Nuclear Theory·nucl-th

Friday·August 15, 2025

9 papers—2 primary·7 cross-listed

01
[Submitted on 14 Aug 2025]
Triaxial relativistic Hartree-Bogoliubov theory in continuum for exotic nuclei
Kaiyuan Zhang · Shuangquan Zhang · Jie Meng
A triaxial relativistic Hartree-Bogoliubov theory in continuum (TRHBc) has been developed to incorporate triaxial deformation, pairing correlations, and continuum effects in a fully microscopic and self-consistent way, aiming for a reliable description of triaxial exotic nuclei with extreme neutron-to-proton ratios. The TRHBc formalism is presented in detail, and its numerical implementation is benchmarked against the results from the axially deformed relativistic Hartree-Bogoliubov theory in continuum and the TRHB theory in harmonic oscillator expansion. The TRHBc theory is applied to investigate the aluminum isotopes systematically, and the available data are well reproduced for the binding energies, one- and two-neutron separation energies, and charge radii. The nuclei near the one-neutron drip line, $^{40}$ Al and $^{42}$ Al, are found to be triaxially deformed with one-neutron separation energies below 1 MeV. Possible neutron halos in the triaxial nuclei $^{40}$ Al and $^{42}$ Al are explored by examining the single-particle levels around the Fermi surface, including their composition and contribution to the total neutron density. The existence of neutron halos in $^{40}$ Al and $^{42}$ Al is also supported by the halo scale, which is comparable to other halo nuclei well-established previously. More importantly, the mechanism for the halo formation in $^{40}$ Al is revealed to be the triaxial deformation, which results in the decoupling of the halo orbitals from those of the core.
Comments:
revised according to referee's suggestion, accepted for publication in Phys. Rev. C, 55 pages, 14 figures, 4 tables
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2508.10420 [pdf]
PRC(2025)·11 citations
02
[Submitted on 14 Aug 2025]
Ab initio computations of the fourth-order charge density moments of $^{48}$ Ca and $^{208}$ Pb
T. Miyagi · M. Heinz · A. Schwenk
Neutron skins of neutron-rich nuclei connect nuclei with the matter in neutron stars. High-precision measurements of nuclear charge densities to extract higher-order moments are proposed to be sensitive to neutron radii and skin thicknesses. We investigate the charge density of $^{48}$ Ca and $^{208}$ Pb, leading candidates for such studies, with ab initio nuclear structure calculations. We find strong correlations between the fourth-order charge density moment $R_{ch}^{4}$ and the charge and neutron radii, allowing us to predict $R_{ch}^{4}$ for $^{48}$ Ca and $^{208}$ Pb. We find a substantially weaker correlation between the fourth-order charge density moment and the neutron skin, limiting the ability of high-precision electron scattering to determine the neutron skin in a model-independent manner.
Comments:
7 pages, 3 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2508.10767 [pdf]
PLB(2026)·10 citations
03
[Submitted on 13 Aug 2025] (cross-list from hep-ph)
Baryon-baryon, meson-meson, and meson-baryon interactions in nonrelativistic QCD
Benoît Assi🇺🇸 · Anthony Grebe🇺🇸 · Michael Wagman🇺🇸
Van der Waals potentials describing interactions between color-singlet mesons and/or baryons vanish at leading order in potential nonrelativistic quantum chromodynamics (pNRQCD). This result and constraints from Gauss's law are used to prove that weakly-coupled pNRQCD van der Waals potentials in generic non-Abelian gauge theories with only heavy quarks are too weak to form bound states whose color state is a product of color-singlets. Quantum Monte Carlo calculations of four, five, and six quarks with equal masses provide numerical evidence that exotic color configurations are higher energy than products of color-singlet hadrons, suggesting that equal-mass fully-heavy tetraquark, pentaquark, and hexaquark bound states do not exist at next-to-leading order in pNRQCD and at all orders in QCD-like theories in which all quark masses are asymptotically large. Mechanisms for generating hadron-hadron bound states are identified, which necessarily involve large quark-mass hierarchies, relativistic effects arising from the presence of sufficiently light quarks, or nonperturbative effects outside the scope of weakly-coupled pNRQCD.
Comments:
23 pages, 6 figures. Journal version. Discussion expanded and minor corrections
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2508.10090 [pdf]
PRD(2026)·3 citations
04
[Submitted on 13 Aug 2025] (cross-list from hep-ph)
