Nuclear Theory·nucl-th

Monday·August 26, 2024

11 papers—6 primary·5 cross-listed

01
[Submitted on 23 Aug 2024]
Refining the isovector component of the Woods-Saxon potential
L. Xayavong🇰🇷 · Y. Lim🇰🇷 · N. A. Smirnova🇫🇷 · G. Nam🇰🇷
We investigate the isovector component in the phenomenological mean field model of nuclei. Lane's isospin dependence, initially proposed for the nuclear optical potential, is reexamined within the context of bound states using the Woods-Saxon potential. We demonstrate that the original parametrization can be reexpressed in terms of parameters associated with the compound nucleus, enhancing its suitability for bound states. Comparisons with the conventional symmetry term are performed to assess how well each approach fits experimental data on single-particle/hole energies and reproduces charge-radius systematics. Our results indicate that Lane's formula provides better accuracy compared with the traditional approach to the nuclear potential. Additionally, we find that the isovector component of the nuclear potential favors a surface-peaked form factor, especially one described by the first derivative of the Fermi like function divided by the radial coordinate. This consideration is crucial for open-shell nuclei where Woods-Saxon eigenfunctions serve as a realistic basis for other many-body methods. Our findings also enable discrimination among various shell-model calculations of the isospin-symmetry breaking correction to superallowed $0^{+} \to 0^{+}$ nuclear $β$ decays [I.~S. Towner and J.~C. Hardy, Phys. Rev. C {\bf 77}, 025501 (2008)]. This disparity currently constitutes the main source of theoretical uncertainty in subsequent tests of the standard model.
Comments:
13 pages, 4 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2408.12794 [pdf]
0 citations
02
[Submitted on 23 Aug 2024]
Quarkyonic equation of state with a momentum dependent interaction and neutron star structure
K. Folias🇬🇷 · Ch.C. Moustakidis🇬🇷
The structure and basic properties of dense nuclear matter still remain one of the open problems of Physics. In particular, the composition of the matter that composes neutron stars is under theoretical and experimental investigation. Among the theories that have been proposed, apart from the classical one where the composition is dominated by hadrons, the existence or coexistence of free quark matter is a dominant guess. An approach towards this solution is the phenomenological view according to which the existence of quarkyonic matter plays a dominant role in the construction of the equation of state (EOS). According to it the structure of the EOS is based on the existence of the quarkyonic particle which is a hybrid state of a particle that combines properties of hadronic and quark matter with a corresponding representation in momentum space. In this paper we propose a phenomenological model for quarkyonic matter, borrowed from corresponding applications in hadronic models, where the interaction in the quarkyonic matter depends not only on the position but also on the momentum of the quarkyonic particles. This consideration, as we demonstrate, can have a remarkable consequence on the shape of the EOS and thus on the properties of neutron stars, offering a sufficiently flexible model. Comparison with recent observational data can place constraints on the parameterization of the particular model and help improve its reliability.
Comments:
9 pages, 10 figures, 1 table. Comments are welcome
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2408.13107 [pdf]
NPA(2025)·7 citations
03
[Submitted on 23 Aug 2024]
Statistical uncertainty quantification for multireference covariant density functional theory
X. Zhang🇨🇳 · C. C. Wang🇨🇳 · C. R. Ding🇨🇳 · J. M. Yao🇨🇳
We present a theoretical framework to quantify statistical uncertainties in covariant density functional theory (CDFT) for both nuclear matter and finite nuclei, based on a relativistic point-coupling energy density functional (EDF). By sampling approximately one million parameter sets, with nine parameters varied around their values in the PC-PK1 functional, we construct a probability density function for nuclear matter properties. Incorporating empirical values of nuclear matter at saturation density and those of predictions from chiral nuclear forces, and measured $B (E 2)$ values of finite nuclei, we infer posterior distributions for the model parameters within a Bayesian framework. These posterior distributions are then propagated to the low-lying states of finite nuclei using the newly developed subspace-projected (SP)-CDFT approach, in which the wave functions of target EDF parameter sets are expanded in a subspace spanned by low-lying states obtained from a set of training parameterizations. We find that the observables of low-lying states in deformed nuclei $^{150}$ Nd and $^{150}$ Sm are well reproduced once statistical uncertainties are taken into account. In contrast, those of near spherical nuclei $^{136}$ Xe and $^{136}$ Ba remain difficult to describe within the present framework, a limitation that is expected to be alleviated by extending the model space to include quasiparticle excitations.
