Nuclear Theory·nucl-th

Tuesday·September 21, 2021

14 papers—7 primary·7 cross-listed

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
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
03
[Submitted on 20 Sept 2021]
Dipole excitation of $^{6}$ Li and $^{9}$ Be studied with an extended quantum molecular dynamics model
Bo-Song Huang · Yu-Gang Ma
The $α$ ( $^{4}$ 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 $α$ -conjugate light nuclei, namely $^{6}$ Li and $^{9}$ Be, within a framework of an extended quantum molecular dynamics model. For $^{6}$ Li, we investigated the GDR spectra from the two-body clustering structure with $α$ + deuteron as well as the three-body structure with $α$ + $n$ + $p$ , and found that the major $α$ -clustering contribution on the GDR peak is located at around 31 MeV, while the resonance contributions between clusters, namely $α$ and deuteron or ( $n$ + $p$ ), are located on the lower energy side, which can be regarded as pygmy dipole resonance (PDR). For $^{9}$ Be, a mixture configuration contribution for the Chain-like structure and Borromean-like structure of the $α$ + n + $α$ 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
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
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
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 $A \geq 40$ and $Z \geq 20$ 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
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 $0.4 ρ_{0}$ and $1.0 ρ_{0}$ , 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
08
[Submitted on 16 Dec 2020] (cross-list from hep-ph)
Nucleon Structure and Strong Interactions in Dark Matter Capture in Neutron Stars
Nicole F. Bell🇦🇺 · Giorgio Busoni🇩🇪 · Theo F. Motta🇦🇺 · Sandra Robles🇦🇺 · Anthony W. Thomas🇦🇺 · Michael Virgato🇦🇺
We outline two important effects that are missing from most evaluations of the dark matter capture rate in neutron stars. As dark matter scattering with nucleons in the star involves large momentum transfer, nucleon structure must be taken into account via a momentum dependence of the hadronic form factors. In addition, due to the high density of neutron star matter, we should account for nucleon interactions rather than modeling the nucleons as an ideal Fermi gas. Properly incorporating these effects is found to suppress the dark matter capture rate by up to four orders of magnitude for the heaviest stars.
Comments:
9 pages, 5 figures. Contains erratum in the last 2 pages
Subjects:
High Energy Physics — Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
arXiv:
2012.08918 [pdf]
PRL(2021)·98 citations
09
[Submitted on 17 Sept 2021] (cross-list from hep-ph)
Pauli radius of the proton
Zhu-Fang Cui🇨🇳 · Daniele Binosi🇮🇹 · Craig D. Roberts🇨🇳 · Sebastian M. Schmidt🇩🇪
Using a procedure based on interpolation via continued fractions supplemented by statistical sampling, we analyse proton magnetic form factor data obtained via electron+proton scattering on $Q^{2} \in [0.027, 0.55]$ GeV $^{2}$ with the goal of determining the proton magnetic radius. The approach avoids assumptions about the function form used for data interpolation and ensuing extrapolation onto $Q^{2} ≃ 0$ for extraction of the form factor slope. In this way, we find $r_{M} = 0.817 (27)$ fm. Regarding the difference between proton electric and magnetic radii calculated in this way, extant data are seen to be compatible with the possibility that the slopes of the proton Dirac and Pauli form factors, $F_{1, 2} (Q^{2})$ , are not truly independent observables; to wit, the difference $F_{1}^{'} (0) - F_{2}^{'} (0) / κ_{p} = [1 + κ_{p}] / [4 m_{p}^{2}]$ , viz. the proton Foldy term.
Comments:
7 pages, 3 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2109.08768 [pdf]
Chin.Phys.Lett.(2021)·11 citations
10
[Submitted on 18 Sept 2021] (cross-list from nucl-ex)
$F t$ values of the mirror $β$ transitions and the weak magnetism induced current in allowed nuclear $β$ decay
N. Severijns🇧🇪 · L. Hayen🇧🇪 · V. De Leebeeck🇧🇪 · S. Vanlangendonck🇧🇪 · K. Bodek🇵🇱 · D. Rozpedzik🇵🇱 · I.S. Towner🇺🇸
In recent years a number of correlation measurements in nuclear $β$ decay have been performed reaching a precision of the order of 1\% and below and it is expected that even higher precision will be reached in the near future. At these levels of precision higher-order corrections due to e.g. recoil terms induced by the strong interaction and radiative corrections cannot necessarily be neglected anymore when interpreting these results in terms of new physics or extracting a value for the $V_{u d}$ quark-mixing matrix element. We provide here an update of the $F t$ values of the $T = 1/2$ mirror $β$ decays as well as an overview of current experimental and theoretical knowledge of the most important recoil term, weak magnetism, for both the $T = 1/2$ mirror $β$ transitions and a large set of $β$ decays in higher isospin multiplets. The matrix elements determining weak magnetism were calculated in the nuclear shell model and cross-checked against experimental data, showing overall good agreement. Additionally, we show that further insight can be obtained from properly deformed nuclear potentials, in particular for mirror $T = 1/2$ decays.. The results provide new insights in the size of weak magnetism, extending the available information to $β$ transitions of nuclei with masses up to $A =$ 75. This provides important guidance for the planning and interpretation of ongoing and new precise correlation measurements in nuclear $β$ decay searching for new physics or to extract the $V_{u d}$ quark-mixing matrix element in mirror $β$ decays. This more detailed knowledge of weak magnetism can also be of interest for further theoretical work related to the reactor neutrino problem.
Comments:
64 pages, 21 figures
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2109.08895 [pdf]
PRC(2023)·28 citations
11
[Submitted on 18 Sept 2021] (cross-list from hep-ph)
Spectral splits and entanglement entropy in collective neutrino oscillations
Amol V. Patwardhan🇺🇸 · Michael J. Cervia🇺🇸 · A. B. Balantekin🇺🇸
