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Nuclear Theory·nucl-th

Tuesday·September 21, 2021

14 papers—7 primary·7 cross-listed

All14Primary7Cross-lists7
  1. 01

    [Submitted on 17 Sept 2021]

    Fusion Driven Transmutation of Transuranics in a Molten Salt

    Joshua Tanner🇺🇸 · Ales Necas🇺🇸 · Sydney Gales🇫🇷 · Gerard Mourou🇫🇷 · Toshiki Tajima🇺🇸

    A first set of computational studies of transmutation of spent nuclear fuel using compact tunable 14 MeV D-T fusion driven neutron sources is presenter. Where we study the controllability, time evolution, as well as effects of spatial distribution of the neutronics in the transmutation in the subcritical operations regime of a transmutator, in which our neutron sources are small, distributed, and can be monitored. Source neutrons are generated via beam-target fusion whereas a deuteron beam is created by laser irradiation of nanometric foils, through the Coherent Acceleration of Ions by Laser (CAIL) process, onto a tritium soaked target. This can be accomplished using relatively cheap fiber lasers terminating onto small scale targets which makes possible the use of multiple tunable and distributable neutron sources. This source is then combined with a molten salt core whose liquid state allows: homogeneity by mixing, safety, in-situ processing, and monitoring. Such a source and molten salt combination allows for the introduction of rapid feedback or feedforward control of the system's operation that have not previously been considered. This encourages an investigation with the aid of AI into new spatial and operation control strategies as done here.

    Comments:
    31 pages, 12 figures
    Subjects:
    Nuclear Theory (nucl-th); Accelerator Physics (physics.acc-ph)
    arXiv:
    2109.08741 [pdf]
    0 citations
  2. 02

    [Submitted on 17 Sept 2021]

    General Tensor Structure for Inclusive and Semi-inclusive Electron Scattering from Polarized Spin 1/2 Targets

    T. W. Donnelly🇺🇸 · Sabine Jeschonnek🇺🇸 · J. W. Van Orden🇺🇸

    The general structure of semi-inclusive polarized electron scattering from polarized spin-1/2 targets is developed for use at all energy scales, from modest-energy nuclear physics applications to use in very high energy particle physics. The leptonic and hadronic tensors that enter in the formalism are constructed in a general covariant way in terms of kinematic factors that are frame dependent but model independent and invariant response functions which contain all of the model-dependent dynamics. In the process of developing the general problem the relationships to the conventional responses expressed in terms of the helicity components of the exchanged virtual photon are presented. For semi-inclusive electron scattering with polarized electrons and polarized spin-1/2 targets one finds that 18 invariant response functions are required, each depending on four Lorentz scalar invariants. Additionally it is shown how the semi-inclusive cross sections are related via integrations over the momentum of the selected coincidence particle and sums over open channels.

    Comments:
    Minor typos corrected in this version. This is a longer, more detailed version than the published paper. The published paper also contains a historical review
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2109.08767 [pdf]
    Annals of Physics, Volume 448, January 20…·5 citations
  3. 03

    [Submitted on 20 Sept 2021]

    Dipole excitation of Li and Be studied with an extended quantum molecular dynamics model

    Bo-Song Huang · Yu-Gang Ma

    The (He) - clustering structure is a common phenomenon in light nuclei due to the decreasing contribution of mean field in few-body system. In this work we presented calculations of giant dipole resonance (GDR) excitations for two non -conjugate light nuclei, namely Li and Be, within a framework of an extended quantum molecular dynamics model. For Li, we investigated the GDR spectra from the two-body clustering structure with + deuteron as well as the three-body structure with + + , and found that the major -clustering contribution on the GDR peak is located at around 31 MeV, while the resonance contributions between clusters, namely and deuteron or ( + ), are located on the lower energy side, which can be regarded as pygmy dipole resonance (PDR). For Be, a mixture configuration contribution for the Chain-like structure and Borromean-like structure of the + n + configuration can somehow explain its GDR results.