Comments:
12 pages with 9 figures and 3 tables
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2408.13209 [pdf]
Chinese Physics C, 2026·8 citations
04
[Submitted on 23 Aug 2024]
Spatial imaging of polarized deuterons at the Electron-Ion Collider
Heikki Mäntysaari🇫🇮 · Farid Salazar🇺🇸 · Björn Schenke🇺🇸 · Chun Shen🇺🇸 · Wenbin Zhao🇺🇸
We study diffractive vector meson production at small- $x$ in the collision of electrons and polarized deuterons $e + d^{↑}$ . We consider the polarization dependence of the nuclear wave function of the deuteron, which results in an azimuthal angular dependence of the produced vector meson when the deuteron is transversely polarized. The Fourier coefficients extracted from the azimuthal angular dependence of the vector meson differential cross-section exhibit notable differences between longitudinally and transversely polarized deuterons. The angular dependence of the extracted effective deuteron radius provides direct insight into the structure of the polarized deuteron wave function. Furthermore, we observe slightly increased gluon saturation effects when the deuteron is longitudinally polarized compared to the transversely polarized case. The small- $x$ observables studied in this work will be accessible at the future Electron-Ion Collider.
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2408.13213 [pdf]
PLB(2024)·8 citations
05
[Submitted on 23 Aug 2024]
Variational inference of effective range parameters for $^{3}$ He- $^{4}$ He scattering
Andrius Burnelis · Vojta Kejzlar · Daniel R. Phillips
We use two different methods, Monte Carlo sampling and variational inference (VI), to perform a Bayesian calibration of the effective-range parameters in $^{3}$ He- $^{4}$ He elastic scattering. The parameters are calibrated to data from a recent set of $^{3}$ He- $^{4}$ He elastic scattering differential cross section measurements. Analysis of these data for $E_{lab} \leq 4.3$ MeV yields a unimodal posterior for which both methods obtain the same structure. However, the effective-range expansion amplitude does not account for the $7/ 2^{-}$ state of $^{7}$ Be so, even after calibration, the description of data at the upper end of this energy range is poor. The data up to $E_{lab} = 2.6$ MeV can be well described, but calibration to this lower-energy subset of the data yields a bimodal posterior. After adapting VI to treat such a multi-modal posterior we find good agreement between the VI results and those obtained with parallel-tempered Monte Carlo sampling.
Comments:
13 Pages, 6 Figures
Subjects:
Nuclear Theory (nucl-th); stat.AP (stat.AP)
arXiv:
2408.13250 [pdf]
J.Phys.G(2025)·2 citations
06
[Submitted on 23 Aug 2024]
Vertex correction to nuclear matrix elements of double- $β$ decays
Jun Terasaki🇨🇿
The predicted neutrinoless double- $β$ ( $0 ν β β$ ) decay is the crucial phenomenon to prove the existence of the Majorana neutrino, which gives a foundation to leptogenesis to explain the matter prevalence of the universe. The nuclear matrix element (NME) of $0 ν β β$ decay is an important theoretical quantity to determine the effective neutrino mass and help the detector design for the next generation of the $0 ν β β$ decay search. Reliable calculation of this NME is a long-standing problem because of the diversity of the predicted values of the NME. The main reason for this difficulty is that the effective strength of the Gamow-Teller transition operator $g_{A}$ for this decay is unknown. I will show the lowest-order vertex corrections for the $0 ν β β$ and the $2 ν β β$ NME of $^{136}$ Xe in the framework of the hybrid application of the quantum field theory to the leptons and the Rayleigh-Schrödinger perturbation to the nucleus. The unperturbed nuclear states are obtained by the quasiparticle random-phase approximation. These corrections reduce the $0 ν β β$ NME by 30%. The effective $g_{A}$ referring to this reduced NME is also obtained, and it is shown for the first time that the effective $g_{A}$ for the $0 ν β β$ NME is not quite different from that for the $2 ν β β$ NME; the difference is only 10%. This indicates the possibility that the phenomenological effective $g_{A}$ to reproduce the experimental half-life of the $2 ν β β$ decay can be approximately used for the calculation of the $0 ν β β$ NME.