Spectral function approach in NuWro: modeling of multinucleon final states in quasielastic scattering
Artur M. Ankowski🇵🇱 · Rwik Dharmapal Banerjee🇵🇱 · Jan T. Sobczyk🇵🇱 · José L. Bonilla🇵🇱 · Krzysztof M. Graczyk🇵🇱 · Beata E. Kowal🇵🇱 · Hemant Prasad🇵🇱
Neutrino-oscillation experiments performed in the few-GeV energy region create an urgent demand for a significant improvement in the accuracy of modeling of neutrino interactions with atomic nuclei. Here, we report an updated implementation of the spectral function approach in the \nuwro{} Monte Carlo generator, which consistently treats multinucleon final-states in quasielastic scattering at the inclusive and exclusive level. After validating its accuracy against inclusive electron-scattering data, we compare its predictions to various neutrino cross sections from MicroBooNE. We find that with the multinucleon contribution, these data are reproduced with $χ^{2}$ per degree of freedom of 1.3--1.8, compared to 2.7--7.2 without it.
Comments:
10 pages, 11 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2508.10101 [pdf]
4 citations
05
[Submitted on 13 Aug 2025] (cross-list from hep-ph)
Effective Field Theory Factorization for Diffraction
Kyle Lee🇺🇸 · Stella T. Schindler🇺🇸 · Iain W. Stewart🇺🇸
We derive a factorization formula for coherent and incoherent $e p$ diffraction using the soft collinear effective theory, utilizing multiple power expansion parameters to handle different kinematic regions. This goes beyond the known hard-collinear diffractive factorization to address the small- $x$ Regge dynamics and Pomeron exchange from first principles. The effective field theory analysis also uncovers and factorizes an important irreducible incoherent background generated by color-nonsinglet exchange, dubbed "quasi-diffraction", for which we calculate the associated Sudakov suppression. For unpolarized scattering we show that there are four diffractive structure functions at leading power, and point out the importance of studying $F_{3, 4}^{D}$ through asymmetries, in addition to $F_{2, L}^{D}$ . For the quasi-diffractive background, we make model independent predictions for ratios of the corresponding structure functions in a perturbative kinematic region. Our analysis also makes predictions for six leading-power spin-dependent structure functions. Finally, we provide connections to diffractive parton distributions, and assess the Ingelman-Schlein model. Our work lays a path for further QCD-based studies of diffraction.
Comments:
100 pages, 19 figures, 4 tables
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2508.10231 [pdf]
JHEP(2025)·8 citations
06
[Submitted on 14 Aug 2025] (cross-list from hep-lat)
Probing Nucleon- $Ω_{ccc}$ Interaction via Lattice QCD at Physical Quark Masses
Liang Zhang🇨🇳 · Takumi Doi🇯🇵 · Yan Lyu🇯🇵 · Tetsuo Hatsuda🇯🇵 · Yu-Gang Ma🇨🇳
We study the S-wave interactions between the nucleon ( $N$ ) and the triply charmed Omega baryon ( $Ω_{ccc}$ ) using (2+1)-flavor lattice QCD with a physical pion mass ( $m_{π} ≃ 137.1$ MeV) on a lattice volume $≃ (8.1 fm)^{3}$ . The charm quark is implemented with a relativistic heavy-quark action at its physical mass. Employing the time-dependent HAL QCD method, the $N$ - $Ω_{ccc}$ potentials in the spin-1 ( $^{3} S_{1}$ ) and spin-2 ( $^{5} S_{2}$ ) channels are extracted. In both channels, overall attraction is found with the scattering parameters, $a_{0} = 0.56 (0.13) (_{- 0.03}^{+ 0.26})$ fm and $r_{eff} = 1.60 (0.05) (_{- 0.12}^{+ 0.04})$ fm for the $^{3} S_{1}$ channel, and $a_{0} = 0.38 (0.12) (_{- 0.00}^{+ 0.25})$ fm and $r_{eff} = 2.04 (0.10) (_{- 0.22}^{+ 0.03})$ fm for the $^{5} S_{2}$ channel, indicating the absence of a dibaryon bound state. The extracted potentials are further decomposed into spin-independent and spin-dependent components. The spin-independent potential is a dominant component and features a short-range attractive core and a long-range attractive tail, while the spin-dependent potential shows short-range attraction (repulsion) in the spin-1 (spin-2) channel. Qualitative comparisons with previous studies of the $N$ - $J / ψ$ and $N$ - $Ω_{sss}$ systems at $m_{π} ≃ 146$ MeV are provided, emphasizing the role of heavy-hadron chromo-polarizability arising from soft-gluon exchange between the nucleon and flavor-singlet hadrons. The charm quark mass dependence of the $N$ - $Ω_{ccc}$ potential is investigated as well.
Comments:
8 pages, 6 figures and 3 tables
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2508.10388 [pdf]
PLB(2025)·8 citations
07
[Submitted on 14 Aug 2025] (cross-list from hep-th)
Momentum expansions in finite-density perturbative calculations