In environments such as core-collapse supernovae, neutron star mergers, or the early universe, where the neutrino fluxes can be extremely high, neutrino-neutrino interactions are appreciable and contribute substantially to their flavor evolution. Such a system of interacting neutrinos can be regarded as a quantum many-body system, and prospects for nontrivial quantum correlations, i.e., entanglement, developing in a gas of interacting neutrinos have been investigated previously. In this work, we uncover an intriguing connection between the entropy of entanglement of individual neutrinos with the rest of the ensemble, and the occurrence of spectral splits in the energy spectra of these neutrinos, which develop as a result of collective neutrino oscillations. In particular, for various types of neutrino spectra, we demonstrate that the entanglement entropy is highest for the neutrinos whose locations in the energy spectrum are closest to the spectral split(s). This trend demonstrates that the quantum entanglement is strongest among the neutrinos that are close to these splits, a behavior that seems to persist even as the size of the many-body system is increased.
Comments:
10 pages, 6 figures. v2: updated to match journal version
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
arXiv:
2109.08995 [pdf]
PRD(2021)·63 citations
12
[Submitted on 19 Sept 2021] (cross-list from hep-ph)
Mesons and Baryons: Parity Partners
L.X. Gutiérrez-Guerrero🇲🇽 · G. Paredes-Torres🇲🇽 · A. Bashir🇲🇽
We calculate masses of light and heavy mesons as well as baryons of negative parity containing $u, d, s, c$ and $b$ quarks. It is an extension of our previous work where we had studied the positive parity baryons. We adopt a quark-diquark picture of baryons where the diquarks are non-pointlike with a finite spatial extension. The mathematical foundation for this analysis is implemented through a symmetry-preserving Schwinger-Dyson equations treatment of a vector-vector contact interaction, which preserves key features of quantum chromodynamics, such as confinement, chiral symmetry breaking, axial vector Ward-Takahashi identity and low-energy Goldberger-Treiman relations. This treatment simultaneously describes mesons and provides attractive correlations for diquarks in the $3$ representation. Employing this model, we compute the spectrum and masses of all spin-1/2 and spin-3/2 baryons of negative parity, supplementing our earlier evaluation of positive parity baryons, containing 1, 2 or 3 heavy quarks. In the process, we calculate masses of a multitude of mesons and corresponding diquarks. Wherever possible, we make comparisons of our results with known experimental observations as well as theoretical predictions of several models and approaches including lattice quantum chromodynamics, finding satisfactory agreement. We also make predictions for heavier states not yet observed in the experiment.
Comments:
10 pages, 4 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2109.09058 [pdf]
PRD(2021)·37 citations
13
[Submitted on 19 Sept 2021] (cross-list from astro-ph.HE)
$r$ -process nucleosynthesis from compact binary mergers
Albino Perego🇮🇹 · Friedrich-Karl Thielemann🇨🇭 · Gabriele Cescutti🇮🇹
The merger of two neutron stars or of a neutron star and a black hole often result in the ejection of a few percents of a solar mass of matter expanding at high speed in space. Being matter coming from the violent disruption of a neutron star, these ejecta are initially very dense, hot and extremely rich in neutrons. The few available protons form heavy nuclei ("seeds") that absorb the more abundant free neutrons, increasing their size. The neutron density is so high that a substantial number of neutron captures occur before the resulting unstable nuclei can decay toward more stable configurations, converting neutrons into protons. Depending mostly on the initial neutron richness, this mechanism leads to the formation of up to half of the heavy elements that we observe in nature and it is called rapid neutron capture process (" $r$ -process"). The prediction of the precise composition of the ejecta requires a detailed knowledge of the properties of very exotic nuclei, that have never been produced in a laboratory. Despite having long been a speculative scenario, nowadays several observational evidences point to compact binary mergers as one of the major sites where heavy elements are formed in the Universe. The most striking one was the detection of a kilonova following the merger of a neutron star binary: the light emitted by this astronomical transient is indeed powered by the radioactive decay of freshly synthesized neutron-rich nuclei and testifies the actual nature of compact binary mergers as cosmic forges.
Comments:
56 pages; 14 figures, Chapter of "Handbook of Gravitational Wave Astronomy", published by Springer
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); Nuclear Theory (nucl-th)
arXiv:
2109.09162 [pdf]
20 citations
14
[Submitted on 20 Sept 2021] (cross-list from astro-ph.HE)
The nuclear matter density functional under the nucleonic hypothesis
Hoa Dinh Thi🇫🇷 · Chiranjib Mondal🇫🇷 · Francesca Gulminelli🇫🇷
A Bayesian analysis of the possible behaviors of the dense matter equation of state informed through recent LIGO-Virgo as well as NICER measurements reveals that all the present observations are compatible with a fully nucleonic hypothesis for the composition of dense matter, even in the core of the most massive pulsar PSR J0740+6620. Under the hypothesis of a nucleonic composition, we extract the most general behavior of the energy per particle of symmetric matter and density dependence of the symmetry energy, compatible with the astrophysical observations as well as our present knowledge of low energy nuclear physics from effective field theory predictions and experimental nuclear mass data. These results can be used as a null hypothesis to be confronted with future constraints on dense matter to search for possible exotic degrees of freedom.
Comments:
Submitted to Universe, invited contribution to the special Issue: Properties and Dynamics of Neutron Stars and Proto-Neutron Stars, V.Dexheimer and R.Negreiros eds., 2021
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
arXiv:
2109.09675 [pdf]
Universe(2021)·52 citations

Affiliations

first authorsco-authorsvia INSPIRE