Comments:
6 pages, 2 figures, Submitted to proceedings of 42nd Int. Conf. on Higy Energy Physics, 18-24 July 2024, Prague; A sentence on the 2vbb NME was corrected; Equation (5) was adjusted
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2408.13254 [pdf]
PoS(2025)·0 citations
07
[Submitted on 21 Aug 2024] (cross-list from hep-ph)
$ϕ$ - $p$ bound state and completeness of quantum states
Arkadiusz Kuros🇵🇱 · Radoslaw Maj🇵🇱 · Stanislaw Mrowczynski🇵🇱
The existence of a bound state of a $ϕ$ meson and proton has been recently indicated on the basis of a combined analysis of the measured $ϕ$ - $p$ correlation function and the QCD lattice calculations of $ϕ$ - $p$ interaction in the spin 1/2 and 3/2 channels. We check whether the correlation functions and bound state formation rate satisfy the sum rule which follows from the completeness of quantum states. The sum rule is not satisfied but it is close to it, suggesting that the inferred scattering parameters, which determine the correlation functions, are not fully consistent with the potential responsible for the bound state existence.
Comments:
6 pages, 4 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2408.11941 [pdf]
2 citations
08
[Submitted on 22 Aug 2024] (cross-list from hep-ph)
Heavy-quark diffusion in 2+1D and Glasma-like plasmas: evidence of a transport peak
Liane Backfried🇦🇹 · Kirill Boguslavski🇦🇹 · Paul Hotzy🇦🇹
We examine how plasma excitations affect the heavy-quark diffusion coefficient in 2+1 dimensional and Glasma-like plasmas, akin to the pre-equilibrium matter describing relativistic heavy-ion collisions at early times. We find that the transport coefficient $2 κ$ transverse to and $κ_{z}$ along the beam direction display a qualitatively different evolution. We attribute this to the underlying excitation spectra of these systems, thus providing evidence for the existence of non-perturbative properties in the spectrum. This is accomplished by first reconstructing the diffusion coefficients using gauge-fixed correlation functions, which accurately reproduces the time evolution of $2 κ$ and $κ_{z}$ . We then modify these excitation spectra to study the impact of their non-perturbative features on the transport coefficients. In particular, we find evidence for a novel transport peak in the low-frequency spectrum that is crucial for heavy-quark diffusion. We also demonstrate that gluonic excitations are broad while scalar excitations associated with $κ_{z}$ are narrow and strongly enhanced at low momenta. Our findings indicate that the large values and dynamical properties of transport coefficients in the Glasma could originate from genuinely non-perturbative features in the spectrum.
Comments:
21 pages, 12 figures, 1 table; v2: minor revision, published version, data and plot files available under reference [49] (https://zenodo.org/records/14039178)
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2408.12646 [pdf]
PRD(2024)·9 citations
09
[Submitted on 23 Aug 2024] (cross-list from hep-lat)
Parton Distribution Function of a Deuteron-like Dibaryon System from Lattice QCD
Chen Chen🇨🇳 · Liuming Liu🇨🇳 · Peng Sun🇨🇳 · Yi-Bo Yang🇨🇳 · Yiqi Geng🇨🇳 · Fei Yao🇨🇳 · Jian-Hui Zhang🇨🇳 · Kuan Zhang🇨🇳
We report a lattice QCD calculation of the parton distribution function (PDF) of a deuteron-like dibaryon system using large-momentum effective theory. The calculation is done on three Wilson Clover ensembles with a fixed lattice spacing a=0.105 fm and two pion masses. The lattice matrix elements are computed at proton momenta up to 2.46 GeV with the signal of high momentum modes being improved by applying the momentum smearing technique. The state-of-the-art renormalization, matching and extrapolation are then applied to obtain the final result of the light-cone PDF. A comparison between the result of the dibaryon system and the sum of the proton and neutron PDFs is also given.
