using the nuclear shell model. Noticeable dependence on the enhancement ϵMEC of the axial-charge matrix element, as well as on the value of the axial-vector coupling constant gA was found in the spectral shapes of $^{93}$Y, $^{95}$Sr, and $^{97}$Y. The importance of the spectrum of $^{138}$Cs in the determination of gA is discussed. Half-life analyses in the A≈95 and A≈135 regions were done, and consistent results gA≈0.90, 0.75, and 0.65, corresponding to the three enhancement scenarios ϵMEC=1.4, 1.7, and 2.0, were obtained. Connectio…
Dark-matter detection by elastic and inelastic LSP scattering on 129Xe and 131Xe
2008
Abstract We calculate the nuclear matrix elements involved in the elastic and inelastic scattering of the lightest supersymmetric particle (LSP) on the 129Xe and 131Xe dark-matter detector nuclei. This is the first time when both channels are addressed within the same unified microscopic nuclear framework, namely we perform large-scale shell-model calculations with a realistic two-body interaction to produce the participant nuclear wave functions. These wave functions successfully reproduce the spectroscopic data on the relevant magnetic moments and M1 decays. The tested wave functions are used to produce annual average detection rates for both the elastic and inelastic channels. It is foun…
Gamow-Teller response in the configuration space of a density-functional-theory–rooted no-core configuration-interaction model
2018
Background: The atomic nucleus is a unique laboratory in which to study fundamental aspects of the electroweak interaction. This includes a question concerning in medium renormalization of the axial-vector current, which still lacks satisfactory explanation. Study of spin-isospin or Gamow-Teller (GT) response may provide valuable information on both the quenching of the axial-vector coupling constant as well as on nuclear structure and nuclear astrophysics.Purpose: We have performed a seminal calculation of the GT response by using the no-core configuration-interaction approach rooted in multireference density functional theory (DFT-NCCI). The model treats properly isospin and rotational sy…
Nuclear shell model applied to metallic clusters
1993
We apply the nuclear shell model to jellium clusters of up to twenty-one Na atoms. Binding energies, ionization potentials, and photoabsorption cross sections are calculated and compared with mean-field results.
First-forbidden transitions in the reactor anomaly
2018
We study the dominant forbidden transitions in the antineutrino spectra of the fission actinides from 4 MeV onward using the nuclear shell model. Through explicit calculation of the shape factor, taking into account Coulomb corrections, we show the expected changes on cumulative electron and antineutrino spectra. Compared to the usual allowed approximation this results in a minor decrease of electron spectra from 4 MeV and onward, whereas an increase of several percent is observed in antineutrino spectra. We show that, despite their limited number, forbidden transitions dominate the spectral flux for most of the experimentally accessible range. Based on the shell model calculations we attem…
Evidence for a spin-aligned neutron-proton paired phase from the level structure of (92)Pd
2011
4 páginas, 4 figuras.-- El Pdf es la versión pre-print.-- et al.
Three beta-decaying states in 128In and 130In resolved for the first time using Penning-trap techniques
2020
Isomeric states in 128In and 130In have been studied with the JYFLTRAP Penning trap at the IGISOL facility. By employing state-of-the-art ion manipulation techniques, three different beta-decaying states in 128In and 130In have been separated and their masses measured. JYFLTRAP was also used to select the ions of interest for identification at a post-trap decay spectroscopy station. A new beta-decaying high-spin isomer feeding the isomer in 128Sn has been discovered in 128In at 1797.6(20) keV. Shell-model calculations employing a CD-Bonn potential re-normalized with the perturbative G-matrix approach suggest this new isomer to be a 16⁺ spin-trap isomer. In 130In, the lowest-lying (10⁻) isom…