    Comments:
    8 pages, 5 figures
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2109.09430 [pdf]
    PRC(2021)·26 citations
  4. 04

    [Submitted on 20 Sept 2021]

    Systematic Nuclear Uncertainties in the Hypertriton System

    Thiri Yadanar Htun · Daniel Gazda · Christian Forssén · Yupeng Yan

    The hypertriton bound state is relevant for inference of knowledge about the hyperon-nucleon (YN) interaction. In this work we compute the binding energy of the hypertriton using the ab initio hypernuclear no-core shell model (NCSM) with realistic interactions derived from chiral effective field theory. In particular, we employ a large family of nucleon-nucleon interactions with the aim to quantify the theoretical precision of predicted hypernuclear observables arising from nuclear-physics uncertainties. The three-body calculations are performed in a relative Jacobi-coordinate harmonic oscillator basis and we implement infrared correction formulas to extrapolate the NCSM results to infinite model space. We find that the spread of the predicted hypertriton binding energy, attributed to the nuclear-interaction model uncertainty, is about 100 keV. In conclusion, the sensitivity of the hypertriton binding energy to nuclear-physics uncertainties is of the same order of magnitude as experimental uncertainties such that this bound-state observable can be used in the calibration procedure to constrain the YN interactions.

    Comments:
    7 pages, 3 figures, proceedings of the APFB2020 conference (1-5 March 2021, Kanazawa, Japan)
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2109.09479 [pdf]
    Few Body Syst.(2021)·9 citations
  5. 05

    [Submitted on 20 Sept 2021]

    Chiral Effective Field Theory after Thirty Years: Nuclear Lattice Simulations

    Dean Lee🇺🇸

    The introduction of chiral effective field theory by Steven Weinberg three decades ago has had a profound and lasting impact on nuclear physics. This brief review explores the impact of Weinberg's work on the field of nuclear lattice simulations. Rather than a summary of technical details, an effort is made to present the conceptual advances that made much of the recent progress possible.

    Comments:
    12 pages, 2 figures, invited contribution to the special issue in Few-Body Systems "Celebrating 30 years of Steven Weinberg's papers on Nuclear Forces from Chiral Lagrangians"
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Lattice (hep-lat); Nuclear Experiment (nucl-ex)
    arXiv:
    2109.09582 [pdf]
    Few Body Syst.(2021)·3 citations
  6. 06

    [Submitted on 20 Sept 2021]

    Novel Bayesian neural network based approach for nuclear charge radii

    Xiao-Xu Dong · Rong An · Jun-Xu Lu · Li-Sheng Geng

    Charge radius is one of the most fundamental properties of a nucleus. However, a precise description of the evolution of charge radii along an isotopic chain is highly nontrivial, as reinforced by recent experimental measurements. In this paper, we propose a novel approach which combines a three-parameter formula and a Bayesian neural network. We find that the novel approach can describe the charge radii of all and nuclei with a root-mean-square deviation about 0.015 fm. In particular, the charge radii of the calcium isotopic chain are reproduced very well, including the parabolic behavior and strong odd-even staggerings. We further test the approach for the potassium isotopes and show that it can describe well the experimental data within uncertainties.

    Comments:
    13 pages, 4 figures, to appear in Physical Review C
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2109.09626 [pdf]
    PRC(2022)·76 citations
  7. 07

    [Submitted on 20 Sept 2021]

    Green-Kubo formula for Boltzmann and Fermi-Dirac statistics

    X. G. Deng · Y. G. Ma · Y. X. Zhang

    Shear viscosity of nuclear matter is extracted via the Green-Kubo formula and the Gaussian thermostated SLLOD algorithm (the shear rate method) in a periodic box by using an improved quantum molecular dynamic (ImQMD) model without mean field, also it is calculated by a Boltzmann-type equation. Here a new form of the Green-Kubo formula is put forward in the present work. For classical limit at nuclear matter densities of and , shear viscosity by the traditional and new form of the Green-Kubo formula as well as the SLLOD algorithm are coincident with each other. However, for non-classical limit, shear viscosity by the traditional form of the Green-Kubo formula is higher than those obtained by the new form of the Green-Kubo formula as well as the SLLOD algorithm especially in low temperature region. In addition, shear viscosity from the Boltzmann-type equation is found to be less than that by the Green-Kubo method or the SLLOD algorithm for both classical and non-classical limits.

    Comments:
    8 pags, 5 figures
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2109.09631 [pdf]
    EPJA(2021)·4 citations

Affiliations

first authorsco-authorsvia INSPIRE