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2408.12819 [pdf]
PRD(2025)·21 citations
10
[Submitted on 23 Aug 2024] (cross-list from hep-ph)
Search for the $Σ (1380) 1/ 2^{-}$ state in $Λ_{c}^{+} \to γ π^{+} Λ$ decay by triangle singularity
Ke Wang🇨🇳 · Yu-Fei Wang🇨🇳 · Bo-Chao Liu🇨🇳 · Fei Huang🇨🇳
In this work, we investigate the resonance production in $Λ_{c}^{+} \to γ π^{+} Λ$ decay through the triangle singularity (TS) mechanism, within an effective Lagrangian approach. We find that the appropriate loop decay process could develop a triangle singularity in the invariant mass $M_{π Λ}$ around $1.35$ GeV, with the shape depending on the quantum numbers of $Σ^{*}$ states that couple to the final $π Λ$ system. Especially, the $Σ (1380) 1/ 2^{-}$ state newly predicted in the pentaquark model, if exists, significantly enhances the TS contribution and sharpens the TS peak due to the $S$ -wave $Σ^{*} π Σ$ vertex in the loop. Therefore, the existence of the $Σ (1380) 1/ 2^{-}$ state can be examined by measuring the TS signal in $Λ_{c}^{+} \to γ π^{+} Λ$ . Considering also possible tree-level diagrams, we additionally obtain the branching ratio $Br (Λ_{c}^{+} \to γ π^{+} Λ) ≃ 1.5 \times 1 0^{- 5}$ . We suggest the investigation of this reaction by future BESIII, LHCb, and Belle experiments.
Comments:
8 pages, 6 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2408.12965 [pdf]
PRD(2024)·9 citations
11
[Submitted on 23 Aug 2024] (cross-list from astro-ph.HE)
Generating ultra-compact neutron stars with bosonic dark matter
Sarah Louisa Pitz🇩🇪 · Jürgen Schaffner-Bielich🇩🇪
In this work we investigate the properties of neutron stars admixed with selfinteracting scalar bosonic dark matter. The dark matter interaction is described by a generalized $ϕ^{n}$ power-law potential. We perform a stability analysis of these two-fluid objects by studying the onset of the unstable radial modes. We find ultra-compact neutron star-dark matter configurations where the neutron star matter is confined to a core radius of values below $7$ km which is unreachable for pure neutron stars. The total gravitational maximum mass of these ultra-compact configurations can have values of $3.4 M_{⊙}$ . With our general ansatz of the power-law potential we show that the compactness of these solutions can be extreme, i.e. the compactness is $C = 1/3$ or even larger, making them compact enough to have a light-ring mimicking black holes. These ultra-compact objects are stable and possess a dark matter halo while having a hadronic matter core. With the addition of dark matter to neutron stars recent unusual mass-radius measurements of compact stars can be explained. We conclude that apparently contradictory measurements of neutron star masses and radii could be not only an indication of the presence of dark matter around a the hadronic matter core which is stabilized by the gravitational potential of dark matter but could also serve to disentangle the selfinteraction strength of dark matter. Our work points to a stiff equation of state for the dark matter fluid, rather than a soft one.
Comments:
12 pages, 5 figures, accepted for publication in PRD
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
arXiv:
2408.13157 [pdf]
PRD(2025)·43 citations

Affiliations

first authorsco-authorsvia INSPIRE