Mika Nurmela🇫🇮 · Juuso Österman🇫🇮
Complex-valued Feynman integrals in the imaginary time formalism and zero-temperature limit suffer from particular types of infrared divergences that can not be regulated by integration dimension alone. Related problems leading to integration order dependent results are even further pronounced in the presence of additional scales such as external momenta. This plays a noticeable role in systems featuring fermionic degrees of freedom such as cold Quantum Chromodynamics, where loop integrals are complexified by chemical potential(s). Working in the limit of vanishing temperature, we utilize novel complex-valued extensions to bubble Feynman integrals and study momentum expansions of fermionic loop integrals. The expansions are then used to illustrate the mechanisms of manifested discrepancies between orders of integration, associated with the residue theorem. Finally, we address the issues by introducing a representation avoiding the observed ambiguity and briefly overview classes of integrals insensitive to problems from external momenta.
Comments:
54 pages, 2 figures (v3: minor modifications following referee comments)
Subjects:
High Energy Physics — Theory (hep-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2508.10623 [pdf]
PRD(2025)·0 citations
08
[Submitted on 14 Aug 2025] (cross-list from astro-ph.HE)
Investigating the Impact of Higher-Order Phase Transitions in Binary Neutron-Star Mergers
P. Hammond🇺🇸 · A. Clevinger🇺🇸 · M. Albino🇵🇹 · V. Dexheimer🇺🇸 · S. Bernuzzi🇩🇪 · C. Brown🇺🇸 · W. Cook🇩🇪 · B. Daszuta🇩🇪 · J. Fields🇺🇸 · E. Grundy🇺🇸 · C. Providência🇵🇹 · D. Radice🇺🇸 · A. Steiner🇺🇸
In this paper we investigate quark deconfinement in neutrons stars and their mergers, focusing on the effects of higher orders for the phase transition between hadronic and quark matter. The different descriptions we use to describe matter microscopically contain varying particle degrees of freedom, including nucleons, hyperons, Delta baryons, and light and strange quarks. We use tabulated equations of state from the CompOSE database in which the quark deconfinement phase transition is described as being first-order, and then smooth it out by introducing a percolation, replacing the single first-order phase transition with two transitions of second or third order. We then perform binary neutron-star merger simulations using these new equations of st ate, focusing on groups of binaries with the same single-star mass, radius, and tidal deformability, but different equations of state. We go on to discuss differences in their evolution, and the ramifications for interpreting future gravitational wave observations and the potential to learn about dense matter.
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); Nuclear Theory (nucl-th)
arXiv:
2508.10698 [pdf]
PRD(2026)·13 citations
09
[Submitted on 14 Aug 2025] (cross-list from astro-ph.HE)
Macroscopic approaches to rotating neutron stars
A.A. Uleiev · A.G. Magner · S.P. Maydanyuk · A. Bonasera · H. Zheng · S.N. Fedotkin · A.I. Levon · U.V. Grygoriev · T. Depastas
The macroscopic model for a neutron star (NS) as a perfect liquid drop at equilibrium is extended to rotating systems with a small frequency $ω$ within the effective-surface (ES) approach. The gradient surface terms of the NS energy density $E (ρ)$ in the Equation of State are taken into account along with the volume components at the leading order over the leptodermic parameter $a / R << 1$ , where $a$ is the ES crust thickness and $R$ is the mean NS radius. The macroscopic NS angular momentum at small frequencies $ω$ is used for calculations of the adiabatic moment of inertia (MI) within the Kerr metric approach in the outer Boyer-Lindquist and inner Hogan coordinate forms. The NS MI, $Θ = Θ ~ / (1 - G_{tφ})$ , was obtained in terms of the statistically averaged MI, $Θ ~$ , and its time and azimuthal-angle correlation, $G_{tφ}$ , as the sums of volume and surface components. The MI $Θ$ depends dramatically on the effective radius $R$ due to strong gravitation and surface effects. We found significant additional rotational constraints on the radius $R$ due to the correlation term $G_{tφ}$ and surface contributions. With these contributions, the adiabaticity condition is better fulfilled for a stronger gravitation in many well-known neutron stars.
Comments:
21 pages, 4 figures. arXiv admin note: text overlap with arXiv:2403.01445
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Theory (nucl-th)
arXiv:
2508.10717 [pdf]
Nucl.Phys.Atom.Energy(2026)·0 citations

Affiliations

first authorsco-authorsvia INSPIRE